11/30/2020 4:33 AM | |
Joined: 1/1/2019 Last visit: 12/19/2022 Posts: 12 Rating: (0) |
Dear Experts, I have an S7 300 programme which is 13 years old. CP 341 is communicating with CAT controller via Modbus RTU and PLC is master. I can check it in HW configuration. FB7 and FB8 are used as protected blocks. They are with DB 70 and DB 50 as instance DB's. My issue is that I would like to be sure which addresses at CAT controller are being written by PLC. I can read values since I can try as 40000 + CAT manual addresses and re-check with display or something else. However on writing side I am not sure. In the attachment you can find screenshots. I see that DB 42 is the source for writing values. In DB 42 I see that slave address is 1, code is 3 and there is an array. There is not the start address as Siemens manual advised. In DB 42 actual values, existing logic seems to be working. At least data is written at the DB 42. In the CP 341 manual I can see input register start address row in a DB. In my programme I can't find a clue on slave start address value... You can estimate that my other issue is that programme is without symbols. Next step will be to migrate to S7 1500. So I have to comprehend the existing situation now before replacement. Any help / idea is appreciated! Thanks in advance. AttachmentForum Modbus RTU Start Register.docx (86 Downloads) |
Last edited by: madelmuhendislik at: 11/30/2020 07:45:54- Engineering Services in Turkey and Region Around |
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