Mitsubishi VFD DeviceNet Question

This is actually a general DeviceNet question. I am a DeviceNet novice.

First, the setup is an SLC 5/05 with a 1747-SDN scanner, RSNetworx for software, 1784-PCD PCMCIA card for the laptop, and RSLogix, naturally.

Most devices I have worked with have a clear I/O map: so many bytes input, so many bytes output; each bit of every byte well-defined and accounted for.

Now, we have two device types which are exceptions: A Mitsubishi VFD (E500 with a FR-E5ND DeviceNet comms card) and an Omron E5EK temperature controller. Lets focus on the Mits. To interface with the controller, the manual speaks of monitering class such-and-such, attribute so-and-so. The manual spells out the object instance, class instance, and attribute of all the parameters. In Networx, I can see these parameters and can see how to change them offline. But I want to online, dynamically monitor and change parameters and I do not know how to map the parameters to the bytes scanned by the scanner.

I am assuming (hah) that RSNetworx can perform the mapping for me, however, I can and will modify the EDS if that is what is necessary to move this along. I just need to bridge that mental gap.

A nudge in the right direction would be most appreciated.

Thanks in advance,

Jim

Usually when I have come across the class, instance, attribute fields they have been for explicit messaging. This can be used to get and set parameters with a controller that supports messaging over DeviceNet. However, you probably won't have to use it.

See the manual page 31 at:

http://www.arrowspeed.com/products/manuals/mitsubishi/VFDs/IB_NA_0600006-B.PDF

The card defaults to output instance 21 input instance 71 which are what you are used to seeing as a well defined I/O Map.

If the defaults are not what you wnat then they can be changed by editing with the class instance editor or messaging.