Experimental Physics and
Industrial Control System

Mark Rivers <[email protected]> · Tue, 29 Mar 2016 10:51:48 +0000

Hi Zhefu,

I am sending this message again without the embedded images so it is much smaller.  In the future please use cut-and-paste from your IOC output, not screen shots.

It looks to me like your device is accepting the socket connection on port 502, but then it is not responding to the messages that the IOC is sending.  The driver is waiting 2 seconds and not getting any reply from your device.  This is probably for 1 or more of the following 3 reasons:

1) You are not using the correct protocol.  You are using Modbus TCP.  Have you studied the manual for your device carefully and verified that it uses Modbus TCP, and not Modbus RTU?

2) You are not using the correct Modbus function codes.  Are you sure that your device supports functions codes 3 and 16?

3) You are not using the correct Modbus addresses.  Are you sure that your device supports reading 95 words at address 0 and writing 8 words at address 48?

Mark

________________________________
From: lzfneu [[email protected]]
Sent: Tuesday, March 29, 2016 1:40 AM
To: Mark Rivers; [email protected]
Subject: RE: Question about the connection refused

Hi Mark,

Thanks for your respond.

Sorry, I lost to modified the error and re-sent this email, in layer type TCP/IP no delay is needed,
so the command changed as follows:

> modbusInterposeConfig("UCOS123",0,0,0)

The modified input files are as follows:

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

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

# Use the following commands for TCP/IP

#read   Device ID 2
drvAsynIPPortConfigure("UCOS123","192.168.1.125:502",0,0,1)
asynSetTraceIOMask("UCOS123",0,4)
asynSetTraceMask("UCOS123",0,9)

modbusInterposeConfig("UCOS123",0,0,0)

# Read 100 words (1600 bits).  Function code=3.
drvModbusAsynConfigure("read123", "UCOS123", 0, 3, 0, 95, 0, 100,"M22A")

# Write 8 words (128 bits).  Function code=16
drvModbusAsynConfigure("write123", "UCOS123", 0, 16, 48, 8, 0, 1,"M22A")

iocInit

and the the error messages are shown below:
>

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System