Hello everyone, I'm currently facing a dilemma with my inability to make a certain function work. Despite dedicating considerable time to experimenting with it, I have yet to achieve success. My objective is to utilize the read_var function block in order to access a holding register through a modbus slave. Unfortunately, I am receiving a '5' in the GEST array. Could the issue potentially lie within my configuration settings? I am utilizing a M580 P582040 PLC. Any assistance on resolving this matter would be greatly valued!
If you are experiencing issues with the GEST pins, it may be because the array you are using is too small. It is recommended to use at least 4 registers for optimal performance. Refer to the Gest Management section in the help file for more information. Additionally, make sure to properly set the 3rd or 4th register of the array as it determines the timeout. Failing to do so may result in malfunctions.
When performing a transaction, utilizing the DTM configuration of the CPU (or NOC) is more beneficial than relying on traditional blocks.
Hi there! It certainly sounds like you're having a bit of a challenge. Based on your description, the '5' you're seeing in the GEST array implies a 'gateway path unavailable' error, which often occurs in situations with incorrect routing. Have you double-checked your configuration settings, especially routing tables? Also, you might want to check if any firewalls or security protocols are blocking your PLC from communicating with the modbus slave. Lastly, make sure your read_var function block is properly initiated; sometimes a minor oversight in parameters can cause unexpected issues. Hope this helps and let us know how you get on!
Hello, it certainly sounds like a tricky situation, but kudos to you for sticking with it! Based on what you shared, my initial thought is that your configuration could indeed be the root cause. A '5' in the GEST array generally indicates a 'Gateway Path Unavailable' error. I'd recommend ensuring your PLC and modbus slave are on the same subnet, and that you have the correct routing established. Also, double check your addressing. Remember that in a Modbus context, you should subtract one from the register number you want to access. I hope this helps!
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Answer: Answer: The read_var function block is used to access holding registers through a Modbus slave in a Schneider M580 PLC.
Answer: Answer: A '5' in the GEST array could indicate an error or issue with the configuration settings when trying to access a holding register through Modbus using the read_var function block.
Answer: Answer: To troubleshoot the issue, you can double-check your configuration settings, ensure proper communication with the Modbus slave device, and verify the data being read from the holding register.
Answer: Answer: Yes, the M580 P582040 PLC is compatible with utilizing the read_var function block for Modbus TCP communication.
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