Question about communications based on modbus tcp.

[lzf neu <lzfneu@live.com>]

Hi,

There are radiation dose monitor devices by using modbus tcp protocol to communicate.

The communications have succeeded to establish by using epics 3.14.12.5, modbusR1-2 combined with asynR4-9 (very old version) many years ago.

Therefore, I want to upgrade to the latest program by using modbusR2-9 combined with asynR4-30 and epics 3.14.12.5.

My settings are the same as the old version of modbusR1-2 in start.cmd file:

drvAsynIPPortConfigure("Koyo3R",  "192.168.1.241:502",0,1,1)
modbusInterposeConfig("Koyo3R",  2,0,2000)

drvModbusAsynConfigure("RD3R",   "Koyo3R",  3, 0, 95, 0, 1160, "rpDevice") # modbusR1-2 version

I noticed that there was a little difference of parameter settings in the command drvModbusAsynConfigure of new version (modbusR2-9). The manual says :"For TCP the slave address is used for the "unit identifier", the last field in the MBAP header.", and the last field in the MBAP header, as i know,  is the slave address (ranging from 1 to 247).   So, i randomly set:

drvModbusAsynConfigure("RD3R",   "Koyo3R",  111, 3, 0, 95, 0, 1160, "rpDevice")  # modbusR2-9 version, I randomly set 111

or:

drvModbusAsynConfigure("RD3R",   "Koyo3R",  0xFF, 3, 0, 95, 0, 1160, "rpDevice")  # use 0xFF to disable the parameter

however, I cannot establish  the communications by using the new version of modbus and I have no idea how to do.

The error messages are as follows:

epics> 2018/01/24 15:19:26.062 drvModbusAsyn::doModbusIO port RD3R is disconnected
2018/01/24 15:19:30.069 drvModbusAsyn::doModbusIO port RD3R error calling writeRead, error=192.168.1.241:502 timeout: Resource temporarily unavailable, nwrite=6/6, nread=0
2018/01/24 15:19:31.229 drvModbusAsyn::doModbusIO port RD3R has I/O error
2018/01/24 15:19:35.234 drvModbusAsyn::doModbusIO port RD3R error calling writeRead, error=192.168.1.241:502 timeout: Resource temporarily unavailable, nwrite=6/6, nread=0

Any help will be appreciated,  and thanks in advance !

Zhefu