Centroid Community CNC Support Forum

I've been reading through the Macro programming manual trying to get a better understanding of how macro's work and came across this example.
The last line has me stumped. What is 9100?
There is no mention of 9100 in the example until the last line.

Does this call O9101 & O9102?

Yes. It is assumed in the example that the tool-number system variable (#4120) holds either 1 or 2, so the expression [#4120 + 9100] evaluates to either 9101 or 9102.

Ok, Thank you