How to program a modbus TCP driver in Labview?

[sophia3]

I’d like to program a Modbus driver on the PC in order to work as a PLC data logger. I downloaded a Modbus Library and implement a Modbus Ethernet(TCP/IP) query. The query communicates with the PLC but can only access to the holding register and read about 100 registers. I’d like to get data from PLC bulk memory which references to  the Modbus File Access (6xxxx) by using the function code 20(read file record), and I am wondering how can I implement this Modbus Function Code 20. Also, I am wondering how to read 3 million registers(which needs to acquire data from PLC continuously) and export the final results to an excel spreadsheet. I guess I need to use buffer? I have no idea how this could be done since I am really a newbie to this field but I work hard on learning it...

[[dk]]

I would recommend looking through this forum post in regards to implementing the Modbus function code 20 in LabVIEW:

http://forums.ni.com/t5/Instrument-Control-GPIB-Serial/Can-I-add-another-Function-Code-to-the-MB-Mod...

I would also recommend that you post this question in the Industrial communications forum as well. It is this forum that any and all Modbus questions should be posted:

http://forums.ni.com/t5/Industrial-Communications/bd-p/260

[sophia3]

Hello Dan,

Thank you very much for the links you provided me. Wish you all the best!

Best Regards,

Sophia