iFIX lets you control the startup status of SAC using the task configuration of the SCU.
Starting SAC Automatically
When you enable the SCADA function, the SCU includes WSACTASK.EXE in the startup list within the Task Configuration dialog box. This starts SAC automatically.
If you disable SAC during development, you must enable it again. You can also modify how SAC operates by entering specific command line parameters.
The following command line parameters control how SAC starts and operates:
- Dseconds – Delays SAC processing of the database until the I/O driver initializes and receives data from control devices. By default, SAC automatically delays processing for 8 seconds. You can use the D parameter to specify a delay of 1 to 300 seconds, for example D30, to control initial processing of database blocks.
- C – Suppresses communication (COMM) and No Data (NODATA) alarms. This must be the last parameter for it to work correctly if you are using iFIX v4.5 or earlier.
- UN – Suppresses Under Range (UNDER) alarms.
- U – Suppresses the Over Range (OVER) alarms.
- N – Suppresses No Data (NO_DATA) alarms.
- R – Suppresses Range (RANGE) alarms.
- Wseconds - Enables a warm start delay after a SCADA failover. During the warm start delay period, SAC suppresses driver alarms for the time period specified following a SCADA failover. Once the time period elapses, driver alarms are handled as usual. You can use the W parameter to specify a delay of 1 to 300 seconds. For example, the parameter W30 causes SAC to suppress NODATA and COMM alarms for 30 seconds after a SCADA failover. If the delay is outside the acceptable range, the parameter is ignored and NODATA and COMM alarms are processed as usual after a SCADA failover.
- Qn – Sets the number of SAC alarm queue entries. You can use the Q parameter to specify a value from 1000 to 32767. If the Q parameter is not specified, the default value is 1000 or the size of the Alarm Summary queue, whichever is greater. Setting this parameter too low may result in alarm queue overflow and lost alarms.
- S – Synchronizes SAC to the system clock. Refer to the Building a SCADA System manual for information on scan times and synchronization.
- O - Allows SAC overruns or missed cycles to be displayed in the missed cycles field of the SAC tab in Mission Control. (This parameter is the letter 'O', not a zero.)
Use caution when modifying the following parameters. It is recommended that these parameters be modified only if you are familiar with iFIX block processing and alarming:
- P –Indicates the maximum CPU utilization percentage for WSACTASK.EXE.
- X - Sets the maximum exceptions for SAC.
- AN - The number of alarms to process per alarm rate (sleep rate).
- AR - The alarm rate (sleep rate) between processing a number of alarms.
IMPORTANT: SAC parameters do not use the slash (/) or dash (-) delimiters. Use spaces to enter optional SAC parameters. For example: S D30.
