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Startup Guide - May 2000 B-63003EN-2/01
3
PMC Addresses
Understanding PMC addressing is very important in grasping how the PMC interfaces with the both
the CNC and the machine tool.
Y address
CNC
Machine
Tool
PMC
F address
G address X address
Figure 3 - 3. Diagram of how addresses are related to each other
If you look at this diagram carefully, it is just simplified version of Figure 3-1. However, it makes
one important point which we have already talked about very clear. The CNC cannot “talk” directly
with the machine tool. They must communicate to each other through the PMC.
If the machine tool generated an alarm such as a
VALVE PRESSURE LOW
signal, it would have to
send a signal to an X address. An address is nothing more than a bit in an 8-bit PMC register. The
PMC would then have to recognize the change in the state of the X bit and output a signal to the CNC
using a G address. Likewise, if the CNC had to respond to this alarm, we would be talking about F
and Y addresses.
Table 3-1 below summarizes the types of PMC addresses:
Table 3 - 1. Description of different kinds of addresses
Symbol Kind of Signal
X Signal from machine to PMC
Y Signal from PMC to machine
F Input signal from CNC to PMC
G Input signal from PMC to CNC
R Internal relay