Convert dnp3 protocol to modbus

[jli63]

Hi all,

I am now having my slave device, which is a SEL 651 proctive relay, talking to computer through DNP3 Ethernet. I have a master model in LabVIEW to see the voltage and frequency transmitted back from the relay.

But right now I want to realize this over Modbus TCP. I have following confusion:

1. I didn't find a Modbus driver, only download a Modbus library from NI website. I am very confused how to replace those main DNP subVIs with Modbus subVIs. Any instrution or hint to guide me would be very appreciated.

2. For the first step, I only 'read' information. How shoud I know which register or coil, i.e. the address of the register and coil, that store the value of voltage and frequency that I want to read from slave SEL 651?

Attached is the code for DNP protocol. Any help is very appreciated!

[Danubio · Accepted solution]

Hi,

You can try to get started to understand how the modbus library is used by checking the examples from the LabVIEW example finder. Specifically:

Modbus library.lvproj

Redundant Modbus Masters.lvproj

Here is also some documentation that I hope it can help:

Modbus Overview
http://home.hit.no/~hansha/documents/industrial_it/resources/resources/modbus/Modbus%20Overview.pdf

Best regards,

Daniel C.