Experimental Physics and
Industrial Control System

Mark Rivers <[email protected]> · Fri, 16 Nov 2018 03:03:20 +0000

This page says that ACC AC500 communications modules do support Modbus TCP

https://new.abb.com/plc/programmable-logic-controllers-plcs/ac500/communication-modules

It appears that CPU modules with Ethernet support Modbus, as does the CM597 module.

I think that Modbus will always use port 502.  If you are using a different port it is probably a different protocol.

Mark

________________________________
From: [email protected] <[email protected]> on behalf of 黄佳伟 <[email protected]>
Sent: Thursday, November 15, 2018 8:30 PM
To: [email protected]
Subject: modbus connection error to ABB PLC

Hello，
    I want to control an ABB AC500 PLC by EPICS through TCP/IP, so I use modbus support from Mark Rivers. I do a little modifications to "Koyo1.cmd" scripts but things do not go well. PLC can be connected by asyn ip port but it shows "Connection reset by peer" when asyn modbus port connects to registers in PLC. I googled this and is told that the reason may be that response telegrams contain RST signal. This error might be a protocol problem.

As mentioned in documents, this modbus support does not support Siemens PLC. Is ABB PLC also not supported? The default port of AC500 PLC is 1201, not 502，as shown below.  Does this matter?

Thank you for any help,
Jasper

Here are my *.cmd and *.substitutions scripts:

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

dbLoadDatabase("../../dbd/modbus.dbd")
modbus_registerRecordDeviceDriver(pdbbase)

drvAsynIPPortConfigure("AC500","192.168.0.10:1201",0,0,1)
#asynSetOption("AC500", 0, "disconnectOnReadTimeout", "Y")

modbusInterposeConfig("AC500", 0, 5000, 0)

drvModbusAsynConfigure("AC_DW1", "AC500", 0, 4, 0, 1, 0, 100, "AC500")
drvModbusAsynConfigure("AC_DW2", "AC500", 0, 4, 1, 1, 0, 100, "AC500")

asynSetTraceIOMask("AC500", 0, 4)
asynSetTraceIOTruncateSize("AC500", 0, 512)

dbLoadTemplate("abb.substitutions")

iocInit

--------------------------------------------------------------------------------------------------------------

file "../../db/longin.template" {pattern
{P, R, PORT, OFFSET, SCAN,}
{AC500:, DW1, AC_DW1, 0, "I/O Intr",}
{AC500:, DW2, AC_DW2, 0, "I/O Intr",}
}

Here is the iocShell output:

#! ../../bin/linux-x86_64/modbusApp
dbLoadDatabase("../../dbd/modbus.dbd")
modbus_registerRecordDeviceDriver(pdbbase)
drvAsynIPPortConfigure("AC500","192.168.0.10:1201",0,0,0)
#asynSetOption("AC500", 0, "disconnectOnReadTimeout", "Y")
modbusInterposeConfig("AC500", 0, 5000, 0)
drvModbusAsynConfigure("AC_DW1", "AC500", 0, 4, 0, 1, 0, 100, "AC500")
drvModbusAsynConfigure("AC_DW2", "AC500", 0, 4, 1, 1, 0, 100, "AC500")
asynSetTraceIOMask("AC500", 0, 4)
asynSetTraceIOTruncateSize("AC500", 0, 512)
dbLoadTemplate("abb.substitutions")
iocInit
Starting iocInit
############################################################################
## EPICS R3.16.1-DEV
## EPICS Base built Oct 24 2018
############################################################################
2018/11/16 10:22:35.526 drvModbusAsyn::doModbusIO port AC_DW1 error calling writeRead, error=192.168.0.10:1201 read error: Connection reset by peer, nwrite=6/6, nread=0
2018/11/16 10:22:35.580 drvModbusAsyn::doModbusIO port AC_DW2 error calling writeRead, error=192.168.0.10:1201 read error: Connection reset by peer, nwrite=6/6, nread=0
iocRun: All initialization complete
epics>

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System