ODB Structure

Internal features - Top - Data format

The Online Database contains information that system and user wants to share. Basically all transactions for experiment setup and monitoring go through the ODB. It also contains some specific system information related to the "Midas client" currently involved in an experiment (/system).

Each ODB field or so called KEY is accessible by the user through either an interactive way (see odbedit task) or by C-programming (see functions db_xxx in Midas Code and Libraries).

The ODB information is stored in a "tree/branch" structure where each branch refers to a specific set of data. On the first invocation of the database (first Midas application) a minimal system record will be created. Later on each application will add its own set of parameters to the database depending on its requirement. For instance, starting the ODB for the first time, the tree /Runfinfo, /Experiment, /System will be created. The application mlogger task will add its own tree /Logger/...

As mentioned earlier, ODB is the main communication platform between any Midas application. As such, the content of the ODB is application dependent. Several "dormant" trees can be awaken by the user in order to provide extra flexibility of the system. Such "dormant" tree are Alias, Script, Edit on Start , Security, Run parameters .

• ODB /System Tree
• ODB /RunInfo Tree
• ODB /Equipment Tree
• ODB /Logger Tree
• ODB /Experiment Tree
• ODB /History Tree
• ODB /Alarms Tree
• ODB /Script Tree
• ODB /Alias Tree
• ODB /Elog Tree
• ODB /Programs Tree
• ODB /Lazy Tree
• ODB /EBuilder Tree
• ODB /Custom Tree

---

ODB /System Tree

The system tree contains information specific to each "Midas client" currenltly connected to the experiment. This information is not primarly for the user but may be informative in some respect to the reader.

[host:expt:Stopped]/>ls -r -l /system
Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
System                          DIR
    Clients                     DIR
        29580                   DIR
            Name                STRING  1     32    17h  0   R    decay
            Host                STRING  1     256   17h  0   R    host1
            Hardware type       INT     1     4     17h  0   R    42
            Server Port         INT     1     4     17h  0   R    1227
            Transition Mask     DWORD   1     4     17h  0   R    329
            Deferred Transition DWORD   1     4     17h  0   R    6
            RPC                 DIR
                16000           BOOL    1     4     17h  0   R    y
                16001           BOOL    1     4     17h  0   R    y
        29638                   DIR
            Name                STRING  1     32    17h  0   R    MStatus
            Host                STRING  1     256   17h  0   R    host1
            Hardware type       INT     1     4     17h  0   R    42
            Server Port         INT     1     4     17h  0   R    1228
            Transition Mask     DWORD   1     4     17h  0   R    0
            Deferred Transition DWORD   1     4     17h  0   R    0
        29810                   DIR
            Name                STRING  1     32    17h  0   R    Nova_029810
            Host                STRING  1     256   17h  0   R    host
            Hardware type       INT     1     4     17h  0   R    42
            Server Port         INT     1     4     17h  0   R    1235
            Transition Mask     DWORD   1     4     17h  0   R    0
        29919                   DIR
            Name                STRING  1     32    17h  0   R    Epics
            Host                STRING  1     256   17h  0   R    host
            Hardware type       INT     1     4     17h  0   R    42
            Server Port         INT     1     4     17h  0   R    1237
            Transition Mask     DWORD   1     4     17h  0   R    329
            Deferred Transition DWORD   1     4     17h  0   R    0
            RPC                 DIR
                16000           BOOL    1     4     17h  0   R    y
                16001           BOOL    1     4     17h  0   R    y
        12164                   DIR
            Name                STRING  1     32    6s   0   R    ODBEdit
            Host                STRING  1     256   6s   0   R    host2
            Hardware type       INT     1     4     6s   0   R    42
            Server Port         INT     1     4     6s   0   R    4893
            Transition Mask     DWORD   1     4     6s   0   R    0
            Deferred Transition DWORD   1     4     6s   0   R    0
            Link timeout        INT     1     4     6s   0   R    10000
    Client Notify               INT     1     4     6s   0   RWD  0
    Prompt                      STRING  1     256   >99d 0   RWD  [%h:%e:%S]%p>
    Tmp                         DIR

• [Remark 1] The key Prompt sets up the prompt of the ODBEdit program.

  odbedit
  [local:midas:Stopped]/>cd /System/
  [local:midas:Stopped]/System>ls
  Clients                         
  Tmp                             
  Client Notify                   0
  Prompt                          [%h:%e:%S]%p>
  
  [local:midas:Stopped]/System>set Prompt my_prompt>
  my_prompt>set Prompt [Host:%h-Expt:%e:State:%s]Path:%p>
  [Host:local-Expt:midas-State:S]Path:/System>set Prompt [Host:%h-Expt:%e-State:%S]Path:%p>
  [Host:local-Expt:midas-State:Stopped]Path:/System>
  

---

ODB /RunInfo Tree

This branch contains system information related to the run information. Several time fields are available for run time statistics.

odb -e expt -h host
[host:expt:Running]/>ls -r -l /runinfo
Key name                      Type    #Val  Size  Last Opn Mode Value
------------------------------------------------------------------------
Runinfo                        DIR
    State                      INT     1     4     2h   0   RWD  3
    Online Mode                INT     1     4     2h   0   RWD  1
    Run number                 INT     1     4     2h   0   RWD  8521
    Transition in progress     INT     1     4     2h   0   RWD  0
    Requested transition       INT     1     4     2h   0   RWD  0
    Start time                 STRING  1     32    2h   0   RWD  Thu Mar 23 10:03:44 2000
    Start time binary          DWORD   1     4     2h   0   RWD  953834624
    Stop time                  STRING  1     32    2h   0   RWD  Thu Mar 23 10:03:33 2000
    Stop time binary           DWORD   1     4     2h   0   RWD  0

• [State] Specifies in which state the current run is. The possible states are 1: STOPPED, 2: RUNNING, 3: PAUSED.
• [Online Mode] Specifies the expected acquisition mode. This parameter allows the user to detect if the data are coming from a "real-time" hardware source or from a data save-set. Note that for analysis replay using "analyzer" this flag will be switched off.
• [Run number] Specifies the current run number. This number is automatically incremented by a successful run start procedure.
• [Transition in progress] Specifies the current internal state of the system. This parameter is used for multiple source of "run start" synchronization.
• [Requested transition] Specifies the current internal of the Deferred Transition state of the system.
• [Start Time] Specifies in an ASCII format the time at which the last run has been started.
• [Start Time binary] Specifies in a binary format at the time at which the last run has been started This field is useful for time interval computation.
• [Stop Time] Specifies in an ASCII format the time at which the last run has been stopped.
• [Stop Time binary] Specifies in a binary format the time at which the last run has been stopped. This field is useful for time interval computation.

---

ODB /Equipment Tree

Every frontend create a entry under the /Equipment tree. The name of the sub-tree is taken from the frontend source code in the equipment declaration (frontend.c). More detailed explanation of the composition of that tree will be found throughout this document.

  {
   "DspecCheck",      // equipment name
   ...
   ,
  {
   "Scaler",      // equipment name
   ...
   ,

Example:

Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
HistoCheck                      DIR
DSpecCheck                      DIR
HistoPoll                       DIR
HistoEOR                        DIR
DSpecEOR                        DIR
Scaler                          DIR
SuconMagnet                     DIR
TempBridge                      DIR
Cryostat                        DIR
Meters                          DIR
RFSource                        DIR
DSPec                           DIR

The equipment tree is then split in several sections which by default the system creates.

• Common : Contains the system information. Should not be overwritten by the user.
• Variables : Contains the equipment data if enabled (see below).
• Settings : Contains the equipment specific information that the user may want to maintain. In the case of a Slow Control System equipment, extended tree structure is created by the system.
• Statistics : Contains equipment statistics information such as event taken, event rate, data rate.

[local:S]ls -l -r /equipment/scaler
Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
Scaler                          DIR
    Common                      DIR
        Event ID                WORD    1     2     16h  0   RWD  1
        Trigger mask            WORD    1     2     16h  0   RWD  256
        Buffer                  STRING  1     32    16h  0   RWD  SYSTEM
        Type                    INT     1     4     16h  0   RWD  1
        Source                  INT     1     4     16h  0   RWD  0
        Format                  STRING  1     8     16h  0   RWD  MIDAS
        Enabled                 BOOL    1     4     16h  0   RWD  y
        Read on                 INT     1     4     16h  0   RWD  377
        Period                  INT     1     4     16h  0   RWD  1000
        Event limit             DOUBLE  1     8     16h  0   RWD  0
        Num subevents           DWORD   1     4     16h  0   RWD  0
        Log history             INT     1     4     16h  0   RWD  0
        Frontend host           STRING  1     32    16h  0   RWD  midtis03
        Frontend name           STRING  1     32    16h  0   RWD  feLTNO
        Frontend file name      STRING  1     256   16h  0   RWD  C:\online\sc_ltno.c
    Variables                   DIR
        SCLR                    DWORD   6     4     1s   0   RWD  
                                        [0]             0
                                        [1]             0
                                        [2]             0
                                        [3]             0
                                        [4]             0
                                        [5]             0
        RATE                    FLOAT   6     4     1s   0   RWD  
                                        [0]             0
                                        [1]             0
                                        [2]             0
                                        [3]             0
                                        [4]             0
                                        [5]             0
    Statistics                  DIR
        Events sent             DOUBLE  1     8     1s   0   RWDE 370
        Events per sec.         DOUBLE  1     8     1s   0   RWDE 0.789578
        kBytes per sec.         DOUBLE  1     8     1s   0   RWDE 0.0678543

---

ODB /Logger Tree

The /Logger ODB tree contains all the relevant information for the Midas logger utility (mlogger task) to run properly. This utility provides the mean of storing the physical data retrieved by the frontend to a storage media. The user has no code to write in order for the system to operate correctly. Its general behavior can be customized and multiple logging channels can be defined. The application supports so far three type of storage devices i.e.: Disk, Tape and FTP channel.

Default settings are created automatically when the logger starts the first time:

Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
Logger                          DIR
    Data dir                    STRING  1     256   4h   0   RWD  /scr0/spring2000
    Message file                STRING  1     256   22h  0   RWD  midas.log
    Write data                  BOOL    1     4     2h   0   RWD  n
    ODB Dump                    BOOL    1     4     22h  0   RWD  y
    ODB Dump File               STRING  1     256   22h  0   RWD  run%05d.odb
    Auto restart                BOOL    1     4     22h  0   RWD  y
    Tape message                BOOL    1     4     15h  0   RWD  y
    Channels                    DIR
        0                       DIR
            Settings            DIR
                Active          BOOL    1     4     1h   0   RWD  y
                Type            STRING  1     8     1h   0   RWD  Disk
                Filename        STRING  1     256   1h   0   RWD  run%05d.ybs
                Format          STRING  1     8     1h   0   RWD  YBOS
                ODB Dump        BOOL    1     4     1h   0   RWD  y
                Log messages    DWORD   1     4     1h   0   RWD  0
                Buffer          STRING  1     32    1h   0   RWD  SYSTEM
                Event ID        INT     1     4     1h   0   RWD  -1
                Trigger Mask    INT     1     4     1h   0   RWD  -1
                Event limit     DWORD   1     4     1h   0   RWD  0
                Byte limit      DOUBLE  1     8     1h   0   RWD  0
                Tape capacity   DOUBLE  1     8     1h   0   RWD  0
    Subdir format   STRING  1     32    7h   0   RWD  %Y%m%d
    Current filenameSTRING  1     256   7h   0   RWD  20020605\run00078.mid
      Statistics          DIR
                Events written  DOUBLE  1     8     1h   0   RWD  0
                Bytes written   DOUBLE  1     8     1h   0   RWD  0
                Bytes written toDOUBLE  1     8     1h   0   RWD  3.24316e+11
                Files written   INT     1     4     1h   0   RWD  334

From Midas version 1.9.5, the logger has the possibility to store information to a mySQL database. This option is an alternative to the runlog.txt update hanled by the analyzer. The two main advantages using the SQL are:

• The recording is done by the logger and therfore independent of the user analyzer.
• The definition of the parameters to be recorded in the database is entirely setup in the ODB under /logger/SQL. This SQL option is enabled by defining at build time the preprocessor flag HAVE_MYSQL. This option when enabled will create a sub tree SQL under /Logger in the ODB. This tree contains information for mySQL access with predefined mySQL database name Midas and table Runlog. Under 2 dedicated sub directories i.e: Link_BOR and Link_EOR, predefined links exists which will be used respectively at BOR and EOR for storing into the database. These elements are ODB links allowing the user to extend the list with any parameter of the ODB database. This logger mySQL option is to replace or complement the runlog.txt functionality of the ana_end_of_run() function from the analyzer.c.

[local:midas:S]/Logger>ls -lr SQL
Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
SQL                             DIR
    Create database             BOOL    1     4     27s  0   RWD  n
    Write data                  BOOL    1     4     27s  0   RWD  n
    Hostname                    STRING  1     80    27s  0   RWD  localhost
    Username                    STRING  1     80    27s  0   RWD  root
    Password                    STRING  1     80    27s  0   RWD
    Database                    STRING  1     32    27s  0   RWD  midas
    Table                       STRING  1     80    27s  0   RWD  Runlog
    Links BOR                   DIR
        Run number              LINK    1     20    58s  0   RWD  /Runinfo/Run number
        Start time              LINK    1     20    58s  0   RWD  /Runinfo/Start time
    Links EOR                   DIR
        Stop time               LINK    1     19    4m   0   RWD  /Runinfo/Stop time

• [Data dir] Specifies in which directory files produced by the logger should be written. Once the Logger in running, this Data_Dir will be pointing to the location of the midas.log , ODB dump files, history files, message files. In the case of multiple logging channels, the data path for all the channels is defaulted to the same location. In the case where specific directory has to be assigned to each individual logging channel, the field /logger/channel/<x>/Settings/Filename can contain the full path of the location of the .mid, .ybs, .asc file. By finding the OS specific SEPARATOR_DIR ("/", "\"). The field Filename will overwite the global Data_Dir setting for that particular channel.
  • [History Dir] This field is optional and doesn't appear by default in the logger. If present the location of the History system files is reassigned to the defined path instead of the default Data_Dir .
  • [Elog Dir] This field is optional and doesn't appear by default in the logger. If present the location of the Electronic Logbook files is reassigned to the defined path instead of the default Data_Dir.
  • [Message file] Specifies the file name for the log file which contains all messages from the MIDAS message system. The message log file is a simple ASCII file, which can be viewed at any time to see a history of what happened in an experiment.
    • 2.0.0 The location of the ODB dump files can now be specified in this field. If the string contains a DIRECTORY_SEPARATOR, is it considered as an absolute path.
  • [Write data] Global flag which turns data logging on and off for all channels. It can be set to zero temporarily to make a short test run without data logging. The key "Write data?" is predefined logger key for enabling data logging. This action can be overridden by setting the active key to 1.
  • [ODB Dump] Specifies if a dump of the complete ODB should be written to the file specified by ODB Dump File.
  • [ODB Dump File] At the end of each run. If the file name contains a "%", this gets replaced by the current run number similar to the printf() C function. The format specifier 05d from above would be evaluated to a five digit run number with leading zeros like run00002.odb. The ODB dump file is in ASCII format and can be used for off-line analysis to check run parameters etc. For a description of the ASCII format see db_copy().
    • 2.0.0 The location of the ODB dump files can now be specified in this field. If the string contains a DIRECTORY_SEPARATOR, is it considered as an absolute path

        [local:Default:S]/Logger>ls
        Data dir                        \online\
        Message file                    midas.log 
        Auto restart                     n
        Write data                      y
        ODB Dump                        n
        ODB Dump File                   run%05d.odb
        Tape message                    y 
        Channels
        [local:Default:S]/Logger>set OD
        ODB Dump
        ODB Dump File
        [local:Default:S]/Logger>set "ODB Dump File" "/mypath/run%06d.odb"
        [local:Default:S]/Logger>ls
        Data dir                        \online\
        Message file                    midas.log
        Auto restart                    n
        Write data                      y
        ODB Dump                        n
        ODB Dump File                   /mypath/run%06d.odb
        Tape message                    y
        Channels
      

  • [Auto restart] When this flag is one, a new run gets automatically restarted when the previous run has been stopped by the logger due to an event or byte limit.
  • [Tape message] Specifies if tape messages during mounting and writing of EOF marks are generated. This can be useful for slow tapes to inform all users in a counting house about the tape status.
  • [channels] Sub-directory which contains settings for individual channels. By default, only channel "0" is created. To define other channels, an existing channel can be copied:

      [loca]]Logger>cd channels
      [local]Channels>ls 
      0
      [local]Channels>copy 0 1
      [local]Channels>ls 
      0
      1
    

    The Settings part of the channel tree has the following meaning:
  • [active] turns a channel on (1) or off (0). Data is only logged to channels that are active.
  • [Type] Specify the type of media on which the logging should take place. It can be Disk, Tape or FTP to write directly to a remote computer via FTP.
  • [Filename] Specify the name of a file in case of a disk logging, where 05d is replaced by the current run number the same way as for the ODB dump files. In the case of a tape logging, the filename specifies a tape device like /dev/nrmt0 or /dev/nst0 under UNIX or \\.\tape0 under Windows NT.
    • In FTP mode, the filename specifies the access information for the FTP server. It has the following format:

        <host name>, <port number>, <user name>, <password>, <directory>, <file name>
      

      The normal FTP port number is 21 and 1021 for a Unitree Archive like the one used at the Paul Scherrer Institute. By using the FTP mode, a back-end computer can directly write to the archive.

        myhost.my.domain,21,john,password,/usr/users/data,run%05d.mid
      

  • [Format] Specifies the format to be used for writing the data to the logging channel. It can one of the five value: MIDAS, YBOS, ROOT, ASCII and DUMP. The MIDAS and YBOS binary formats Midas format and YBOS format, respectively. The extention for the file name has to match one of the following.
    • .mid for MIDAS
    • .ybs for YBOS
    • .root for ROOT
    • .asc for ASCII
    • .txt for DUMP

• The ASCII format converts events into readable text format which can be easily analyzed by programs which have problems reading binary data. While the ASCII format tries to minimize the file size by printing one event per line, the DUMP format gives a very detailed ASCII representation of the event including bank information, serial numbers etc, it should be used for diagnostics. Consistency of this type of format has to be maintained between the frontend declaration and the logger.

• [ODB Dump] Specifies the complete dump of the ODB to the logging channel before and after every run. The ODB content is dumped in one long ASCII string reflecting the status at begin-of-run event and at end-of-run event. These special events have an ID of EVENT_ID_BOR and EVENTID_EOR and a serial number equals to the current run number. An analyzer in the off-line analysis stage can restore the ODB to its online state.

• [Log messages] This is a bit-field for logging system messages. If a bit in this field is set, the according system message is written to the logging channel as a message event with an ID of EVENT_ID_MESSAGE (0x8002). The bits are 1 for error, 2 for info, 4 for debug, 8 for user, 16 for log, 32 for talk, 64 for call messages and 255 to log all messages. For an explanation of these messages refer to Buffer Manager, Event ID and Trigger .

• [Mask] Specify which events to log. See Frontend code to learn how events are selected by their ID and trigger mask. To receive all events, -1 is used for the event ID and the trigger mask. By using a buffer other than the "SYSTEM" buffer, event filters can be realized. An analyzer can request all events from the "SYSTEM" buffer, but only write acceptable events to a new buffer called "FILTERED". When the logger request now only events from the new buffer instead of the "SYSTEM" buffer, only filtered events get logged.

• [Event limit, Byte limit and Tape capacity] These fields can be used to stop a run when set to a non-zero value. The statistics values Events written, Bytes written and Bytes written total are checked respectively against these limits. When one of these condition is reached, the run is stopped automatically by the logger. Updates of the statistics branch is performed automatically every so often. This branch contains the number of events and bytes written. These two keys are cleared at the beginning of each run. The Bytes written total and Files written keys are only reset when a tape is rewound with the ODBEdit command rewind. The Bytes written total entry can therefore be used as an indicator if a tape is full. The Files written entry can be used off-line to determine how many files on tape have to be skipped in order to reach a specific run.

• [Subdir format, Current filename] In the case the Subdir format is not empty, this field will enable the placement of the data log file into a sub directory. The name of this subdirectory is composed by the given Subdir format string. Its format follows the definition of the system call strftime() . Ordinary characters placed in the format string are copied to s without conversion. Conversion specifiers are introduced by a `%' character, and are replaced in s as follows for the most used one:
  • Y : Year (ex: 2002)
  • y : Year (range:00..99)
  • m : Month (range: 01..12)
  • d : Day (range: 00..31) The other characters are: a, A, b, B, c, C, d, D, e, E, G, g, h, H, I, j, k, l, m, M, n, O, p, P, r, R, s, S, t, T, u, U, V, w, W, x, X, y, Y, z, Z, +, %. (See man strftime() for explanations).

• [Current filename] will reflect the full path of the saved data file.

---

ODB /Experiment Tree

Under this tree, the Midas system stores special features for the user in order to facilitate his job on controlling a run. Initially only one empty key is defined labeled Name for the experiment name. The user can create four system keys in order to provide extra run control flexibility i.e.: "Run Parameter/", "Edit on Start/", "Lock when running/" and "Security/".

• 2.0.0, this directory can specify the event buffer size for each buffer involved in the experiment. By default the event buffer is named SYSTEM. Its default size is 2MB. This new parameter may be required to optimize the memory usage at the frontend level in case large data transfer is needed. This method work for all MIDAS buffers, except for ODB, where the size has to be specified at creation time using the odbedit command "-s" argument. There is no need to increase the SYSMSG.SHM buffer as it is used only for messages.
  1. Shutdown all MIDAS programs, delete the old .SYSTEM.SHM files sitting in the directory specified by either the exptab or $MIDAS_DIR, use ipcrm for share memory segment removal.
  2. Run odbedit, go to experiment, create a directory key "Buffer Sizes", create a DWORD key of the buffer name to be increased.

       C:\online>odbedit
       [local:Default:S]/>cd Experiment/
       [local:Default:S]/Experiment>mkdir "Buffer Sizes"
       [local:Default:S]/Experiment>cd "Buffer Sizes/
       [local:Default:S]Buffer Sizes>create DWORD SYSTEM
       [local:Default:S]Buffer Sizes>set SYSTEM 4000000
     

  3. Starts the rest of the MIDAS programs. Check that the buffer has the correct size by looking at the size of .SYSTEM.SHM (unix, ipcs), SYSTEM.SHM (windows).
     

     Key name                        Type    #Val  Size  Last Opn Mode Value
     ---------------------------------------------------------------------------
     Experiment                      DIR
         Name                        STRING  1     32    22s  0   RWD  chaos
         Run Parameter               DIR
             Beam Polarity           STRING  1     256   2h   0   R    negative
             Beam Momentum           FLOAT   1     4     2h   0   R    91
             2LT: log file name?     STRING  1     256   2h   0   R    cni05
             1LT: file name?         STRING  1     256   2h   0   R    files.cni.zero
             Comment                 STRING  1     256   2h   0   R    ch2 target
             Target Angle            FLOAT   1     4     2h   0   R    0
             Target Material         STRING  1     256   2h   0   R    ch2
         Edit on start               DIR
             Beam Momentum           FLOAT   1     4     2h   0   R    91
             Beam Polarity           STRING  1     256   2h   0   R    negative
             Target Material         STRING  1     256   2h   0   R    ch2
             Target Angle            FLOAT   1     4     2h   0   R    0
             1LT: file name?         STRING  1     256   2h   0   R    files.cni.zero
             Trigger 2               BOOL    1     4     2h   0   RWD  n
             2LT: log file name?     STRING  1     256   2h   0   R    cni05
             Comment                 STRING  1     256   2h   0   R    ch2 target
             Write data              BOOL    1     4     2h   0   RWD  y
         Lock when running           DIR
             Run Parameter           DIR
                 Beam Polarity       STRING  1     256   2h   0   R    negative
                 Beam Momentum       FLOAT   1     4     2h   0   R    91
                 2LT: log file name? STRING  1     256   2h   0   R    cni05
                 1LT: file name?     STRING  1     256   2h   0   R    files.cni.zero
                 Comment             STRING  1     256   2h   0   R    ch2 target
                 Target Angle        FLOAT   1     4     2h   0   R    0
                 Target Material     STRING  1     256   2h   0   R    ch2
         Security                    DIR
             Password                STRING  1     32    16h  0   RWD  #@D&%F56
             Allowed hosts           DIR
                 host.sample.domain  INT     1     4     >99d 0   RWD  0
                 pierre.triumf.ca    INT     1     4     >99d 0   RWD  0
                 pcch02.triumf.ca    INT     1     4     >99d 0   RWD  0
                 koslx1.triumf.ca    INT     1     4     >99d 0   RWD  0
                 koslx2.triumf.ca    INT     1     4     >99d 0   RWD  0
                 vwchaos.triumf.ca   INT     1     4     >99d 0   RWD  0
                 koslx0.triumf.ca    INT     1     4     >99d 0   RWD  0
             Allowed programs        DIR
                 mstat               INT     1     4     >99d 0   RWD  0
                 mhttpd              INT     1     4     >99d 0   RWD  0
             Web Password            STRING  1     32    16h  0   RWD  pon4@#@%SSDF2
         Name                        STRING  1     32    4m   0   RWD  Default
         Buffer Sizes                DIR
             SYSTEM                  DWORD   1     4     4m   0   RWD  4000000
     

• [Name] Specifies the name of the experiment.
• [Run Parameters] Specifies a fix directory name where you can create and define keys which can be presented at Run start for run condition selection. The actual activation of any of those line is done via a "logical link key" defined in the Edit on Start/ sub-tree. The links don't have to point to run parameters necessarily. They can point to any ODB key including the logger settings. It can make sense to create a link to the logger setting which enables/disables writing of data. A quick test run can then be made without data logging for example:

    [local]/>create key "/Experiment/Run parameters"
  

  Then one or more run parameters can be created in that directory,

    [local]Run parameters>create int "Run mode"
    [local]Run parameters>create string Comment
  

• [Edit on Start] Specifies a fix directory name where you can define an ODB link (similar to a symbolic link in UNIX) key to the pre-defined directory Run Parameters. Any link key present in this directory pointing to a valid ODB key will be requested for input during the run start procedure.
  A new feature has been added to this section for the possibility of preventing the user to change the run number from the web interface during the start sequence. By defining the key /Experiment/Edit on Start/Edit run number as a boolean variable the ability of editing the run number is enabled or disabled. By default if this key is not present the run number is editable.
  

    [local]/>create key "Experiment/Edit on start"
    [local]/>cd "Experiment/Edit on start"
    [local]/>ln "/Experiment/Run parameters/Run mode" "Run mode"
  

  When a run is started from ODBEdit, all links in /Experiment/Edit on start are scanned and read in:

    [local]/>start
    Run mode [0]:1
    Run number [3]:<return to accept>
    Are the above parameters correct?
    ([y]/n/q): <return to accept "y">
    Starting run #2
    Run #2 started
  

    [local]/>cd "Experiment/Edit on start"
    [local]/>create BOOL "Edit run number"
  

• [Lock when running] Specifies a fix directory for defining logical link keys to be set in Read only access mode while the run is in progress. The lock when running can contains logical link to key(s) for setting these keys protection to "read only" while running. In the example below, all the parameters under the declared tree will be switched to read only preventing any parameters modification during the run.

    [local]/>create key "Experiment/Lock when running"
    [local]/>cd "Experiment/Lock when running"
    [local]/>ln "/Experiment/Run parameters" "Run parameter"
    [local]/>ln "/Logger/Write Data" "Write Data?"
  

• [Security] Specifies a fix directory name where information regarding security can be setup. By default, there is no restriction for user to connect locally or remotely to a given experiment. If an access restriction has to be setup in order to protect the experiment from unwilling access, a password mechanism has to be defined. This directory is automatically created when the command passwd is issued in ODB (see below).
• [Password] Specifies the encrypted password for accessing current experiment.

    [local]/>passwd
    Password:<xxxx>
    Retype password:<xxxx>
  

  To remove the full password checking mechanism, the ODB security sub-tree has to be entirely deleted using the following command:

    [local]/>rm /Experiment/Security
    Are you sure to delete the key
    "/Experiment/Security"
    and all its subkeys? (y/[n]) y
  

  After running the odb command passwd, four new sub-fields will be present under the Security tree.
  • Password
  • Allowed hosts
  • Allowed programs
  • Web Password
• [Allowed hosts] Specifies a fix directory name where allowed remote hostname can be defined for free access to the current experiment. While the access restriction can make sense to deny access to outsider to a given experiment, it can be annoying for the people working directly at the back-end computer or for the automatic frontend reloading mechanism (MS-DOS, VxWorks configuration). To address this problem specific hosts can be exempt from having to supply a password and being granted of full access.

    [local]/>cd "/Experiment/Security/Allowed hosts"
    [local]rhosts>create int myhost.domain
    [local]rhosts>
  

  Where <myhost>.<domain> has to be replaces by the full IP address of the host requesting full clearance.
• [Allowed programs] Specifies a list of programs having full access to the ODB independently of the node they running from.

    [local]/>cd "/Experiment/Security/Allowed programs"
    [local]:S>create int mstat
    [local]:S>
  

  
  
  
• [Web Password] Specifies a separate password for the Web server access (mhttpd task ). If this field is active, the user will be requested to provide the "Web Password" when accessing the requested experiment in a "Write Access". In all condition the Read Only Access" is available.

---

ODB /History Tree

This tree is automatically created when the logger is started. The logger will create a default sub-tree containing the following structure:

[local:midas:S]/History>ls -l -r
Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
History                         DIR
    Links                       DIR
        System                  DIR
    Trigger per sec.    /Equipment/Trigger/Statistics/Events per sec.
    Trigger kB per sec. /Equipment/Trigger/Statistics/kBytes per sec.

[local:midas:S]/>cd /History/Links/System/
[local:midas:S]System>ls -l
Key name            Type  #Val Size Last Opn Mode Value
-----------------------------------------------------------
Trigger per sec.    LINK  1    46   >99d 0   RWD  /Equipment/Trigger/Statistics/Events per sec.
Trigger kB per sec. LINK  1    46   >99d 0   RWD  /Equipment/Trigger/Statistics/kBytes per sec.

A second sub-tree is added to the /History by the mhttpd task Midas web server when the button "History" on the main status page is pressed.

[local:midas:S]/History>ls -l -r Display
Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
Display                         DIR
  Default                       DIR
    Trigger rate                DIR
        Variables               STRING  2     32    36h  0   RWD
                                        [0]             System:Trigger per sec.
                                        [1]             System:Trigger kB per sec.
        Factor                  FLOAT   2     4     36h  0   RWD
                                        [0]             1
                                        [1]             1
        Timescale               INT     1     4     36h  0   RWD  3600
        Zero ylow               BOOL    1     4     36h  0   RWD  y

This define a default history display under the Midas web server as long as the reference to "System" is correct. See History system for more information regarding explanation on these fields.

Where the 2 trigger fields are symbolic links to the given path. The sub-tree System defines a "virtual" equipment and get by the system assigned a particular "History Event ID".

---

ODB /Alarms Tree

This branch contains system information related to alarms. Currently the overall alarm is checked once every minute. Once the alarm has been triggered, the message associated to the alarm can be repeated at a different rate. The structure is split in 2 sections. The "Alarms" itself which define the condition to be tested and the "Classes" which defines the action to be taken when the alarm occurs. In order to make the system flexible, beside some default message logging (Classes/Write system message), each action may have a particular "detached script" spawned by it (Classes/Execute command).

odb -e expt -h host
[host:expt:Stopped]/Alarms>ls -lr
Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
Alarms                          DIR
    Alarm system active         BOOL    1     4     6h   0   RWD  n
    Alarms                      DIR
        Test                    DIR
            Active              BOOL    1     4     31h  0   RWD  n
            Triggered           INT     1     4     31h  0   RWD  0
            Type                INT     1     4     31h  0   RWD  3
            Check interval      INT     1     4     31h  0   RWD  60
            Checked last        DWORD   1     4     31h  0   RWD  0
            Time triggered firstSTRING  1     32    31h  0   RWD  
            Time triggered last STRING  1     32    31h  0   RWD  
            Condition           STRING  1     256   31h  0   RWD  /Runinfo/Run number > 10
            Alarm Class         STRING  1     32    31h  0   RWD  Alarm
            Alarm Message       STRING  1     80    31h  0   RWD  Run number became too large
        wc3_anode               DIR
            Active              BOOL    1     4     31h  0   RWD  n
            Triggered           INT     1     4     31h  0   RWD  0
            Type                INT     1     4     31h  0   RWD  3
            Check interval      INT     1     4     31h  0   RWD  10
            Checked last        DWORD   1     4     31h  0   RWD  958070825
            Time triggered firstSTRING  1     32    31h  0   RWD  
            Time triggered last STRING  1     32    31h  0   RWD  
            Condition           STRING  1     256   31h  0   RWD  /equipment/chv/variables/chvv[6] < 900
            Alarm Class         STRING  1     32    31h  0   RWD  Alarm
            Alarm Message       STRING  1     80    31h  0   RWD  WC3 Anode voltage is too low 
        chaos                   DIR
            Active              BOOL    1     4     31h  0   RWD  n
            Triggered           INT     1     4     31h  0   RWD  0
            Type                INT     1     4     31h  0   RWD  3
            Check interval      INT     1     4     31h  0   RWD  10
            Checked last        DWORD   1     4     31h  0   RWD  0
            Time triggered firstSTRING  1     32    31h  0   RWD  
            Time triggered last STRING  1     32    31h  0   RWD  
            Condition           STRING  1     256   31h  0   RWD  /Equipment/B12Y/Variables/B12Y[2] < 3000
            Alarm Class         STRING  1     32    31h  0   RWD  Alarm
            Alarm Message       STRING  1     80    31h  0   RWD  CHAOS magnet has tripped.
    Classes                     DIR
        Alarm                   DIR
            Write system messageBOOL    1     4     31h  0   RWD  y
            Write Elog message  BOOL    1     4     31h  0   RWD  n
            System message interINT     1     4     31h  0   RWD  60
            System message last DWORD   1     4     31h  0   RWD  0
            Execute command     STRING  1     256   31h  0   RWD  
            Execute interval    INT     1     4     31h  0   RWD  0
            Execute last        DWORD   1     4     31h  0   RWD  0
            Stop run            BOOL    1     4     31h  0   RWD  n
        Warning                 DIR
            Write system messageBOOL    1     4     31h  0   RWD  y
            Write Elog message  BOOL    1     4     31h  0   RWD  n
            System message interINT     1     4     31h  0   RWD  60
            System message last DWORD   1     4     31h  0   RWD  0
            Execute command     STRING  1     256   31h  0   RWD  
            Execute interval    INT     1     4     31h  0   RWD  0
            Execute last        DWORD   1     4     31h  0   RWD  0
            Stop run            BOOL    1     4     31h  0   RWD  n

• [Alarm system active] Overall Alarm enable flag.
• [Alarms] Sub-tree defining each individual alarm condition.
• [Classes] Sub-tree defining each individual action to be performed by a pre-defined and requested alarm.

---

ODB /Script Tree

This branch permits to invoke scripts from the web page. By creating the ODB tree /Script every entry in that tree will be available on the Web status page with the name of the key. Each key entry is then composed with a list of ODB field (or links). The first ODB field should be the executable command followed by as many arguments as you wish to be passed to the script.

[host::expt:Stopped]/Script>ls
BNMR Hold
Continue
Real
Test
Kill
[host:expt:Stopped]/Script>ls -lr Continue
Key name           Type    #Val  Size  Last Opn Mode Value
----------------------------------------------------------
Continue           DIR
    cmd            STRING  1     128   39h  0   RWD /home/bnmr/perl/continue.pl
    Name           STRING  1     32    28s  0   RWD  bnmr1
    hold           BOOL    1     4     31h  0   RWD  n

---

ODB /Alias Tree

This branch is not present until the user creates it. It is meant to contain symbolic links list to any ODB location. It is used for the Midas web interface where all the sub-trees will appear in the main window. By default the clicking of the button in the web interface will spawn a new frame. To force the display of the alias link in the same frame, a "&" has to be added to the name of the alias.

odbedit
ls
create key Alias       
cd Alias
ln /Equipment/Trigger/Common "Trig Setting" <-- New frame
ln /Equipment/Trigger/Common "Trig Setting&"      <-- Same frame

---

ODB /Elog Tree

This branch describes the Elog settings used through the Midas web server. See mhttpd task for setting up the different Elog page display.

[local:midas:S]/Elog>ls -lr
Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
Elog                            DIR
    Email                       STRING  1     64    25h  0   RWD  midas@triumf.ca
    Display run number          BOOL    1     4     25h  0   RWD  y
    Allow delete                BOOL    1     4     25h  0   RWD  n
    Types                       STRING  20    32    25h  0   RWD  
                                        [0]             Routine
                                        [1]             Shift summary
                                        [2]             Minor error
                                        [3]             Severe error
                                        [4]             Fix
                                        [5]             Question
                                        [6]             Info
                                        [7]             Modification
                                        [8]             Reply
                                        [9]             Alarm
                                        [10]            Test
                                        [11]            Other
                                        [12]            
                                        [13]            
                                        [14]            
                                        [15]            
                                        [16]            
                                        [17]            
                                        [18]            
                                        [19]            
    Systems                     STRING  20    32    25h  0   RWD  
                                        [0]             General
                                        [1]             DAQ
                                        [2]             Detector
                                        [3]             Electronics
                                        [4]             Target
                                        [5]             Beamline
                                        [6]             
                                        [7]             
                                        [8]             
                                        [9]             
                                        [10]            
                                        [11]            
                                        [12]            
                                        [13]            
                                        [14]            
                                        [15]            
                                        [16]            
                                        [17]            
                                        [18]            
                                        [19]            
Buttons                         
                                8h
                                24h
                                3d
                                7d
Host name                       myhost.triumf.ca
    SMTP host                   STRING  1     64    25h  0   RWD  trmail.triumf.ca

• [Email] Defines the Email address for Elog reply.
• [Display run number] Allows to disable the run number display in the Elog entries.
• [Allow delete] Flag for permiting the deletion of Elog entry.
• [Types] Pre-defined types displayed when composing an Elog entry. A maximum of 20 types are available. The list will be terminated by the encounter of the first blank type.
• [Systems] Pre-defined categories displayed when composing an Elog entry. A maximum of 20 types are available. The list will be terminated by the encounter of the first blank type.
• [SMTP host] Mail server address for routing the composed Elog message to the destination.
• [Buttons] Permits to recall up to four possible time span for the Elog command.
• [Host name] Host name.
• [Email <...>] Email address to where the message should be sent when composing it under "Systems" of the type <...>,

---

ODB /Programs Tree

System created tree containing task specific characteristics such as the watchdog and alarm condition. See Alarm System .

Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
Programs                        DIR
    EBuilder                    DIR
        Required                BOOL    1     4     0s   0   RWD  y
        Watchdog timeout        INT     1     4     0s   0   RWD  10000
        Check interval          DWORD   1     4     0s   0   RWD  10000
        Start command           STRING  1     256   0s   0   RWD  mevb -D
        Auto start              BOOL    1     4     0s   0   RWD  n
        Auto stop               BOOL    1     4     0s   0   RWD  n
        Auto restart            BOOL    1     4     0s   0   RWD  n
        Alarm class             STRING  1     32    0s   0   RWD  Alarm
        First failed            DWORD   1     4     0s   0   RWD  0

---

ODB /Lazy Tree

Backup facility Tree. Created with default parameters on the first activation of lazylogger task. This task connects to a defined channel (i.e: Tape). when started. Multiple instance of the program can run contemporary.

Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
Lazy                            DIR
    Tape                        DIR
        Settings                DIR
            Maintain free space(INT     1     4     23h  0   RWD  15
            Stay behind         INT     1     4     23h  0   RWD  -1
            Alarm Class         STRING  1     32    23h  0   RWD  
            Running condition   STRING  1     128   23h  0   RWD  ALWAYS
            Data dir            STRING  1     256   23h  0   RWD  /data_onl/current
            Data format         STRING  1     8     23h  0   RWD  YBOS
            Filename format     STRING  1     128   23h  0   RWD  run%05d.ybs
            Backup type         STRING  1     8     23h  0   RWD  Tape
            Execute after rewindSTRING  1     64    23h  0   RWD  ask_for_tape.sh
            Path                STRING  1     128   23h  0   RWD  /dev/nst0
            Capacity (Bytes)    FLOAT   1     4     23h  0   RWD  4.8e+10
            List label          STRING  1     128   3h   0   RWD  tw0078
            Execute before writiSTRING  1     64    23h  0   RWD  lazy_prewrite.csh
            Execute after writinSTRING  1     64    23h  0   RWD  rundb_addrun.pl
        Statistics              DIR
            Backup file         STRING  1     128   3h   0   RWDE run05627.ybs
            File size [Bytes]   FLOAT   1     4     3h   0   RWDE 2.00176e+09
            KBytes copied       FLOAT   1     4     3h   0   RWDE 2.00176e+09
            Total Bytes copied  FLOAT   1     4     3h   0   RWDE 2.00176e+09
            Copy progress [%]   FLOAT   1     4     3h   0   RWDE 100
            Copy Rate [bytes perFLOAT   1     4     3h   0   RWDE 6.21462e+06
            Backup status [%]   FLOAT   1     4     3h   0   RWDE 4.17034
            Number of Files     INT     1     4     3h   0   RWDE 1
            Current Lazy run    INT     1     4     3h   0   RWDE 5627
        List                    DIR
            TW0076              INT     15    4     3h   0   RWD  
                                        [0]             5575
                                        [1]             5576
                                        [2]             5577

---

ODB /EBuilder Tree

The Event Builder tree is created by mevb task and is placed in the Equipment list.

Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
EBuilder                        DIR
    Settings                    DIR
        Event ID                WORD    1     2     65h  0   RWD  1
        Trigger mask            WORD    1     2     65h  0   RWD  1
        Buffer                  STRING  1     32    65h  0   RWD  SYSTEM
        Format                  STRING  1     32    65h  0   RWD  YBOS
        Event mask              DWORD   1     4     65h  0   RWD  3
        hostname                STRING  1     64    3h   0   RWD  myhost
    Statistics                  DIR
        Events sent             DOUBLE  1     8     3h   0   RWD  653423
        Events per sec.         DOUBLE  1     8     3h   0   RWD  1779.17
        kBytes per sec.         DOUBLE  1     8     3h   0   RWD  0
    Channels                    DIR
        Frag1                   DIR
            Settings            DIR
                Event ID        WORD    1     2     65h  0   RWD  1
                Trigger mask    WORD    1     2     65h  0   RWD  65535
                Buffer          STRING  1     32    65h  0   RWD  YBUF1
                Format          STRING  1     32    65h  0   RWD  YBOS
                Event mask      DWORD   1     4     65h  0   RWD  1
            Statistics          DIR
                Events sent     DOUBLE  1     8     3h   0   RWD  653423
                Events per sec. DOUBLE  1     8     3h   0   RWD  1779.17
                kBytes per sec. DOUBLE  1     8     3h   0   RWD  0
        Frag2                   DIR
            Settings            DIR
                Event ID        WORD    1     2     65h  0   RWD  5
                Trigger mask    WORD    1     2     65h  0   RWD  65535
                Buffer          STRING  1     32    65h  0   RWD  YBUF2
                Format          STRING  1     32    65h  0   RWD  YBOS
                Event mask      DWORD   1     4     65h  0   RWD  2
            Statistics          DIR
                Events sent     DOUBLE  1     8     3h   0   RWD  653423
                Events per sec. DOUBLE  1     8     3h   0   RWD  1779.17
                kBytes per sec. DOUBLE  1     8     3h   0   RWD  0

---

ODB /Custom Tree

Web string for custom web page. Editable ONLY from your Web browser through Custom page .

Key name                        Type    #Val  Size  Last Opn Mode Value
---------------------------------------------------------------------------
WebLtno&                        STRING  1     2976  25h  0   RWD  <multi-line>
<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
<html>
<head>
   <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
   <meta name="GENERATOR" content="Mozilla/4.76 [en] (Windows NT 5.0; U) [Netscape]">
   <meta name="Author" content="Pierre-Andr?Amaudruz">
   <title>Set value</title>
</head>
<body text="#000000" bgcolor="#FFFFCC" link="#FF0000" vlink="#800080" alink="#0000FF">
<form method="GET" action="http://myhost.triumf.ca:8081/CS/WebLtno&">
<input type=hidden name=exp value="ltno">
<center><table CELLSPACING=1 CELLPADDING=1 COLS=3 WIDTH="100%" BGCOLOR="#99FF99" >
<caption><b><font face="Georgia"><font color="#000099"><font size=+2>LTNO
Custom Web Page</font></font></font></b></caption>

<tr BGCOLOR="#FFCC99">
<td><b><font color="#FF0000">Actions: </font></b>
<input type=submit name=cmd value=Status>
<input type=submit name=cmd value=Start>
<input type=submit name=cmd value=Stop>
...
<td BGCOLOR="#66FFFF"><b>Polarity section:</b>
<br>Run#: <odb src="/runinfo/run number">
<br>Run#: <odb src="/runinfo/run number">
<br>Run#: <odb src="/runinfo/run number">
<br>Run#: <odb src="/runinfo/run number" edit=1></td>
</tr>
</table></center>

<img src="http://myhost.triumf.ca:8081/HS/Meterdis.gif?exp=ltno&scale=12h&width=400">
<img src="http://myhost.triumf.ca:8081/HS/Bridge.gif?exp=ltno&scale=12h&width=400">
<b><i><font color="#000099"><a href="http://myhost.triumf.ca/ltno/index.html">
<br>
LTNO help</a></font></i></b>
</body>
</html>

---

Hot Link

It is often desirable to modify hardware parameters like discriminator levels or trigger logic connected to the frontend computer. Given the according hardware is accessible from the frontend code, theses parameters are easily controllable when a hot-link ODB is established between the frontend and the ODB itself.

HotLink process

First the parameters have to be defined in the ODB under the Settings tree for the given equipment. Let's assume we have two discriminator levels belonging to the trigger electronics, which should be controllable. Following commands define these levels in the ODB:

[local]/>cd /Equipment/Trigger/
[local]Trigger>create key Settings
[local]Trigger>cd Settings
[local]Settings>create int level1
[local]Settings>create int level2
[local]Settings>ls

The frontend can now map a C structure to these settings. In order to simplify this process, ODBEdit can be requested to generate a header file containing this C structure. This file is usually called event.h. It can be generated in the current directory with the ODB command make which generates in the current directory the header file experim.h :

[local]Settings>make

Now this file can be copied to the frontend directory and included in the frontend source code. It contains a section with a C structure of the trigger settings and an ASCII representation:

typedef struct {
  INT       level1;
  INT       level2;
  TRIGGER_SETTINGS;

#define TRIGGER_SETTINGS_STR(_name) char *_name[] = {\
"[.]",\
"level1 = INT : 0",\
"level2 = INT : 0",\
"",\
NULL  

This definition can be used to define a C structure containing the parameters in frontend.c:

#include <experim.h>

TRIGGER_SETTINGS trigger_settings;

A hot-link between the ODB values and the C structure is established in the frontend_init() routine:

INT frontend_init()
{
HNDLE hDB, hkey;
TRIGGER_SETTINGS_STR(trigger_settings_str);

  cm_get_experiment_database(&hDB, NULL);

  db_create_record(hDB, 0,
    "/Equipment/Trigger/Settings",
    strcomb(trigger_settings_str));

  db_find_key(hDB, 0,
    "/Equipment/Trigger/Settings", &hkey);

  if (db_open_record(hDB, hkey,
      &trigger_settings,
      sizeof(trigger_settings), MODE_READ,
      trigger_update) != DB_SUCCESS)
    {
    cm_msg(MERROR, "frontend_init",
      "Cannot open Trigger Settings in ODB");
    return -1;
     
  return SUCCESS;

The db_create_record() function re-creates the settings sub-tree in the ODB from the ASCII representation in case it has been corrupted or deleted. The db_open_record() now establishes the hot-link between the settings in the ODB and the trigger_settings structure. Each time the ODB settings are modified, the changes are written to the trigger_settings structure and the callback routine trigger_update() is executed afterwards. This routine has the task to set the hardware according to the settings in the trigger_settings structure.

It may look like:

void trigger_update(INT hDB, INT hkey)
{
  printf("New levels: %d %d",
    trigger_settings.level1,
    trigger_settings.level2);

Of course the printf() function should be replaced by a function which accesses the hardware properly. Modifying the trigger values with ODBEdit can test the whole scheme:

[local]/>cd /Equipment/Trigger/Settings
[local]Settings>set level1 123
[local]Settings>set level2 456

Immediately after each modification the frontend should display the new values. The settings can be saved to a file and loaded back later:

[local]/>cd /Equipment/Trigger/Settings
[local]Settings>save settings.odb
[local]Settings>set level1 789
[local]Settings>load settings.odb

The settings can also be modified from any application just by accessing the ODB. Following listing is a complete user application that modifies the trigger level:

#include <midas.h>

main()
{
HNDLE hDB;
INT   level;

  cm_connect_experiment("", "Sample", "Test",
                        NULL);
  cm_get_experiment_database(&hDB, NULL);

  level = 321;
  db_set_value(hDB, 0,
    "/Equipment/Trigger/Settings/Level1",
    &level, sizeof(INT), 1, TID_INT);

  cm_disconnect_experiment();

The following figure summarizes the involved components:

To make sure a hot-link exists, one can use the ODBEdit command sor (show open records):

 [local]Settings>cd /
[local]/>sor
/Equipment/Trigger/Settings open 1 times by ...

---

History system

The history system is an add-on capability build in the data logger (see mlogger task ) to record information in parallel to the data logging. This information is recorded with a time stamp and saved into "data base file" like for later retrieval. One set of file is created per day containing all the requested history events.

The history is working only if the logger is running, but it is not necessary to have any channel enabled.

The definition of the history event is done through two different means:

• frontend history event: Each equipment has the capability to generate "history data" if the particular history field value is different then zero. The value will reflect the periodicity of the history logging (see The Equipment structure).
• "Virtual History event": Composed within the Online Database under the specific tree "/History/Links" (see ODB /History Tree)

Both definition mode takes effects when the data logger gets a "start run" transition. Any modification during the run is not applied until the next run is started.

• [frontend history event] As mentioned earlier, each equipment can be enabled to generate history event based on the periodicity of the history value (in second!). The content if the event will be completely copied into the history files using the definition of the event as tag names for every element of the event.

The history variable name for each element of the event is composed following one of the rules below:

• [bank event] /equipment/<...>/Variables/<bank name>[] is the only reference of the event, the history name is composed of the bank name follwed by the corresponding index of the element.
• [bank event] /equipment/<...>/Settings/Names <bank_name>[] is present, the history name is composed of the corresponding name found in the "Names <bank_name>" array. The size of this array should match the size of the /equipment/<...>/Variables/<bank name[]> .

  [host:chaos:Running]Target>ls -l -r
  Key name                        Type    #Val  Size  Last Opn Mode Value
  ---------------------------------------------------------------------------
  Target                          DIR
      settings                    DIR
          Names TGT_              STRING  7     32    10h  0   RWD  
                                          [0]             Time
                                          [1]             Cryostat vacuum
                                          [2]             Heat Pipe pressure
                                          [3]             Target pressure
                                          [4]             Target temperature
                                          [5]             Shield temperature
                                          [6]             Diode temperature
      Common                      DIR
            ...
      Variables                   DIR
          TGT_                    FLOAT   7     4     10s  0   RWD  
                                          [0]             114059
                                          [1]             4.661
                                          [2]             23.16
                                          [3]             -0.498
                                          [4]             22.888
                                          [5]             82.099
                                          [6]             40
      Statistics                  DIR
            ...
  

• [fixed event] The names of the individual element under /equipment/<...>/variables/ will be used for the history name composition.
• [fixed event with array] If the /equipment/<...>/Settings/Names[] exists, each element of the array will be referenced using the corresponding name of the /Settings/Names[] array.
• [ODB history event]

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Alarm System

The alarm system is built in and part of the main experiment scheduler. This means no separate task is necessary to beneficate from it, but this feature is active during ONLINE mode ONLY . Alarm setup and activation is done through the Online DataBase. Alarm system includes several other features such as: sequencing control of the experiment. The alarm capabilities are:

• Alarm setting on any ODB variables against threshold parameter.
• Alarm check frequency
• Alarm trigger frequency
• Customizable alarm scheme, under this scheme multiple choice of alarm type can be selected.
• Program control on run transition.

Beside the setup through ODBEdit, the Alarm can also be setup through the Midas web page..

Midas Web Alarm setting display

Midas Web Alarm setting display

Midas Web Alarm Program status display

Internal features - Top - Data format

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Midas DOC Version 1.9.5 ---- PSI Stefan Ritt ----
Contributions: Pierre-Andre Amaudruz - Sergio Ballestrero - Suzannah Daviel - Doxygen - Peter Green - Qing Gu - Greg Hackman - Gertjan Hofman - Paul Knowles - Rudi Meier - Glenn Moloney - Dave Morris - John M O'Donnell - Konstantin Olchanski - Renee Poutissou - Tamsen Schurman - Andreas Suter - Jan M.Wouters - Piotr Adam Zolnierczuk

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