Re: PyDevice modbus

[Mark Rivers via Tech-talk <tech-talk at aps.anl.gov>]

Hi  Xiaomin,

> Because the register address of the values not continuous, so I did not use the Modbus module under EPICS,

Beginning with Modbus R2-9 (August 23, 2016) there is support for "absolute" Modbus addressing, so it works fine even if the register addresses are not continuous.  So there is no reason not to us the EPICS modbus module.

Mark

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of liuxiaomin via Tech-talk <tech-talk at aps.anl.gov>
Sent: Friday, July 22, 2022 1:14 AM
To: Smith, Martin via Tech-talk <tech-talk at aps.anl.gov>
Subject: PyDevice modbus

 

Hi,

I am trying to control a device which can get the temperature values ,Because the register address of the values not continuous, so I did not use the Modbus module under EPICS, but used modbus_tk under python to get the value. In order to match with EPICS, I used the support module PyDevice which is an EPICS device support for Python interpreter, When I run the st.cmd file, the following error occurs, So now there are three files, the db file, the st.cmd file and the wave.py file that gets the temperature data.

 

The db files is as flollows:

record(ai, "$(user):GETDATA")

{

   field(DTYP, "pydev")

   field(INP,"@temp1.getData()")

   field(SCAN, "1 second")

}

 

record(waveform, "$(user):TEMP")

{

   field(DTYP, "pydev")

   field(INP, "@pydev.iointr('temp_sent')")

   field(SCAN, "I/O Intr")

   #field(INP, "@temp1.temp_array")

   field(NELM, "1000")

   field(FTVL, "DOUBLE")

}

 

The st.cmd files is as follows:

#!../../bin/linux-x86_64/waveioc

< envPaths

epicsEnvSet("EPICS_CA_SERVER_PORT", 5070)

epicsEnvSet("IOCNAME","waveioc")

cd "${TOP}"

## Register all support components

dbLoadDatabase "dbd/waveioc.dbd"

waveioc_registerRecordDeviceDriver pdbbase

drvModbusAsynConfigure("WORDIR","CAT1",slaveAddress,modbusFunction,modbusStartAddr,modbusLen,dataType,posMsec,"plcType")

pydev("import sys; sys.path.insert(0,'${PWD}')")

pydev("import modbus_tk")

pydev("from wave import Temp")

pydev("temp1 = Temp('192.168.0.11','502')")

dbLoadRecords "db/dbWaveform.db", "user=${IOCNAME}"

cd "${TOP}/iocBoot/${IOC}"

iocInit

 

I encounter a problem, the obtained temperature values are all 0, the real temperature are not 0. If only used  modbus_tk without PyDevice, there is no such error, and can caget the real temperature .

 

caget   waveioc:TEMP

waveioc:TEMP   0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 

 

When the command file runs, it shows:

#!../../bin/linux-x86_64/waveioc

< envPaths

epicsEnvSet("IOC","waveioc")

epicsEnvSet("TOP","/home/iocusr/xm/waveioc")

epicsEnvSet("MODULES","/opt/epics/base/../modules")

epicsEnvSet("AUTOSAVE","/opt/epics/base/../modules/autosave-R5-7-1")

epicsEnvSet("ASYN","/opt/epics/base/../modules/asyn-R4-41")

epicsEnvSet("BUSY","/opt/epics/base/../modules/busy-1-6-1")

epicsEnvSet("CALC","/opt/epics/base/../modules/calc-R3-7-4")

epicsEnvSet("CAPUTLOG","/opt/epics/base/../modules/caPutLog-3-5")

epicsEnvSet("IOCSTATS","/opt/epics/base/../modules/iocStats-3-1-16")

epicsEnvSet("MODBUS","/opt/epics/base/../modules/modbus-R3-2")

epicsEnvSet("NETDEV","/opt/epics/base/../modules/netDev-1-0-6")

epicsEnvSet("PC-MONITOR","/opt/epics/base/../modules/PC-MONITOR1-0-2")

epicsEnvSet("PROCSERVCONTROL","/opt/epics/base/../modules/procServControl-1-9")

epicsEnvSet("S7NODAVE","/opt/epics/base/../modules/s7nodave-2-1-3")

epicsEnvSet("S7PLC","/opt/epics/base/../modules/s7plc")

epicsEnvSet("SSCAN","/opt/epics/base/../modules/sscan-2-10")

epicsEnvSet("STREAM","/opt/epics/base/../modules/StreamDevice-2-8-9")

epicsEnvSet("SNCSEQ","/opt/epics/base/../modules/seq-2-2-6")

epicsEnvSet("PYDEVICE","/opt/PyDevice")

epicsEnvSet("EPICS_BASE","/opt/epics/base")

epicsEnvSet("EPICS_CA_SERVER_PORT", 5070)

epicsEnvSet("IOCNAME","waveioc")

cd "/home/iocusr/xm/waveioc"

## Register all support components

dbLoadDatabase "dbd/waveioc.dbd"

waveioc_registerRecordDeviceDriver pdbbase

Executing Python code: import pydev

Executing Python code: import builtins

Executing Python code: builtins.pydev=pydev

Executing Python code: import pydev

pydev("import sys; sys.path.insert(0,'${PWD}')")

pydev("import modbus_tk")

Executing Python code: import modbus_tk

Traceback (most recent call last):

  File "<string>", line 1, in <module>

ModuleNotFoundError: No module named 'modbus_tk'

pydev("from wave import Temp")

Executing Python code: from wave import Temp

Traceback (most recent call last):

  File "<string>", line 1, in <module>

  File "/usr/lib/python3.7/wave.py", line 2, in <module>

    import modbus_tk

ModuleNotFoundError: No module named 'modbus_tk'

pydev("temp1 = Temp('192.168.0.11','502')")

Executing Python code: temp1 = Temp('192.168.0.11','502')

Traceback (most recent call last):

  File "<string>", line 1, in <module>

NameError: name 'Temp' is not defined

dbLoadRecords "db/dbWaveform.db", "user=waveioc"

cd "/home/iocusr/xm/waveioc/iocBoot/waveioc"

iocInit

Starting iocInit

############################################################################

## EPICS R7.0.5

## Rev. 2021-09-13T15:44+0800

############################################################################

sevr=info s7plcInit: no stations configured

drvStreamInit: Warning! STREAM_PROTOCOL_PATH not set. Defaults to "."

iocRun: All initialization complete

epics>

 Why can't I get the real temperature value?

 

Thanks

xiaomin