We usually recommend that the multiplexer be placed close to the CR1000x, but if you must separate them, here are some points to consider:
1. Power: The CR1000x must supply power to drive the relays on the multiplexer, so you must check for a voltage drop caused by the resistance of long cables. See the AM1632 manual for power requirements.
2. Digital Ouput and Pulse: The CR1000x sends a digital signal to reset and clock the relays. The duration and level of this signal can be degraded by long cables. See the AM1632 manual for required voltages.
3. Signal Degradation: The signal from the sensor doesn’t stop at the multiplexer. It continues, unamplified and unfiltered, through the multiplexer all the way to the CR1000x. Long cable lengths are subject to RF noise from the environment and resistance from the cable.