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Lt. Commander

[import] DNP3 Configuration for bit offset

>>Message imported from previous forum - Category:ClearSCADA Software<<
User: jdietz, originally posted: 2019-02-12 23:14:40 Id:367
Hi Everyone,

We're working on transitioning our installed system from FlowStation 110's to SP334's. During our initial setup, the FS110s were configured as MODBUS devices, and register assignments followed that seamlessly.

Now we're setting things up as DNP3, and finding questions faster than answers. As we were working on adding DNP points to the DB, we tried to configure a point with a bit offset to utilize a 16-bit register for multiple digital points. This is something we do regularly with MODBUS. However, when configuring DNP points in CS we found that options for bit offset are non-existent, as is the ability to type a colon or slash after the register to define a certain starting bit.

My question is for anyone who is knowledgeable with DNP3:

Does DNP allow for bit offset, and if so, how do you configure it in CS when working on your point?


Reply User: dmercer, posted: 2019-02-13 03:30:47
That's not something that you can do in DNP3. Digital and analog values are completely separate.
You could manually unpack the binary points from an analog value at the receiver end, but it would be better to remap your points so that binary points are sent as individual DNP3 binary points. This will let you use unsolicited responses properly, which is (IMO) the main benefit of DNP3.

Reply User: jdietz, posted: 2019-02-13 17:21:45
That's what I was afraid of, but also expecting. It's not a huge issue, since we just need to modify our DNP table.

Thank you for helping to clear some of the fog around this for me!