Reference Guide

PMAC Quick Reference Guide

Installing and Configuring PMAC 25

Home Switches

While normally closed-to-ground switches are required for the overtravel limits inputs, the home switches

could be either normally closed or normally open types. The polarity is determined by the home sequence

setup, through the I-Variables

I902, I907, ... I977. However, for the following reasons, the same type of switches used for overtravel

limits are recommended:

• Normally closed switches are proven to have greater electrical noise rejection than normally open

types.

• Using the same type of switches for every input flag simplifies maintenance stock and replacements.

PMACPack and PMAC2 Flag Inputs

The PMAC Pack and PMAC2 interface accessories include a bipolar opto-isolating circuitry (chip PS-

2705-4NEC) for flag and amplifier fault connections:

Flag

Return

Signal

Sinking Signal

(Gnd)

Gnd

Flag

Return

Signal

Sourcing Signal

(+V)

Examples:

Checking the Flag Inputs

In the PEWIN terminal window, define the following M-Variables for the flags of the motors under

consideration:

Flag Type Motor #1 Motor #2 Motor #3 Motor #4

HMFL input status M120->X:$C000,20,1 M220->X:$C004,20,1 M320->X:$C008,20,1 M420->X:$C00C,20,1

-LIM input status M121->X:$C000,21,1 M221->X:$C004,21,1 M321->X:$C008,21,1 M421->X:$C00C,21,1

+LIM input status M122->X:$C000,22,1 M222->X:$C004,22,1 M322->X:$C008,22,1 M422->X:$C00C,22,1

Flag Type Motor #5 Motor #6 Motor #7 Motor #8

HMFL input status M520->X:$C010,20,1 M620->X:$C014,20,1 M720->X:$C018,20,1 M820->X:$C01C,20,1

-LIM input status M521->X:$C010,21,1 M621->X:$C014,21,1 M721->X:$C018,21,1 M821->X:$C01C,21,1

+LIM input status M522->X:$C010,22,1 M622->X:$C014,22,1 M722->X:$C018,22,1 M822->X:$C01C,22,1

Open a Watch Window and press Insert to enter the M-Variable number to watch. Interacting with the

switch or sensor, monitor the change in the corresponding M-Variable. A value of zero indicates that the

flag is closed to ground and therefore the limit is not in fault, the motor will be able to run in that

direction (See Ix25). If the value is 1, the flag is open instead.