/Alarms ODB tree
Links
Purpose
The ODB /Alarms tree contains user and system information related to alarms (see Alarm System).
Creating the /Alarms tree
When the ODB is created, the /Alarms tree is automatically created, with
- two Alarms with <alarm name> "Demo ODB" and "Demo periodic" and
- two Classes with <class name> "Alarm" and "Warning".
These are shown in the example below.
The user may create other alarms and classes by copying an existing <alarm-name> or <alarm-class> subtree and editing as required.
By default, the Alarm System is NOT active Currently, the overall alarm is checked once every minute. Once the alarm has been triggered, the message associated with the alarm can be repeated at a different rate.
Examples
Default /Alarms tree
This /Alarms tree is shown using odbedit (see also mhttpd Alarm page).
$ odbedit [local:pol:S]/>cd /alarms [local:pol:S]/Alarms>ls Alarm system active y Alarms Classes
[local:pol:S]/Alarms>ls -r -lt
Key name Type #Val Size Last Opn Mode Value
---------------------------------------------------------------------------
Alarms DIR
Alarm system active BOOL 1 4 4h 0 RWD y
Alarms DIR
Demo ODB DIR
Active BOOL 1 4 >99d 0 RWD n
Triggered INT 1 4 >99d 0 RWD 0
Type INT 1 4 >99d 0 RWD 3
Check interval INT 1 4 >99d 0 RWD 60
Checked last DWORD 1 4 >99d 0 RWD 0
Time triggered firstSTRING 1 32 >99d 0 RWD
Time triggered last STRING 1 32 >99d 0 RWD
Condition STRING 1 256 >99d 0 RWD /Runinfo/Run number > 100
Alarm Class STRING 1 32 >99d 0 RWD Alarm
Alarm Message STRING 1 80 >99d 0 RWD Run number became too large
Demo periodic DIR
Active BOOL 1 4 >99d 0 RWD n
Triggered INT 1 4 >99d 0 RWD 0
Type INT 1 4 >99d 0 RWD 4
Check interval INT 1 4 >99d 0 RWD 28800
Checked last DWORD 1 4 >99d 0 RWD 1058817867
Time triggered firstSTRING 1 32 >99d 0 RWD
Time triggered last STRING 1 32 >99d 0 RWD
Condition STRING 1 256 >99d 0 RWD
Alarm Class STRING 1 32 >99d 0 RWD Warning
Alarm Message STRING 1 80 >99d 0 RWD Please do your shift checks
fePOL DIR
Active BOOL 1 4 19s 0 RWD y
Triggered INT 1 4 19s 0 RWD 205
Type INT 1 4 3s 0 RWD 2
Check interval INT 1 4 19s 0 RWD 60
Checked last DWORD 1 4 19s 0 RWD 1259196026
Time triggered firstSTRING 1 32 19s 0 RWD Wed Nov 25 12:59:33 2009
Time triggered last STRING 1 32 19s 0 RWD Wed Nov 25 16:40:26 2009
Condition STRING 1 256 3s 0 RWD Program not running
Alarm Class STRING 1 32 19s 0 RWD Caution
Alarm Message STRING 1 80 19s 0 RWD Program fePOL is not running
Classes DIR
Alarm DIR
Write system messageBOOL 1 4 27h 0 RWD y
Write Elog message BOOL 1 4 27h 0 RWD n
System message interINT 1 4 27h 0 RWD 60
System message last DWORD 1 4 27h 0 RWD 0
Execute command STRING 1 256 27h 0 RWD
Execute interval INT 1 4 27h 0 RWD 0
Execute last DWORD 1 4 27h 0 RWD 0
Stop run BOOL 1 4 27h 0 RWD n
Display BGColor STRING 1 32 27h 0 RWD red
Display FGColor STRING 1 32 27h 0 RWD black
Warning DIR
Write system messageBOOL 1 4 >99d 0 RWD y
Write Elog message BOOL 1 4 >99d 0 RWD n
System message interINT 1 4 >99d 0 RWD 60
System message last DWORD 1 4 >99d 0 RWD 0
Execute command STRING 1 256 >99d 0 RWD
Execute interval INT 1 4 >99d 0 RWD 0
Execute last DWORD 1 4 >99d 0 RWD 0
Stop run BOOL 1 4 >99d 0 RWD n
Display BGColor STRING 1 32 >99d 0 RWD red
Display FGColor STRING 1 32 >99d 0 RWD black
Alarm triggering Email or SMS alerts
It is also possible to have the MIDAS alarm system send email or SMS alerts to cell phones when alarms are triggered. This can be configured by defining an ODB alarm on a critical ODB parameter, e.g.
/Alarms/Alarms/Liquid Level Active y Triggered 0 (0x0) Type 3 (0x3) Check interval 60 (0x3C) Checked last 1227690148 (0x492D10A4) Time triggered first (empty) Time triggered last (empty) Condition /Equipment/Environment/Variables/Input[0] < 10 Alarm Class Level Alarm Alarm Message Liquid Level is only %s
In this example, the alarm triggers an alarm of class "Level Alarm". This alarm class is defined as follows:
/Alarms/Classes/Level Alarm Write system message y Write Elog message n System message interval 600 (0x258) System message last 0 (0x0) Execute command /home/midas/level_alarm '%s' Execute interval 1800 (0x708) Execute last 0 (0x0) Stop run n Display BGColor red Display FGColor black
The key here is to call a script "level_alarm", which can send emails. Use something like:
#/bin/csh echo $1 | mail -s \"Level Alarm\" your.name@domain.edu odbedit -c 'msg 2 level_alarm \"Alarm was sent to your.name@domain.edu\"'
The second command just generates a MIDAS system message for confirmation. Most cell phones (depends on the provider) have an email address. If you send an email there, it will be translated into a SMS message.
The script file above can of course be more complicated. A perl script could be used that parses an address list, so other interested parties can register by adding his/her email address to that list. The script may also collects some other slow control variables (like pressure, temperature) and combine them into the SMS message.
For very sensitive systems, having an alarm via SMS may not be sufficient, since the alarm system could be down (e.g. computer crash, network failure). In this case 'negative alarms' can be used. For example, every 30 minutes the system may send an SMS with the current parameter values. If the expected message is not received, it may indicate that something in the MIDAS system is wrong.
/Alarms tree structure
The Alarms structure is split into 2 sections:
- "Alarms" which define the condition to be tested. The user can create as many Alarms as desired, but each must be one of the four defined Alarm Types .
- "Classes" which define the action to be taken when the alarm occurs. Two Classes (Alarm and Warning) are defined by default. The user can add more Classes as desired.
In order to make the system flexible, each alarm class may perform different actions when an alarm is given. For example, it may
- write a system message (see Write System Message)
- write to the elog (see Write Elog Message)
- stop the run (see Stop run)
- spawn a detached script listed in the ODB variable Execute command. This feature is used when an Alarm triggers Email or SMS alerts (see example).
The four available Alarm Types are shown in Table 1. They are defined in midas.h. The alarm type is entered into the Type key.
| Alarm Type | INT value | Explanation | |
| Internal alarms | AT_INTERNAL | 1 | Trigger on internal (program) alarm setting through the use of the al_...() functions. |
| Program alarms | AT_PROGRAM | 2 | Triggered on condition of the state of the defined task. |
| Evaluated alarms | AT_EVALUATED | 3 | Triggered by ODB value on given arithmetical condition. |
| Periodic alarms | AT_PERIODIC | 4 | Triggered by timeout condition defined in the alarm setting. |
Program Alarm
The Program Alarms are enabled for individual programs by setting Alarm class in the ODB /Programs/<program> subtree. See Alarm System for details.
Periodic Alarm
The periodic alarm is activated periodically according to the time in Check interval. An example of a periodic alarm is "Demp Periodic" in the example above.
Evaluated Alarm conditions
The alarm condition for evaluated alarms is entered into the ODB key Condition in the <alarm_name> subtree. The condition may be simply a comparison between any ODB variable and a threshold parameter, e.g.
/Runinfo/Run number > 100
or it may be an evaluated condition. One can write conditions like
/Equipment/HV/Variables/Input[*] < 100
or
/Equipment/HV/Variables/Input[2-3] < 100
to check all values from an array or a certain range. If one array element fulfills the alarm condition, the alarm is triggerrd. In addition, bit-wise alarm conditions are possible, e.g.
/Equipment/Environment/Variables/Input[0] & 8
The alarm is triggered if bit #2 is set in Input[0].
Internal Alarms
These are triggered in a program using a call to al_trigger_alarm(). See also Alarm System.
Keys in the /Alarms ODB tree
Alarm system active
- Type: BOOL
- Default: "n"
If this key in the /Alarms ODB tree is set to "y", the alarm system is active. Set to "n" to deactivate.
Alarms subtree
- Type: DIR
Sub-tree in the /Alarms ODB tree defining each individual alarm condition.
<alarm-name> subtree
- Type: DIR
This subtree in the /Alarms/alarms subtree specifies the name of one of the defined alarms, where name is substituted for <alarm-name>. This subtree will be repeated with a different name for each defined alarm.
In the example two <alarm-name> subtrees are shown, called "demo odb" and "demo periodic"
Active
- Type: BOOL
- Default: "n"
If this key in the <alarm-name> subtree is set to "y" , this particular alarm is active.
Triggered
- Type: INT
- Default: 0
If this key in the <alarm-name> subtree is non-zero, this alarm has been triggered. Filled by System.
Type
- Type: INT
- Default:
This key in the <alarm-name> subtree must be one of the listed Alarm Types.
Check interval
- Type: INT
- Default: 60
This key in the <alarm-name> subtree contains the
frequency in seconds at which this alarm condition is to be checked by the alarm system.
Checked last
- Type: DWORD
- Default:
This key in the <alarm-name> subtree is written by the Alarm System.
Time triggered first
- Type: STRING
- Default:
This key in the <alarm-name> subtree is written by the Alarm System.
Time triggered last
- Type: STRING
- Default:
This key in the <alarm-name> subtree is written by the Alarm System.
Condition
- Type: STRING
- Default:
This key in the <alarm-name> subtree contains
the condition on which alarm should trigger for evaluated alarms. See #Evaluated Alarm conditions.
Alarm class
- Type: STRING
- Default:
This key in the <alarm-name> subtree is set to one of the existing Alarm classes, e.g. "Alarm","Warning".
The Alarm class must be defined in the Classes subtree.
Alarm message
- Type: STRING
- Default:
This key in the <alarm-name> subtree constains the message to be written when alarm triggers.
Classes subtree
- Type: DIR
Sub-tree in the /Alarms ODB tree defining each individual alarm class. Each class defines the individual action to be performed by a predefined and requested alarm.
<class-name> subtree
- Type: DIR
This subtree in the #Classes subtree defines one of the alarm classes of name name, where name is substituted for <class-name>. This subtree will be repeated with a different name for each defined class. In the example above, two <class-name> subtrees are shown, named "Alarm" and "Warning".
Write System Message
- Type: BOOL
- Default: "y"
If this key in the <class-name> subtree is set to "y", a message will be sent to the System log when an alarm with this alarm class is triggered.
Write Elog Message
- Type: BOOL
- Default: "n"
If this key in the <class-name> subtree is set to "y", a message will be written to the Elog when an alarm with this alarm class is triggered.
System message interval
- Type: INT
- Default: 60
This key in the <class-name> subtree contains the interval in seconds between successive system messages when an alarm with this alarm class is triggered
See also Alarm System#Implementation of the MIDAS Alarm System for note on the implementation of this key by the alarm system.
System message last
- Type: DWORD
- Default: 0
This key in the <class-name> subtree contains the time when the last alarm system message was written. It is filled by the alarm system.
Execute command
- Type: STRING
- Default: ""
This key in the <class-name> subtree may contain a command to be executed when an alarm with this alarm class is triggered. This parameter can be used to trigger Email or SMS alerts.
Execute interval
- Type: INT
- Default: 0
When an alarm with this alarm class is triggered, if a valid Execute command is supplied, the command will be repeated at an interval in seconds designated by this key in the <class-name> subtree, providing the interval set is greater than 0.
Execute last
- Type: DWORD
- Default: 0
This key in the <class-name> subtree contains the time when the alarm system last executed the command in the key Execute command. It is filled by the alarm system.
Stop run
- Type: BOOL
- Default: "n"
This key in the <class-name> subtree if set to "y" will cause the run to stop when an alarm with this alarm class is triggered.
Display BGColor
- Type: STRING
- Default: "red"
This key in the <class-name> subtree contains the background colour of the alarm banner on the mhttpd Status Page. The alarm banner appears if the alarm is triggered.
Display FGColor
- Type: STRING
- Default: "black"
This key in the <class-name> subtree contains the foreground colour of the alarm banner on the mhttpd Status Page. The alarm banner appears if the alarm is triggered.