Thanks for your answer. I am using API mode to talk to the remote modules from the local module. In my application, the PWM output on the remote modules has nothing to do with the A/D input on the remote modules. I want to set a PWM to a particular duty cycle on the various remote modules and leave them alone. Periodically, I want to issue an IS command to read the A/D values (temperature for example) from the various remote modules. I do not want the PWM to change or what appears to briefly go to zero when getting the A/D values.
I'm starting to think the that the PWM duty cycle and frequency control is part of the main loop in the XBee processor and when the processor is busy getting and transmitting the A/D values, the PWM output frequency and/or duty cycle is briefly interrupted. My application cannot tolerate the PWM output changes.
This PWM change occurs on the local module as well when reading the A/D value from the local module.