Ultra3000 DeviceNet Explicit Messaging

Hi All,
I am using a Ultra3000 indexing drive on a an existing PLC5 system. A 1771-SDN scanner module provides the DNet interface to the PLC.

It's working fine in IO messaging mode. I can send commands, and update parameter data.

Problem is, I can't read parameter data back from the drive. UltraWare will only allow Assembly Instance 10, 13 or 15 selections for COS/Cyclic Transmit select. I would need Instance 12 or 14 to read parameter data.

So, I'm trying to use Explcit Messaging to read the parameter Data. The info I have on it is sketchy, just a few paragraphs from the SDN manual. I have a 64 word Block Xfer set up, and it seems close to working. No error messages, but no valid data either.

Can anyone shed some light on this.

Thanks in advance.

Peter

When I'm doing explicit messaging in a controller, I always start by using RSNetworx for DeviceNet to make sure that I have the Class/Instance/Attribute/Service information correct and that I'm getting the data I expect.

Browse to the Ultra 3000i in RSNetworx, then right-click and select "Class Instance Editor". Enter the Service (Get Attribute Single), the Class (0x0F, Parameter), the Instance (the parameter number) and the Attribute (1, the data value).

Post the *.RSP program and the parameters you are trying to read.

Hi Ken,

Thanks for the quick reply.
It's working now!

I had the "Attribute" set to 0, instead of 1.

Cheers,

Peter