I need Help with a CompactLogix L35E

[adamFSC]

As Ken mentions, why are you not using EthernetIP? Why involve modbus at all?

All of the software development for the PLC was done expecting to communicate via Modbus protocol. I eventually have to set this up in an OPC server (Standard Automation's Unviersal Server) and all of the development that has already been done in Ignition is expecting Modbus protocol. The server software and physical server itself is thousands of miles/kilometers away from the physical device.

Ewww. 1769-SM2 is a PLC module, but not made by the PLC group. Its really a drive product that can be tricked into working on Modbus RTU.
Apparently, AB drives speak a special version of Modbus RTU (with addresses >128), so somebody decided to sell the 1769-SM2 for a modbus interface.
Read my tome on the AB Knowledgebase, and move with caution.

I now stand corrected. The answer is NO, we cannot use the SM2. We have already pruchased and wired extensively the L35E into the system.

So the only option with the cellular link is RS232 with a Modbus protocol? Are you trying to use the ConnectPort Serial Wireless server? Also, do you have a PC based HMI connected to the Compact Logix running Inductive Automation's Ignition communicating over EIP?

We need to eventually talk to the device through the Internet via Modbus protocol. If there was a way to communicate through to the device via a different protocol and have some software translate that for us, then I am all ears.

I'm not sure if we are using the ConnectPort Digi or not. We had it shipped off to verify it was in good workign condition. I don't think it is because we have 5 ports on our Digi. (We've also tried a Digi IA, but it was not working either.)

We haven't connected to the Compact Logix through Ignition yet. (I've been trying to use ModScan32 to communicate to the device after we got the direct serial link to work with Modbus protocol.) I am planning to try to connect to the PLC through the local network today, by-passing the Digi. Indeed, I still have to make sure all of the HMI in Ignition is working even *after* getting the device talking Modbus across the Internet.

 

[adamFSC]

Thanske to all who responded. The solution will be to use a Digi WAN IA which allows for the tralslation protocol that we need from TCP to RTU. we had it working successfuly through port porting in a Wan Connect Edge and a Digi WAN One IA.