[PAR_WIG1350]

The PWM from the Spike connects to one of the RELAY channels on the digital sidecar. It doesn't necessarily need to be there for programing, but for operation/debugging, it does. The spike is a relatively simple device that cannot be programed to operate independently. It cannot store and execute machine code, the storage and execution of all code related to the relay modules is handled by the crio and without a data link between the crio and the spike through the digital sidecar, the spike is useless.

I hope this helps.

-Alan

EDIT: I see no reason why you couldn't run a fan off of a spike, but as stated by others, constant operation is, effectively, inconsequential.