analog output to analog input short

[Ctl-fool]

Here was an interesting situation I ran into recently:

ALC module (ME Controller) using its 0-10vdc analog output to another ALC (OEM I/O Zone controller) analog input set at 0-5v at In1. Both controllers powered off of same transformer. As soon as controllers are powered up, transformer ckt breaker trips. Tech on site reads ~12vdc (and ac) between input wire and earth ground. If ao wire not hooked to AI, no trip.

I'd shoot for wire mixup as a guess...Ive hooked ao's to ai's before and never seen this (especially if both controllers using same xfr).


Any other guesses?

[xarralu]

Here was an interesting situation I ran into recently:

ALC module (ME Controller) using its 0-10vdc analog output to another ALC (OEM I/O Zone controller) analog input set at 0-5v at In1. Both controllers powered off of same transformer. As soon as controllers are powered up, transformer ckt breaker trips. Tech on site reads ~12vdc (and ac) between input wire and earth ground. If ao wire not hooked to AI, no trip.

I'd shoot for wire mixup as a guess...Ive hooked ao's to ai's before and never seen this (especially if both controllers using same xfr).


Any other guesses?

The gnd on the 24v goes to the chassis of the module. If you don't have the polarity the same on both modules you would have a dead short and possibly some burnt traces on the modules.

[CE-TECH]

I agree with xarralu.
Sounds like the hot from the output is connected to the ground on the input.