CJ1 plc comms with E5CN

[raviiyer 0]

Hi I am in the process of trying to communicate with E5CN controller from CJ1 PLC (CPU12) and serial comms unit SCU41 using RS422/485 port. I configured the port to use 'Modbus protocol' and half duplex as I am using 2 wire RS485 method. E5CN has optional comms card and the controller is configured as node 1, and to use 'Modbus'. Other settings as per default. I tried to read memory address 0 without any success. I have used CX-protocol and created a simple read protocol and downloaded to the serial comms unit. Also wrote a PMCR instruction to run the above protocol. I don't have detailed instuctions to write and use Modbus for E5CN, it is possible my trial has few hidden errors. All the available serial instructions are for 'Compobus/F' and I am not sure how to set up serial port to use this protocol. I am not for or against any one protocol and method of communication. I am prepared to use any (Modbus or Compobus/F) one as long as it works. I have to read the actual temp reading (PV) and also need to change setpoint thru serial comms. Is there a booklet or example to follow? (I have already written few protocols and successfully using RS422 and modbus comms to talk from CJ1 to few 'Eurotherm' instruments. But this used full duplex 4 wire style of serial comms) Thanks a lot Ravi

[Nibroc 4]

Ravi, Do you have manual H135-E1-01? This manual describes the communications formats for the E5 series. Perhaps you could post your protocol macro here, this would allow us to take a look at it. Are you using a CJ1W-SCU41, if so the RS422/485 port should be set to 2 wire. To confirm the communications output coming from the PLC you could switch to the RS232 port and connect it to a PC (use a standard host link cable), then monitor with a terminal program (such as hyperterminal). Nibroc...

[BobB 58]

Have you tried this? It works for Modbus. Omron Modbus Protocol Also, sometimes I find word "0" does not work. Try word 1.

[gtsuport 61]

The Modbus Protocol Macro that BobB refers to works very well. I have worked with a couple of customers in the past month that have had very good success with it! The Communication Manual that Nibroc refers to is here: H135 E5_N Comm Manual at Mr.PLC.com I just uploaded it. It is on the European and Asian Omron sites, but for some strange reason, it is NOT on the US website. This manual does give the address information required to make Modbus work. Hope this will help!

[PLCer 0]

E5_N can use Modbus?? Anyone can give me the documentation?

[BobB 58]

Refer to my previous post. You can download Modbus communications software for the SCU there. It comes with documentation.

[gtsuport 61]

PLCer, Please refer to my previous post. The manual link posted there has the documentation. The Modbus protocol was added when the E5_N controllers were updated roughly 18 months ago.