SLC 5/04 with 1791-16AC over RIO

I basically have a SLC 5/04 setup with 4 slots with the last slot having a 1747-SN ser.B. I have 3 other devices on the RIO link and they are already properly configured. Now i want to introduce another device in the RIO link, which is a 1791-16AC AC I/O module.

Here are the thing I've done so I can add a 4th device into the RIO link:
- Configured the G file to look for Rack 3 and to use the full image.
- Moved the terminating resistor from Rack 2 device to the I/O module.
- Set the DIP switch settings as:
- The last rack, processor restart, reset outputs, the correct baud rate, and start at module group 0.

After doing all of that, the COMM light flashes and it tells me that the "Processor in Program Mode". I checked the processor and made sure it's in Run mode and even checked through the RSLogix and it also says that it's not in Program mode. I double checked the wiring of the RIO link, and everything looks good. Even tried swapping the wires just in case.

Anyone have any idea what I'm missing with this picture? I don't know why the remote I/O module would think the processor is in Program mode when I'm not.

Thanks!

-Leo

The controller being in Program Mode is the most common reason for the RIO network LED on the I/O adapter (in this case the 1791 Block) to flash green, but it will also do so if there's something mismatched in the configuration.

The first thing I can think of is the I/O image size. You mentioned that you set up the 1747-SN/B to scan Rack 03 with a Full Rack size (8 Words Input / 8 Words Output).

That 1791-16AC module probably can only operate as a 1/4 Rack of RIO address space. Try reconfiguring the G-file for 1/4 Rack.

If that doesn't do the trick, post the *.RSS file so we can see the G-file configuration and post all the DIP switch positions on the 1791 Block module.

Thanks for the tip! I haven't tried changing the image size down to what it can only occupy, but I figured it would have been okay to specify a full rack any device in the future can just easily tack itself on without the need to reconfigure the G file every time.

Anyway, I'll try setting it for 1/4 tomorrow morning and I'll post my results.

Thanks!

Configured the G to only look for 1/4 rack on Rack 3 and the remote IO module came up!

Thanks for your help, Ken!