There is no way to directly connect the output of a PID loop (COx) to an analogue output (AOx)
MPM Programming of PID loops
Analog Outputs (AO) do not appear in the drop-down list for the Manipulated Variable parameter of the PID Controller.
If you bind the output to an Analog Value (AV), the AV has no reference parameter to bind to an AO.
Use a Lua Program (PG) to write the AV to the AO.
e.g. if PID controller has AV8 as its Manipulated Variable, the following one line program will write AV8 to AO2 :
ME.AO2 = ME.AV8