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Modbus TCP communication problem

Created by: sakal123 at: 5/17/2011 3:02 PM (16 Replies)

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5/18/2011 4:18 PM	Rate (0)
Kaulquappe Posts: 3093 Rating: (323)	Hello Sakel, it is ok as server. If you can't go ahead send me the first twelve byte of the send buffer in the IDB. Regards, Kaulquappe
Kaulquappe Posts: 3093 Rating: (323)
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5/18/2011 4:35 PM	Rate (0)
Kaulquappe Posts: 3093 Rating: (323)	Kaulquappe Hello Sakel, it is ok as server. If you can't go ahead send me the first twelve byte of the send buffer in the IDB. Regards, Kaulquappe No, I need the first twelve byte of the receive buffer. I'm afraid I should take a break....
Kaulquappe Posts: 3093 Rating: (323)
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5/18/2011 4:40 PM	Rate (0)
sakal123 Posts: 29 Rating: (0)	Kaulquappe Hello Sakel, it is ok as server. If you can't go ahead send me the first twelve byte of the send buffer in the IDB. Regards, Kaulquappe In Instance DB102 "DB_MODBUSPN" I found MOD_SERV.PTR_SEND_BUFFER = L#130, MOD_SERV.PTR_RECV1_BUFFER = L#390, MOD_SERV.PTR_RECV2_BUFFER = L#396. In DB6 "DB_MODBUS_PARAM" there is an array internal_send_buffer which values are: B#16#1C, B#16#6E (first two values are rising), B#16#0, B#16#0, B#16#0, B#16#3, B#16#1, B#16#90, B#16#2, B#16#0... all zeros till the end [260]. In DB6 "DB_MODBUS_PARAM" there is an array internal_recv_buffer which values are: B#16#1F, B#16#60 (first two values are rising), B#16#0, B#16#0, B#16#0, B#16#9, B#16#1, B#16#10, B#16#9C, B#16#41 (glitching), B#16#0, B#16#1, B#16#2, B#16#0, B#16#3 (this one is changing between 3 and 4), B#16#0... all zeros till the end [260]. I hope this helps.
sakal123 Posts: 29 Rating: (0)
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5/18/2011 4:51 PM	Rate (0)
Kaulquappe Posts: 3093 Rating: (323)	Hello Sakal, I analyzed the receive buffer, the client accesses the data link layer address 40001. So you have to set START_1 to 40001. Regards, Kaulquappe
Kaulquappe Posts: 3093 Rating: (323)
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5/18/2011 5:22 PM	Rate (0)
sakal123 Posts: 29 Rating: (0)	I got it working. I was following that stupid manual where if using input registers you have to put for index 0, address 30001 and so on. I already tried other numbers before, but then other things were wrong.. I guess the system makes the mapping conversion itself. I'm so glad it finally works :) Thank you very much, I would be at this thing for a long time if it wasn't for you :)
sakal123 Posts: 29 Rating: (0)
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9/25/2015 6:09 PM	Rate (0)
AutoGen_682437 Posts: 13 Rating: (0)	I'm getting the same error, i can send u the code...please contact Kaulquappe Hello Sakal, the difference between data link layer and application layer when adressing is 40001 (with holding registers) and 30001 (with input registers). So I guess you have to set START_1 to 0. The different data types (e.g. holding register and input register) are accessed with distinct function codes. You need to know which function code the client uses if it is not sure which data type is accessed. Regards, Kaulquappe
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9/25/2015 6:25 PM	Rate (0)
Kaulquappe Posts: 3093 Rating: (323)	Hello, I think it is a problem of parameterizing, not of the code. Regards, Kaulquappe
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