3/3/2017 5:15 PM | |
Posts: 1 Rating:
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Goodmorning, Many thanks for the driver provided. I'm using a s7-300 CPU with CP340 as RS485 for modbus RTU master with step 7. I'm trying to write a Word (2B) in a single register (modbus function code 6) to a slave (inverter, the only slave of the bus). Once the frame is sent, the slave responds with an error code meaning "invalid data amount", and the FB returns "E57 - CRC checksum error". Seems like more data is sent apart the standard RTU frame. Right now i'm not able to send you code or actual values of mbma340 istance DB. I provide the manual of the slave inverter where in page 125 of the PDF there is the message structure in RTU mode. I see in the send buffer in the istance DB more data than the described message. I succeded in another application with the same device as slave, but with s7-1200 with CB1241 RS485 with TIA using the functions MB_MASTER and MB_COMM_LOAD. Many thanks for your help, Regards AttachmentL510 Manual(English)V03 - Copia.pdf (702 Downloads) |
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5/14/2018 3:20 PM | |
Posts: 139 Rating:
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Solved! |
Last edited by: Karls1 at: 5/19/2018 11:13:43 AM |
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4/27/2021 6:51 PM | |
Posts: 1 Rating:
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Hi. I repeated all steps as video for CP341, but i can not to do communication. Modbus Pool write "Bytes Missing Error" Could you help please |
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