Rockwell Automation 8520 9/Series CNC Integration Maintenance Manual Documentation Set - Manual (Page 42)

Section 1B
System Overview
1B-16
The system installer uses AMP and PAL to integrate the control to the
machine. The system installer uses PAL to form a ladder logic program
that is continuously executed by the control to control devices such as tool
turrets, limit switches, coolant systems, and lamps.
PAL also controls the I/O process between the control and the machine
tool. Through PAL, system variables, which are assigned to each input or
output terminal of an I/O device, are monitored. PAL uses these variables
to provide system control.
Refer to the 9/Series CNC 9/230, 9/260, and 9/290 PAL Reference Manual,
publication 8520-4.3, for more information.
9/Series I/O devices are linked together by a fiber optic I/O ring. This I/O
ring provides serial communication with the control.
Inputs to the control are first converted to fiber optic signals at the I/O
device. These signals are transmitted through the fiber optic I/O ring to the
control. There they are converted back to electrical signals that can be
monitored and acted on by the PAL program.
Outputs from the control originate from the continuously executing PAL
program which is stored in the control’s memory. They are converted to
fiber optic signals at the control and transmitted through the fiber optic I/O
ring to the appropriate I/O device. There they are converted back to
electrical signals which cause the desired action.
END OF SECTION
1B.11
Programmable Application
Logic (PAL)
1B.12
Fiber Optic I/O Ring