Experimental Physics and
Industrial Control System

[email protected] · Mon, 13 Sep 2010 14:56:58 -0700 (PDT)

Hey everyone, 

I'm having a problem with a calcout record that seems to process before it has passed control to its input record(s). I have a database with two records, 

record(calc, "Current:Coil") {
  field(DESC, "Coil Current")
  field(SCAN, "Passive")
  field(MDEL, ".1")
  field(ADEL, ".1")
  field(INPA, "Current:Coil.VAL  NPP")
  field(INPB, "$(MUX)VOLT:Chan203.VAL  PP MS")
  field(CALC, "A + B")
  field(PINI, "NO")
  field(EGU, "A")	
  field(SDIS, "0")
}

record(calcout, "Voltage:Output") {
  field(DESC, "Output Voltage")
  field(SCAN, "Passive")
  field(INPA, "Current:Coil.VAL  PP MS")
  field(OOPT, "Every Time")
  field(DOPT, "Use CALC")
  field(CALC, "A")
  field(OUT, "$(VLTPROG)P25V.VAL PP MS")
  field(PINI, "YES")
  field(EGU, "V")	
  field(SDIS, "0")

}

and when I start my ioc, I get: 

Starting iocInit
############################################################################
## EPICS R3.14.11 $R3-14-11$ $2009/08/28 18:47:36$
## EPICS Base built Sep  2 2010
############################################################################
2010/09/13 14:37:11.593 172.25.100.69:1234 write 32
MEAS:VOLT:DC? (@203)\n++read eoi\n
2010/09/13 14:37:11.593 172.25.100.97:1234 write 25
APPL P25V, 0.000000, 0.1\n

iocRun: All initialization complete
## Start any sequence programs
#seq sncxxx,"user=andrewwagnerHost"

epics> 2010/09/13 14:37:11.870 172.25.100.69:1234 read 16
+8.92303000E-04\n

It seems the calcout record processes at init (as desired) passes control to input A which issues the MEAS:VOLT:DC? command but doesn't wait for input A to actually return a value. Input A returns control to the calcout record too quickly so if I print the record I get: 

epics> dbpr Voltage:Output
A: 0                ASG:                B: 0                C: 0                
CALC: A             D: 0                DESC: Output Voltage                    
DISA: 0             DISP: 0             DISV: 1             DLYA: 0             
E: 0                F: 0                G: 0                H: 0                
I: 0                J: 0                K: 0                L: 0                
NAME: Voltage:Output                    OCAL: 0             OEVT: 0             
OVAL: 0             POVL: 0             PVAL: 0             SEVR: INVALID       
STAT: LINK          TPRO: 0             VAL: 0              

with an INVALID LINK. How can I guarantee that control from the input is not passed back to the calcout record until it has finished measuring the voltage? Should I set SDIS "Current:Coil.PACT" ? Thanks very much for your help. 

Andrew

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System