High Speed Position Capture (Latch) - Galil Motion Control DMC-1000 User Manual

High Speed Position Capture (Latch)

Often it is desirable to capture the position precisely for registration applications. The DMC-1000
provides a position latch feature. This feature allows the position of X,Y,Z or W to be captured within
25 microseconds of an external low input signal. The general inputs 1 through 4, and 9 through 12
correspond to each axis.
IN1 X-axis latch
IN2 Y-axis latch
IN3 Z-axis latch
IN4 W-axis latch
Note: To insure a position capture within 25 microseconds, the input signal must be a transition from
high to low.
The DMC-1000 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:
Note: The latch must be re-armed after each latching event.
Instruction
#Latch
JG,5000
BG Y
AL Y
#Wait
JP #Wait,_ALY=1
Result=_RLY
Result=
EN
DMC-1000
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IN 9 E-axis latch
IN10 F-axis latch
IN11 G-axis latch
IN12 H-axis latch
Give the AL XYZW command, or ABCDEFGH for DMC-1080, to arm the
latch for the specified axis or axes.
Test to see if the latch has occurred (Input goes low) by using the _AL X or
Y or Z or W command. Example, V1=_ALX returns the state of the X
latch into V1. V1 is 1 if the latch has not occurred.
After the latch has occurred, read the captured position with the RL XYZW
command or _RL XYZW.
Position Latch Example:
Interpretation
Latch program
Jog Y
Begin motion on Y axis
Arm Latch for Y axis
#Wait label for loop
Jump to #Wait label if latch has not occurred
Set value of variable 'Result' equal to the report position of y axis
Print result
End
Chapter 6 Programming Motion • 81