TSX IO Scanning problem

[Loordi100n]

Hi all,

Cant get my head around with this.
I have TSX PLC, ETY 4103 card. I have configured I/O scanning, there are few FC'c, few softstarters, HMI, SafetyLogic and all these works just fine. But then I have SIEMENS SENTRON PAC3200, its has IP (ping works etc.), it has ID 255 (no other device has the same), it reads just 2 words, no writing (so its "0"), it should be straight forward thing. But for some reason its on fault. If I connect to Sentron with modbus tester, it works and after that its not on fault anymore on PLC. If I then reboot the system, it will be on fault again. Modbus register is ok. on sentron you can only put IP/Sub/GWay/ choose modbus or seabus, nothn else.
Anyone???

 

[robertkjonesjr]

Can you provide a Wireshark trace from a mirrored port or a true hub (note these are becoming harder to find nowadays) inserted into the system? Grab data right after reboot, so would be in fault, then connect with the PC, and the system would then go healthy. If you can, get the data at the Siemens end. That should show what the issue is as the trace will progress through a fault state then to healthy.

The UnitID really doesn't matter too much with ModbusTCP as the IP address is really used as the destination address. The UnitID is usually used with serial gateways so the incoming Modbus query can be then be routed properly on the serial side, but for a single device that does not gateway, it is usually redundant. There are exceptions to this as some vendors use the UnitID to allow access to different memory areas or different functions on a single device (some drives do this). Not sure if that exists here, but the user manual should tell you which one to use.