I am attempting to retrieve information from a Siemens soft starter 3RW55 using Modbus RTU protocol. I have successfully connected the 2 wires to the CM PTP module on ET200, and on the other end, to the Modbus RTU module of the 3RW55. The Modbus logic has been implemented through SCL, where I am currently receiving data from a digital meter. However, I am encountering difficulties in receiving any data from the soft starter. Any assistance in resolving this issue would be greatly appreciated. Thank you.
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Have you tried checking the Modbus addresses for the soft starter? It's possible that the addresses could be wrong or conflicting with another device. Another thing to consider is the baud rate - ensure it matches across all devices. If you're still having issues, sometimes a simple power cycle could help or you may need to check your code on SCL for any potential faults. Ensuring your communication settings are correct is key with Modbus RTU. Hope this helps and keep us posted!
This sounds like a precise, yet complex issue. One possiblity could be a disparity in the communication settings. Make sure all your parameters including baud rate, data bits, parity, and stop bits are matching on both ET200 and 3RW55. Also, examine the slave address for the 3RW55 - it must be configured correctly according to your Modbus logic. Sometimes, addressing a specific register which may not exist or an error in function codes could cause trouble. Lastly, consider using a Modbus diagnostic tool (like ModScan) to analyze your network and more specifically, the communication between the two devices. It'll help you to get more insight about the actual problem. Good luck!
It sounds like you've checked all the usual suspects, in terms of wiring and logic setup. However, one thing you might want to investigate is your Modbus RTU mapping. It sounds like your Digital Meter is communicating fine, but the soft starter isn't. This leads me to wonder if there might be some discrepancies in the register mapping. Also, it wouldn't hurt to double-check your baud rate and parity settings between the 3RW55 and ET200. Remember that all devices on the bus should ideally have the same configuration.
It sounds like you're making good progress with your setup! Have you double-checked the Modbus configuration settings on both the ET200 and the 3RW55? It’s important to ensure that parameters like baud rate, parity, and device IDs match perfectly, as even a small mismatch can cause communication issues. Also, confirm that you're using the correct Modbus function codes for the registers you're trying to read from the soft starter. If everything looks good on that end, it might also help to use a Modbus sniffer tool to see if the request is reaching the soft starter and if it's sending a response back. Good luck!
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Answer: 1. Q: How can I troubleshoot communication issues between a Siemens soft starter and Modbus RTU protocol on S7 1500? Check the wiring connections between the CM PTP module on ET200 and the Modbus RTU module of the soft starter. Ensure proper configuration settings and protocols are in place.
Answer: Verify the Modbus logic implemented through SCL for the soft starter and ensure it is correctly configured to communicate with the device. Check for any specific settings required for the soft starter communication.
Answer: Possible issues could include incorrect addressing, mismatched communication parameters, or compatibility problems between the devices. Double-check the configuration and settings for both the soft starter and Modbus RTU module.
Answer: Conduct thorough testing of the communication setup, validate the data exchange process, and troubleshoot any errors encountered during the communication process. Consult the device manuals for specific guidance on configuration and troubleshooting.
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