Accessory 21S
Introduction 3
Input Source/Sink Control
Jumper E7 controls the configuration of the eight inputs. If it connects pins 1 and 2 (the default setting),
the inputs are biased to +5V for the OFF state, and they must be pulled low for the ON state. If E7
connects pins 2 and 3, the inputs are biased to ground for the OFF state, and must be pulled high for the
ON state. In either case, a high voltage is interpreted as a 0 by the PMAC software, and a low voltage is
interpreted as a 1.
M-Variable Definitions
PMAC’s general purpose I/O can be found as a 24 bit word atY:$FFC2. The suggested M-variables are
defined as follows:
M1->Y:$FFC2,8,1 ;Machine Output 1
M2->Y:$FFC2,9,1 ;Machine Output 2
M3->Y:$FFC2,10,1 ;Machine Output 3
M4->Y:$FFC2,11,1 ;Machine Output 4
M5->Y:$FFC2,12,1 ;Machine Output 5
M6->Y:$FFC2,13,1 ;Machine Output 6
M7->Y:$FFC2,14,1 ;Machine Output 7
M8->Y:$FFC2,15,1 ;Machine Output 8
M9->Y:$FFC2,8,8,U ;Machine Outputs 1-8, treated as byte
M10->Y:$FFC2,0,1 ;Machine Input 1
M11->Y:$FFC2,1,1 ;Machine Input 2
M12->Y:$FFC2,2,1 ;Machine Input 3
M13->Y:$FFC2,3,1 ;Machine Input 4
M14->Y:$FFC2,4,1 ;Machine Input 5
M15->Y:$FFC2,5,1 ;Machine Input 6
M16->Y:$FFC2,6,1 ;Machine Input 7
M17->Y:$FFC2,7,1 ;Machine Input 8
M19->Y:$FFC2,0,8,U ;Machine Inputs 1-8, treated as byte
Accessory 21S Test Setup
Accessory 21 provides an easy interface to PMAC. Simply connect the 34-pin cable from J1 on Acc-21
to J5 of PMAC, define the I/O M-variables, and write a PLC or PMC to respond to the inputs or outputs.
The following PLC can be downloaded to test the Acc-21S.
open plc 1 clear
m9=m19
close
This PLC will have the output byte equal the input byte. As the value of the individual input bits (to
PMAC) are changed, the individual output bits (LEDs) will be enabled.