ISIS PV Guide

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This does not cover the PV naming convention, rather it covers the PVs you need to implement.

The PV naming conventions are described on the PV naming page.

1. For a slow changing value (e.g. a temperature), there needs to be a current value readback, a setpoint and a setpoint readback:

   record(ai, "$(P)TEMP") 
   {
       field(SCAN, "1 second")
       field(DTYP, "stream")
       field(INP,  "@devEuro.proto getCurrentTemp $(PORT)")
       field(PREC, "3")
       field(EGU,  "K")
   }
   
   record(ao, "$(P)TEMP:SP") 
   {
       field(DTYP, "stream")
       field(OUT,  "@devEuro.proto setTempSetpoint $(PORT)")
       field(PREC, "3")
       field(EGU, "K") 
   }
   
   record(ai, "$(P)TEMP:SP:RBV") 
   {
       field(SCAN, "1 second")
       field(DTYP, "stream")
       field(INP,  "@devEuro.proto getTempSetpoint $(PORT)")
       field(PREC, "3")
       field(EGU,  "K")
   }
   

2. For a value that changes instantly (e.g. a trigger level), there needs to be a current value readback, a setpoint and a setpoint readback. However the setpoint readback should be an alias for the readback:

   record(ai, "$(P)TRIG_LVL") 
   {
       field(SCAN, "1 second")
       field(DTYP, "stream")
       field(INP,  "@devHameg_8123.proto getTriggerLevel $(PORT)")
       field(PREC, "3")
       field(EGU,  "V")
   }
   
   record(ao, "$(P:)TRIG_LVL:SP") 
   {
       field(DTYP, "stream")
       field(OUT,  "@devHameg_8123.proto setTriggerLevel $(PORT)")
       field(PREC, "3")
       field(EGU, "V") 
   }
       
   alias("$(P)TRIG_LVL", "$(P)TRIG_LVL:SP:RBV")
   

3. For a toggle-style button (e.g. voltage on/off) where the current setting can be read, use the same format as 2) but with binary records:

   record(bi, "$(P)VOLTAGE_ON") 
   {
       field(SCAN, "1 second")
       field(DTYP, "stream")
       field(INP,  "@devPSU.proto getVoltageOn $(PORT)")
       field(ZNAM, "OFF")
       field(ONAM, "ON")
   }
   
   record(bo, "$(P)VOLTAGE_ON:SP") 
   {
       field(DTYP, "stream")
       field(OUT,  "@devPSU.proto setVoltageOn $(PORT)")
       field(ZNAM, "OFF")
       field(ONAM, "ON")
   }
   
   alias("$(P)VOLTAGE_ON", "$(P)VOLTAGE_ON:SP:RBV")
   

4. For a toggle-style button where the current setting cannot be read or a push-style button (e.g. a reset button), there needs to be a setpoint and, for convenience, an alias for the current value. This allows the value to be set using either PV.

   record(bo, "$(P)RESET:SP") 
   {
       field(DTYP, "stream")
       field(OUT,  "@devMyDevice.proto reset $(PORT)")
       field(ZNAM, "YES")
       field(ONAM, "TRUE")
   }
       
   alias("$(P)RESET:SP", "$(P)RESET") 
   

5. A read-only value (e.g. a status string).

   record(stringin, "$(P)STATUS") 
   {
       field(DTYP, "stream")
       field(INP,  "@devMyDevice.proto getStatus $(PORT)")
       field(SCAN, "1 second")
   }
   

6. For a value(s) which the user wants to review before changing then press a set button (for motor records this can be done via SPMG):

   • XXX - read back
   • XXX:SP - set the value immediately
   • XXX:SP:RBV - the value that the device has as a setpoint
   • XXX:SP_NO_ACTION - don't set the value but wait (this is a temporary value if you restart the IOC it is lost, consider putting autosave on it)
   • XXX:ACTION - when written to with any value take the SP_NO_MOVE and send it to the device
   • XXX:ACTION:SP - when written to with any value take the SP_NO_MOVE and send it to the device
   • XXX:CHANGED - are the setpoint on device and current setpoint different? It is an enum:
     • NO there is no change to apply
     • YES there is a change to apply