The isegHAL library offers a string based application interface - API. The data collection from the iseg high voltage modules is done in background. All communication hand shake is handled by the isegHAL.
This module offers EPICS device support routines to use the isegHAL library within your EPICS applicaitons.
Set pathes to EPICS_BASE and ISEGHAL in configure/RELEASE.local.
The header files from isegHAL are searched in $ISEGHAL and $ISEGHAL/include,
the shared object files in $ISEGHAL and $ISEGHAL/lib.
If the variable CHECK_TIMESTAMPS is defined in configure/RELEASE.local
the device support will check if the isegHAL has updated the corresponding value
within the last 30 seconds. If not the record is set to a TIMEOUT_ALARM.
If you want to cross compile the devIsegHal module, the ISEGHAL variable should
not be defined in configure/RELEASE.local. Instead only define EPICS_BASE in
this file. ISEGHAL should be defined in configure/RELEASE.Common.{T_A} where
{T_A} stands for the target architecture (e.g. linux-arm).
Before loading any records, devIsegHal has to connect to an interface with the isegHalServer daemon. This is done via the IOC shell command
isegHalConnect( "NAME", "INTERFACE" )
NAME is a user defined name, which is internally used to address this interface
while INTERFACE is the actual name of the hardware interface from your operating system
(e.g. "can0" for a CAN interface)
To make a record use devIsegHal, set its DTYP field to "isegHAL".
The INP or OUT link has the form "@OBJECT IF".
Here OBJECT is a fully qualified object string for the item values
provided by the isegHalServer and IF is the name of the interface as used with the
isegHalConnect command mentioned above.
isegHAL provides its own timestamp of the last change of a value (timeStampLastChanged).
To use this timestamp as timestamp of the record, the TSE field has to be set to -2
Example:
record( ai, "ISEG:0:0:2:VoltageMeasure" ) {
field( DTYP, "isegHAL" )
field( INP, "@0.0.2.VoltageMeasure can0" )
field( TSE, "-2" )
}
If the EGU field is not set in the database, the unit-value from the
corresponding IsegItemProperty is copied into this field during initialization.
It is possible that control parameters change during operation. For example, if a trip occures
the corresponding setON bit in the channel control register will be set to 0.
These changes are monitored by devIsegHal through a polling thread.
Each output record (execpt for stringout records) is automatically registered to this thread
and their values are checked for updates on the isegHAL. If a value has changed
the VAL field and timestamp of the record will be set to the new values.
Setting the SCAN field of input records to I/O Intr will also
register these records for the thread monitoring the values in isegHAL.
The thread goes through the list of registered records, checks each for an update, and then waits for 5 seconds. This waiting time can be modified using the IOC Shell Commands
| Record type | isegDataType |
|---|---|
| ai/ao records | R4 |
| bi/bo records | BOOL |
| mbbiDirect records | UI1 & UI4 |
| longin/longout records | UI1 & UI4 |
| stringin/stringout records | STR |
Note: the maximum string length for stringin/out records is limited to 40 characters while the maximal length for the value of an IsegItemValue is 200. Thus only the first 39 characters of the IsegItemValue are copied to record's VAL field (plus Null-Character for string termination).
Currently there is only on command callable from the IOC shell.
devIsegHalSetOpt( "key", "value" )
| Key | Meaning | Value |
|---|---|---|
| Intervall | Change the intervall of the polling thread | a value of 0 means no pause between two iterations of the list |
| LogLevel | Change log level of isegHalServer | see isegHal Manual |