DMC-1500 Chapter 6 Programming Motion • 77
High Speed Position Capture (The Latch Function)
Often it is desirable to capture the position precisely for registration applications. The DMC-1500
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 IN 9 E-axis latch
IN2 Y-axis latch IN10 F-axis latch
IN3 Z-axis latch IN11 G-axis latch
IN4 W-axis latch IN12 H-axis latch
Note: To insure a position capture within 25 microseconds, the input signal must be a transition from
high to low.
The DMC-1500 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:
Give the AL XYZW command, or ABCDEFGH for DMC-1580, 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.
Note: The latch must be re-armed after each latching event.
Example - Using Position Capture Function
Instruction Interpretation
#Latch Latch program
JG,5000 Jog Y
BG Y Begin motion on Y axis
AL Y Arm Latch for Y axis
#Wait #Wait label for loop
JP #Wait,_ALY=1 Jump to #Wait label if latch has not occurred
Result=_RLY Set value of variable ‘Result’ equal to the report position of y axis
Result= Print result
EN End
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