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MB_REDSV CPU as server with client Read and Write

Created by: AutoGen_6415 at: 11/20/2014 2:36 AM (21 Replies)

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11/25/2014 12:23 PM	Rate (0)
Dnyanesh Experienced Member Joined: 1/9/2012 Last visit: 8/12/2024 Posts: 40 Rating: (5)	Hi, Did you tried CP443-1 (Modbus TCP server) with Modscan(Modbus TCP Client) on laptop? If this above pair works, then in next step you can connect CP443-1 (Modbus TCP server) to A-B PLC with a Prosoft Modbus TCP module (Modbus TCP Client).

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11/25/2014 7:00 PM	Rate (0)
AutoGen_6415 Posts: 10 Rating: (0)	Getting Modbus Exception from Slave Device (TCP Server)
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11/25/2014 9:46 PM	Rate (0)
Wüstenräuber Gold Expert Joined: 10/3/2008 Last visit: 8/28/2024 Posts: 961 Rating: (124)	Hi, then the client sent a telegram, which the server can't handle. Check the addresses in server. Wüstenräuber

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11/26/2014 6:15 AM	Rate (0)
Dnyanesh Experienced Member Joined: 1/9/2012 Last visit: 8/12/2024 Posts: 40 Rating: (5)	Now check the DB size with following formula "When accessing registers, the last register address which is mapped in the S7 DB can be calculated with the following formula: Last register address in DB = DB-length (in byte) / 2 + start_x - 1 When accessing coils or inputs, the last register address which is mapped in the S7 DB can be calculated with the following formula: Last coil address in DB = DB-length (in byte) * 8 + start_x - 1 " It might work

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11/26/2014 1:06 PM	Rate (0)
AutoGen_6415 Posts: 10 Rating: (0)	Do you mean check the address range to which the client is writing? The server is sending 40001 to 40125. The client is writing 40500 to 40541, 40542 to 40582, 40583, and 40624. Should it write 40500 to 40624. I need more information. I haver never had this much trouble with Modbus before.
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11/26/2014 1:24 PM	Rate (0)
Wüstenräuber Gold Expert Joined: 10/3/2008 Last visit: 8/28/2024 Posts: 961 Rating: (124)	??????? The server can't send any telegram. The client sends reading telegrams and writing telegrams. The server only answer the queries, which are sent from the client. If you want to use the addresses: - 40001 to 40125 - 40500 to 40541 - 40542 to 40582 - 40583 and - 40624 - 40500 to 40624 You must configure the addresses 0 to 623 in the Modbus block. Either you configure these 624 words in 1 data block or you split it in 2 data blocks: 1 data block from 0 to 124 (40001 to 40125) and the other data block from499 to 623 (40500 to 40624). (hint: Each data block needs 2 bytes more at the end of the data block for internal use. See example project.) Important: Only the real addresses (without the identifier 40xxx) are sent via the bus. Wüstenräuber

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11/26/2014 6:45 PM	Rate (0)
AutoGen_6415 Posts: 10 Rating: (0)	This is the latest data from the CPU still with no ability see data written by the client. Attachment Modbus Data.jpg (385 Downloads)
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11/26/2014 8:23 PM	Rate (0)
Wüstenräuber Gold Expert Joined: 10/3/2008 Last visit: 8/28/2024 Posts: 961 Rating: (124)	These data make no sense... START_ADDRESS is "021E", but DATA_TYPE and LENGTH are 0? Save the complete online IDB and post it here. Wüstenräuber

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11/26/2014 9:11 PM	Rate (0)
AutoGen_6415 Posts: 10 Rating: (0)	Here is the IDB1541 Attachment db1541.zip (352 Downloads)
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11/26/2014 9:14 PM	Rate (0)
Wüstenräuber Gold Expert Joined: 10/3/2008 Last visit: 8/28/2024 Posts: 961 Rating: (124)	No, not the offline IDB! The online IDB with the current values.

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