Re: problem reading data from PLC

[Sebastian Marsching via Tech-talk <tech-talk at aps.anl.gov>]

Hi,

in my experience, this kind of has one of three causes:

1. As already mentioned, the address might be invalid. It might make sense to add the address to a watch table in TIA Portal in order to verify that is correct and provides the right value.

2. The parameter passed to s7nodaveConfigureIsoTcpPort might be incorrect. Please ensure that the rack number and slot number match the CPU (again, this information can be found in TIA Portal).

3. The PLC has to be configured to allow access GET/PUT access and protection and optimized block access must be disabled. You can find details (including screenshots of the relevant configuration options in TIA Portal) in the Snap7 documentation, which is the library used by s7nodave: https://snap7.sourceforge.net/snap7_client.html#1200_1500

Best regards,

Sebastian

Am 04.08.2023 um 12:45 schrieb Abhishek Dutta <abhishek.d at vecc.gov.in>:

Sir,

I've been trying to establish communication with S7 1500 PLC. Trying to read IW0, MD0.

While starting the IOC, I don't get any syntax error etc. The message shows following:

#!../../bin/linux-x86_64/myS7

< envPaths

epicsEnvSet("IOC","iocmyS7")

epicsEnvSet("TOP","/ics/tools/myS7")

epicsEnvSet("ASYN","/ics/tools/asyn4-38")

epicsEnvSet("S7NODAVE","/home/training/Desktop/ics/tools/s7nodave-3.0.2")

epicsEnvSet("EPICS_BASE","/ics/tools/base-7.0.6")

epicsEnvSet("ETHER_IP","/ics/tools/ether_ip")

epicsEnvSet("SNCSEQ","/ics/tools/seq-2.2.9")

epicsEnvSet("AUTOSAVE","/ics/tools/autosave-R5-10-2")

epicsEnvSet("STREAM","/ics/tools/StreamDevice-master")

epicsEnvSet("BUSY","/ics/tools/busy-1-6-1")

epicsEnvSet("PVXS","/ics/tools/pvxs")

epicsEnvSet("PYDEVICE","/ics/tools/PyDevice-R1.1.1")

cd "/ics/tools/myS7"

## Register all support components

dbLoadDatabase "dbd/myS7.dbd"

myS7_registerRecordDeviceDriver pdbbase

#var mySubDebug 1

#traceIocInit

cd "/ics/tools/myS7/iocBoot/iocmyS7"

## Load record instances

#dbLoadTemplate "user.substitutions"

#dbLoadRecords "user.db"

< hall.cmd

s7nodaveConfigureIsoTcpPort("HallPLC","192.168.0.1",0,1,0)

s7nodaveConfigurePollGroup("HallPLC",'default',1.0,0)

s7nodaveConfigurePollGroup("HallPLC",'fast',0.1,0)

dbLoadRecords "hall1.db"

iocInit

Starting iocInit

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

## EPICS R7.0.6

## Rev. 2021-09-28T15:27-0400

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

iocRun: All initialization complete

## Start any sequence programs

#seq sncExample, "user=training"

epics> 2023/08/01 21:01:20.281 HallPLC error while reading 2 bytes from PLC address IB0.

2023/08/01 21:01:20.283 HallPLC error while reading 4 bytes from PLC address FB0.

IOC name is myS7 and following is the hall1.db file. It resides in the same st.cmd directory:

record(ai, "hall_ip1")

{

field(SCAN,"1 second")

field(DTYP,"s7nodave")

field(INP, "@HallPLC(DLV=0,DHV=27648) IW0 int16")

field(EGU,"V")

}

record(ai, "hall_uvolt")

{

field(SCAN,"1 second")

field(DTYP,"s7nodave")

field(INP, "@HallPLC MD0 float")

field(EGU,"V")

}

Please suggest solution for the same.

Regards,

अभिषेक दत्ता/Abhishek Dutta
परिवर्ती ऊर्जा साइक्लोट्रॉन केन्द्र/Variable Energy Cyclotron Center
ईमेल/e-mail: abhishek.d at vecc.gov.in

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