Galil DMC-3425 user manual High Speed Position Capture Latch, Command Summary Homing Operation

Command Summary - Homing Operation

COMMAND	DESCRIPTION
FE ABCD	Find Edge Routine. This routine monitors the Home Input
FI ABCD	Find Index Routine - This routine monitors the Index Input
HM ABCD	Home Routine - This routine combines FE and FI as Described Above
SC ABCD	Stop Code
TS ABCD	Tell Status of Switches and Inputs

Operand Summary - Homing Operation

OPERAND

_HMn

_SCn

_TSn

DESCRIPTION

Contains the value of the state of the Home Input Contains stop code

Contains status of switches and inputs

High Speed Position Capture (Latch)

Often it is desirable to capture the position precisely for registration applications. The DMC-3425 provides a position latch feature. This feature allows the position of the encoders of A or B axis to be captured when the latch input changes state. This function can be setup such that the position is captured when the latch input goes high or low. The inputs on these controllers are TTL. Latch time latency on a high or low going signal is less than 1μsec. Each axis has one general input associated to the axis for position capture:

Input	Function
IN1	A Axis Latch
IN2	B Axis Latch

The DMC-3425 software commands, AL and RL, are used to arm the latch and report the latched position. The steps to use the latch are as follows:

1.Give the AL AB command to arm the latch.

2.Test to see if the latch has occurred (Input goes low) by testing the operand, _ALA or

_ALB. Example, V1=_ALA returns the state of the A latch into V1. V1 is 1 if the latch has not occurred.

3.After the latch has occurred, read the captured position with the command RL AB or RL AB command or monitor the value of the operands _RLA and _RLB.

NOTE: The latch must be re-armed after each latching event.

104 • Chapter 6 Programming Motion DMC-3425