Kepserver is unabled to read Modbus Address of device

[LW_10405940]

Hello,

I have an application where Kepserver EX6 is used to read the present value of a temperature controller (Autonics TF33) which has RS-485 connection. Moxa NPort 5150A acts as gateway for the device to the Kepserver. The diagram of devices are attached. Currently, I have good quality of connection to the modbus address of the device, but reading is 0. Furthermore, in order to get clear picture, inside the NPort Web Console, I set the IP Address to its default (192.168.127.254) and operation mode set to TCP (Device is TCP Client) where destination IP address is the NPort IP Address. Details are attached also. Then, inside the Kepserver, I assign channel as Modbus TCP/IP ethernet with port number as same as written in Moxa (i.e. 502). Then, the modbus address I took from the manual of the device (attached).

Any thought/help on this would be great appreciated. Thank you

[AS_8979397 · Accepted solution]

It looks like the Moxa is acting as a serial converter only, not a protocol converter. If this is the case, you will not want to use the Modbus TCP/IP Ethernet driver, but instead use the Modbus RTU Serial driver with Ethernet encapsulation mode as this would be the proper protocol for the RS-485 devices on the downstream side of the converter.

Best regards,

Andy Servetas
Principal Technical Support Engineer | Kepware Technologies