[Al_The_Man]

I assume you are talking Fanuc?
The communication between the CNC and PMC (PLC) is over an inernal bus called the BMI, Basic Machine Interface.
G registers are used to pass info from PMC to CNC such as operator panel commands, and F Registers are used to pass info from CNC to PMC such as M,S,T codes etc.
The PMC operates like any typical PLC as to programming and I/O.
The results of the PLC logic can be monitored in the on screen Ladder display.
Al.

[sinha_nsit]

I assume you are talking Fanuc?
The communication between the CNC and PMC (PLC) is over an inernal bus called the BMI, Basic Machine Interface.
G registers are used to pass info from PMC to CNC such as operator panel commands, and F Registers are used to pass info from CNC to PMC such as M,S,T codes etc.
The PMC operates like any typical PLC as to programming and I/O.
The results of the PLC logic can be monitored in the on screen Ladder display.
Al.

Thanks.
Yes, I am talking with reference to Fanuc, in terms of system variables for interface signals.
A more specific question (I am not sure if I am not talking non-sense):
Can we operate an external relay through PMC, by sending appropriate signal to the PMC through a macro?
For example, let us assume, I want that when the part count is 100, an external siren be automatically sounded. Is it possible?
Additionally, I may want the part count to be displayed on an external display board. Possible?