Hi All,

Can anyone help me to illustrate the query and response frame structure of DNP3 protocol? Take ModBus protocol for example, i.e.

For Master query command:

Header
Slave Address 06
Function 03
Starting Address Hi 00
Starting Address Lo 6E
No. of Registers Hi 00
No. of Registers Lo 03
Error Check
Trailer

For Slave response:

Header
Slave Address 06
Function 03
Byte Count 06
Data Hi 02
Data Lo 2B
Data Hi 00
Data Lo 00
Data Hi 00
Data Lo 63
Error Check
Trailer

So can anyone list a similar structure for the DNP3 protocol and how many bytes included in each compartment?

Any help will be deeply appreciated.

Kind Regards

Jason

 

I doubt you'll get an answer to this - DNP3 is massively more complex than Modbus. The protocol is sold, not free (okay, is free for paying members). I'm not even sure you can just poll a DNP3 slave & get a response as a single one-off transaction; I think you need to connect and understand context more, so a whole series of transactions must be understood.

You should start with www.dnp.org