2/15/2024 4:04 PM | |
Joined: 8/12/2021 Last visit: 8/28/2024 Posts: 323 Rating:
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Hi! I don't understand the doubt. Do you need to apply CRC in modbus communication or do you have an error in the communication? If you have 80C8 in status and it is not responding, I would try checking the connection settings (speed, type...). Also check that the physical connection of the signal is correctly connected to the pins. I have seen a similar problem where the cables had been reversed with the same state (80C8 constant). If you want to add CRC, there are examples in this forum.
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If this Information really helps, you could use the Rate function |
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2/15/2024 5:23 PM | |
Joined: 3/29/2023 Last visit: 8/6/2024 Posts: 4 Rating:
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Hello Swarley92, Thank you for replying. Modbus RTU needs a CRC at the end of the frame. Otherwise, the frame is not complete. Seeing the transmitted frame with the oscilloscope, there is no doubt that the CRC bytes are not transmitted. Also, the slave confirms receiving all the bytes of the frame transmitted, therefore there seems to be no connection problem. I suppose I am getting the 80C8 because the slave discards the received frame, because without CRC it is incomplete and thus invalid and never replies. Is there a setting that I have missed? Am I using the wrong Function Blocks? Is there a bug with TIA v.18? |
7/13/2024 10:01 AM | |
Joined: 8/23/2020 Last visit: 8/12/2024 Posts: 1 Rating:
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I have the same issue! Have you solved it? Thank you |
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