Help with CompactLogix ASCII Module

I have a CompactLogix L30ERM hooked up to a 1769-ASCII module. I'm attempting to use both channels in alternate mode, CH0 is communicating with a torque sensor while CH1 must talk to a stepper controller. I have code written in RSLogix5000 to transmit over CH0 which is fully tested and works to both transmit and receive. The same code was copied with channel numbers changed for use on CH1, but I can't get CH1 to transmit.

I know it isn't completely dead because I can use a PC terminal to send commands to CH1 and I can watch the lights on the module light up when it is receiving, but no dice on transmitting.

I've attached screenshots of my code for CH0 and CH1 for reference.
Any help would be appreciated.

Thanks,
Dave

google 1769-in068_-en-p if you don't have the manual already

are you setting the appropriate CNI,CNO bits?

They should be off when you use CH0, On when you use CH1.

They should be paired up with the CNI,CNO bits in the input file so you know where the data came from.

reset CNI,CNO outputs
send data to ch0
wait for response
check CNI,CNO inputs make sure they are off (ch0)


set CNI,CNO outputs
send data to ch1
wait for response
check CNI,CNO inputs make sure they are on (ch1)

this is just from a quick glance at the manual, i've never used one of these before, but i would bet this is the problem. Also looks like you can only use this mode if you're initiating the send on a specific channel and then waiting for a response on the same channel. Alternate mode is just that, alternating. you cannot use ch0, ch1 simultaneously, so you have to tell the module what port you want to use.