/Experiment ODB tree
Creating the /Experiment tree
The /Experiment ODB tree is created automatically when the ODB is first created.
Purpose
The /Experiment ODB tree contains information relevent to the experiment. Other optional keys are added by mhttpd or by the user to customize their experiment.
Examples
When initially created, the /Experiment tree contains the following keys:
[local:midas:S]/>ls -lrt /experiment
Key name Type #Val Size Last Opn Mode Value
---------------------------------------------------------------------------
Experiment DIR
Name STRING 1 32 14s 0 RWD midas
Buffer sizes DIR
SYSMSG DWORD 1 4 11h 0 RWD 100000
The following example shows the /Experiment tree for a typical experiment :
[local:midas:R]/>ls -lrt /experiment
Key name Type #Val Size Last Opn Mode Value
---------------------------------------------------------------------------
Experiment DIR
Name STRING 1 32 7s 0 RWD midas
Buffer sizes DIR
SYSMSG DWORD 1 4 23h 0 RWD 100000
SYSTEM DWORD 1 4 23h 0 RWD 640000000
BUF0 DWORD 1 4 23h 0 RWD 80000000
BUF1 DWORD 1 4 23h 0 RWD 80000000
....... other user-defined buffers not shown
MAX_EVENT_SIZE DWORD 1 4 23h 0 RWD 4194304
Menu Buttons STRING 1 256 5h 0 RWD Status, ODB, Messages, Elog, Alarms, Programs, History, MSCB, Sequencer, Config, Help
Transition debug flag INT 1 4 23h 0 RWD 0
Transition connect timeout INT 1 4 23h 0 RWD 10000
Transition timeout INT 1 4 23h 0 RWD 120000
edit on start DIR
experiment number DWORD 1 4 2h 0 RWD 9499
field STRING 1 32 2h 0 RWD 19000.2(0.0)G
comment-> /Experiment/run parameters/comment
STRING 1 80 2h 0 RWD Testing with low beam
Number of channels -> /Run Parameters/number of channels
DWORD 1 4 2h 0 RWD 20
Write Data -> /Logger/Write data
BOOL 1 4 2h 0 RWD n
Number of cycles -> /Equipment/FIFO_acq/frontend/hardware/num cycles
DWORD 1 4 2h 0 RWD 0
Parameter Comments DIR
field STRING 1 32 >99d 0 RWD Entered in Tesla unit
Num cycles STRING 1 80 >99d 0 RWD Stop run after num cycles is reached. Enter 0 to disable (free running)
Run Parameters DIR
Comment STRING 1 80 2h 0 RWD Testing with low beam
Run Description STRING 1 256 7h 0 RWD Sequencer Tests
Number of channels DWORD 1 4 2h 0 RWD 20
Lock when running DIR
Num channels -> /Run Parameters/number of channels
DWORD 1 4 2h 0 RWD 20
edit on sequence DIR
title STRING 1 128 2h 0 RWD none
experiment number DWORD 1 4 2h 0 RWD 9438
experimenter STRING 1 32 2h 0 RWD gls
sample STRING 1 36 2h 0 RWD NA
run description -> /Experiment/run parameters/run description
STRING 1 256 7h 0 RWD Sequencer Tests
Write Data -> /Logger/Write data
BOOL 1 4 2h 0 RWD n
Number of cycles -> /Equipment/FIFO_acq/frontend/hardware/num cycles
DWORD 1 4 2h 0 RWD 0
Prevent start on alarms BOOL 1 4 22h 0 RWD n
Prevent start on required BOOL 1 4 22h 0 RWD n
Status items DIR
Experiment Name -> /Experiment/Name
STRING 1 32 7s 0 RWD midas
Start-Stop Buttons BOOL 1 4 5h 0 RWD y
Pause-Resume Buttons BOOL 1 4 5h 0 RWD n
Keys in /Experiment tree
The keys in the ODB /Experiment tree are described in the following sections.
Name
- Type: STRING
- Default:
This key in the /Experiment tree contains the name of the experiment. Filled automatically when the ODB is created.
Buffer Sizes subtree
- Type: DIR
This key in the /Experiment tree is a subtree to contain the sizes of the
Midas Buffers for the experiment. Created with default values. The sizes can be changed to optimize the memory usage. See Event Buffer Size(s) for details. Other user-defined
buffers may be present (e.g. for event filtering).
SYSMSG
- Type: DWORD
- Default: 100000 Bytes
This key in the /Experiment/Buffer Sizes subtree
contains the size of SYSMSG buffer. This buffer is used for MIDAS messages.
SYSTEM
- Type: DWORD
- Default: 8MBytes
This key in the /Experiment/Buffer Sizes subtree
contains the size of SYSTEM buffer. See Event Buffer for details.
MAX_EVENT_SIZE
- Type: DWORD
- Default: 4MBytes
This key in the /Experiment tree specifies the maximum event size that can be acquired. The default value is half the size of the SYSTEM buffer. It can be increased if required (see Event Buffer).
Menu Buttons
- Type: STRING
- Default: "Start, Pause, ODB, Messages, ELog, Alarms, Programs, History, Sequencer, Config, Help"
This key in the /Experiment tree is added automatically by mhttpd to allow the Menu buttons that appear on the Main Status Page to be customized by removing unnecessary buttons or by changing their order. Without the "Pause" being present in the list of menu buttons, the run cannot be paused/resumed, but only started/stopped. This is required by some experiments.
If MSCB support is built into MIDAS, the MSCB Menu button will also be shown.
Transition debug flag
- Type: INT
- Default: 0
This key in the /Experiment tree contains a flag that, if set to 1, causes messages reporting transition progress to be output.
Transition connect timeout
- Type: INT
- Default: 10000
This key in the /Experiment tree contains the
value of timeout for remote rpc connect
Transition timeout
- Type: INT
- Default: 120000
This key in the /Experiment tree constains the
value of timeout for transition
Prevent start on alarms
- Type: BOOL
- Default: "n"
This key in the /Experiment tree if set true will prevent the run from starting if an alarm is true, i.e. the run start procedure will fail if an alarm has been Triggered for a client, provided a valid alarms class has been entered in the client's Alarm class key.
Prevent start on required program
- Type: BOOL
- Default: "n"
This key in the /Experiment tree if set true ("y")
will prevent the run from starting if one of the required clients is not running. A client is flagged as "required" by setting the ODB key
Required to "y".
Start-Stop Buttons
- Type: BOOL
- Default: "y"
By default Start/Stop buttons are shown on the mhttpd main status page. These buttons can be suppressed by setting
this key in the /Experiment tree FALSE.
Pause-Resume Buttons
- Type: BOOL
- Default: "n"
By default Pause/Resume buttons are shown on the mhttpd main status page. These buttons can be suppressed by setting
this key in the /Experiment tree FALSE.
Edit on Start subtree
- Type: DIR
This optional subdirectory in the /Experiment tree may contain user-defined parameters which will be displayed for editing at the beginning of each run. See Edit-on-start Parameters for details.
Parameter Comments subtree
- Type: DIR
This optional subdirectory in the /Experiment tree may contain user-defined parameter comments that give more information about the Edit-on-start Parameters.
Status items subtree
- Type: DIR
This key in the /Experiment tree is a subtree which by default contains a link to the experiment name. Any links or keys
created by the user in this optional subdirectory will be displayed on the mhttpd main status page.
Lock when running subtree
- Type: DIR
This optional subdirectory in the /Experiment tree contains user-defined links to ODB parameters to prevent them being changed when the run is in progress. See Lock when running for details.
Security subtree
- Type: DIR
This optional subtree in the /Experiment tree is created when the odbedit commands passwd or webpasswd are issued. It enables a user to set up security features. See Security
Password
- Type: STRING
- Default:
This key in the /Experiment/Security subtree contains the encrypted password. This Key is created when the odbedit command passwd is issued. See security for details.
- Note
Do not set this key except through the odbedit command passwd. Setting an unencrypted password will lock you out of the ODB unless odbedit is listed as an allowed program.
Allowed hosts subtree
- Type: DIR
This subtree in the /Experiment/Security subtree is created when the odbedit command passwd is issued. When created, this subtree is empty. Optionally, it may contain user-defined names of remote hosts allowed to have free access (i.e. without password) to the current experiment. See allowed hosts.
Allowed programs subtree
- Type: DIR
This subtree in the /Experiment/Security subtree is created when the odbedit command passwd is issued. When created, this subtree is empty. Optionally, it may contain user-defined names of clients allowed to have free access (i.e. without password) to the current experiment. See allowed clients.
Web Password
- Type: STRING
- Default:
If web access restriction has been set up, this key in the /Experiment/Security subtree will contain an encrypted password for Web server access. This key is created by using the odbedit command webpasswd.
If this key is present, the user will be requested to provide the "Web Password" when accessing the requested experiment in "Write Access" mode. The "Read Only Access" mode is still available (without a password) to all users.
Edit on Sequence subtree
- Type: DIR
This optional subdirectory in the /Experiment tree may contain user-defined parameters which will be displayed for editing at the start of each Sequence. See Edit-on-Sequence Parameters for details.