11/17/2022 3:01 PM | |
Joined: 11/17/2022 Last visit: 12/29/2022 Posts: 2 Rating: (0) |
Dear all, I have two types of Power Meters that I have to connect to SCADA system using Modbus RTU: - 1) SIMEAS (from 2009, version 04.10.07) - 2) SICAM P50 (brand new, FW ver. 4.24.03) I have successfully established communication with SIMEAS using following setup: * bus address: 6 (tried changing during tests) * baud rate: 9600 (-II-) * parity: N * protocol: Mod RTU I am polling every 1s and getting responses without errors. My computer has RS-232 to 485 converter connected with A & B connected to PM's A (3) and B (8) pins. It works also when I connect other pins (GND, +5Vext). So, then I unpacked the new one - SICAM P50 and tried to use the same working setup (params & cable) but I notice the strange bahaviour: first response coming from PM is ok and I get the measurement (looking the same as in SIMEAS case), but every other response is malformed regarding CRC. I attached the report generated by mbpoll application (on ubuntu 20.04). I tried several different Modbus Master drivers (siemens not included :)) but experienced the same results. First response (ok): <06><03><02><E6><AA><C7><9B> All other responses (CRC malformed): <00><06><03><02><00><96><8D><EA> I noticed that the first byte in malformed packets is always 00 (this is obviously the cause of invalid CRC). If I use the pinout described in P50 documentation (all pins except shield) I do not even get the first answer correct, but if I connect only 2 wires (A & B) I get the first answer at least (others malformed). In the end, I decided to downgrade the FW for P50 and lowered it down from 4.24.03 to 3.11.03. Here are the results: 1) all pins: same behaviour - only CRC errors 2) only A & B pins - ~90% correct answers (still occassional timeouts/CRCs) I have 3 brand new SICAM P50 devices and all are behaving the same. TL;DR ===== Has anyone experienced ModbusRTU communication issues with SICAM P50 using FW 4.24.03? Only first reponse is ok, all others CRC malformed. Could it be related to FW changes? I tried to find FW CHANGELOG but without success. I am now considering the downgrade of all P50 PMs to older FW but do not have info on other FW features/improvements. Attachmentcomm_log.txt (432 Downloads) |
Last edited by: Jen_Moderator at: 11/18/2022 07:48:33Text formatting optimized. |
|
11/28/2022 3:28 PM | |
Joined: 7/7/2010 Last visit: 9/12/2024 Posts: 15180 Rating: (2417) |
Have you tried a mobdbus rtu simulator? This link may help you find a suitable simulator tool: Modbus Master and Slave Simulators – Dale Scott Using a simulator, you can find out if it's a firmware problem on the receiver, the sender, or some noise somehow pushing a NULL between actual data bytes. It could be the serial port configuration is not valid. If it configured for the correct data bits per packet, parity, stop bits, start bits, and all that sort of thing? It might simply be a configuration issue that is not automatically adjusted by your SCADA system.
|
science guy |
|
Follow us on