Re: Error "drvModbusAsyn::readPoller ... invalud memory request 3, max=3" of module Eurotherm2k

[LiangChih Chiang via Tech-talk <tech-talk at aps.anl.gov>]

Hi, dear Mark, thanks for replying.

>The Modbus ports are being created with a length of 3+2 (5) and 3+1 (4) registers respectively.  

>The records are reading single registers at offsets of 0, 1, and 2.  

>That should not generate the error you see.

I see. There should be somewhere records access beyond the max length of registers.

And I found the following record access address 4.

record(ai, "$(P)$(Q):WSP:RBV") {
  field(DESC, "Working SP Readback")
  field(DTYP, "asynInt32")
  field(INP, "@asyn(Eurotherm_$(PORT)_$(ADDR)_$(LOOP=1)_Rd_PV,4,1000)MODBUS_DATA")
  field(EGU, "$(EGUT=C)")
  field(SCAN, "I/O Intr")
  field(ASLO, "0.1")
  field(PREC, "1")
}

Thank you again.

It's probably I or my colleague modified the code and forgot.

On Fri, Nov 8, 2024 at 2:55 AM Mark Rivers <rivers at cars.uchicago.edu> wrote:

Hi,

 

I don’t understand why you are getting that error.  The Modbus ports are being created with a length of 3+2 (5) and 3+1 (4) registers respectively.  The records are reading single registers at offsets of 0, 1, and 2.  That should not generate the error you see.

 

Please send the output of:

 

asynReport 2

 

That will show information about all the asyn port drivers and may provide a clue.

 

Mark

 

 

From: Tech-talk <tech-talk-bounces at aps.anl.gov> On Behalf Of LiangChih Chiang via Tech-talk
Sent: Wednesday, November 6, 2024 7:57 PM
To: tech-talk at aps.anl.gov
Subject: Error "drvModbusAsyn::readPoller ... invalud memory request 3, max=3" of module Eurotherm2k

 

Hello, EPICS mates,

 

I use module Eurotherm2k (https://github.com/jwlodek/eurotherm2k)

to access controller Eurothermm 3508.

 

It's ok mostly, but I can't set the P/I/D values.

 

And there are two errors showed repeatedly:

2024/11/07 09:07:35.155 drvModbusAsyn::readPoller port Eurotherm_E3K01_1_1_Rd_PID invalid memory request 3, max=3
2024/11/07 09:07:35.852 drvModbusAsyn::readPoller port Eurotherm_E3K01_1_1_Rd_PV invalid memory request 4, max=3

 

In " E3K01_1_1"

"E3K01" is the port name,

the following "1" is the Modbus address,

then "1" is the loop number.

 

I found that in the file eurothermModbus.c of the module, it calls drvMosbusAsynConfigure:

 

        /* Create modbus channels for the PV, target setpoint and manual output */
        mkname(str, strmaxlen, asynPortName, modbusAddress, loopNumber, 0, "PV");
        asynRet = drvModbusAsynConfigure(str, asynPortName, modbusAddress,
                                MODBUS_READW, loopStart+PV_OFFSET, 3+2,
                                0, EUROTHERM_POLL_MS, "");
        if (asynRet != asynSuccess) {
                LOG_ERROR("drvModbusAsynConfigure failed with error %d", asynRet);
                free(str);
                return -EIO;
        }

        /* Create modbus channels for the PID parameters */
        mkname(str, strmaxlen, asynPortName, modbusAddress, loopNumber, 0, "PID");
        asynRet = drvModbusAsynConfigure(str, asynPortName, modbusAddress,
                                MODBUS_READW, loopStart+PID_OFFSET, 3+1,
                                0, EUROTHERM_POLL_MS, "");
        if (asynRet != asynSuccess) {
                LOG_ERROR("drvModbusAsynConfigure failed with error %d", asynRet);
                free(str);
                return -EIO;
        }

 

And in the file eurothermModbusLoop.template, the records uses the ports created above:

 

# PV: address 1
# % gdatag,pv,ro,$(gda_name=),PVRBV
# % archiver 1 Monitor
record(ai, "$(P)$(Q):PV:RBV") {
  field(DESC, "Temperature Readback")
  field(DTYP, "asynInt32")
  field(INP, "@asyn(Eurotherm_$(PORT)_$(ADDR)_$(LOOP=1)_Rd_PV,0,1000)MODBUS_DATA")
  field(EGU, "$(EGUT=C)")
  field(SCAN, "I/O Intr")
}

# % gdatag,pv,ro,$(gda_name=),SPRBV
# % archiver 10 Monitor
record(ai, "$(P)$(Q):SP:RBV") {
  field(DESC, "Setpoint Readback")
  field(DTYP, "asynInt32")
  field(INP, "@asyn(Eurotherm_$(PORT)_$(ADDR)_$(LOOP=1)_Rd_PV,1,1000)MODBUS_DATA")
  field(EGU, "$(EGUT=C)")
  field(SCAN, "I/O Intr")
  field(ASLO, "0.1")  
}

# % gdatag,pv,ro,$(gda_name=),ORBV
# % archiver 1 Monitor
record(ai, "$(P)$(Q):O:RBV") {
  field(DESC, "Output Readback")
  field(DTYP, "asynInt32")
  field(INP, "@asyn(Eurotherm_$(PORT)_$(ADDR)_$(LOOP=1)_Rd_PV,2,1000)MODBUS_DATA")
  field(EGU, "%")
  field(SCAN, "I/O Intr")
  field(ASLO, "0.1")
  field(PREC, "1")
}

 

Would you please provide some suggestions?