High Speed Position Capture (The Latch Function)
Often it is desirable to capture the position precisely for registration applications. The DMC-1600
provides a position latch feature. This feature allows the position of the main or auxiliary
encoders of X,Y,Z or W to be captured within 25 microseconds of an external low input signal.
Faster latch times are available to <1 usec. Please contact Galil. The general inputs 1 through 4
and 9 thru 12 correspond to each axis.
1 through 4:
9 through 12
IN1 X-axis latch
IN9 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-1600 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 XYZW command or ABCDEFGH for DMC-1680, to arm the latch for
the main encoder and ALSXSYSZSW for the auxiliary encoders.
2. 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.
3. 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:
#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
Fast Firmware Operation
The DMC-1600 motion controllers can operate in a mode which allows for very fast servo update
rates. This mode is known as 'fast mode' and allows the following update rates:
DMC-1610 125
usec
DMC-1620 125
usec
DMC-1630 250
usec
DMC-1640 250
usec
DMC-1650 375
usec
114
•
Chapter 6 Programming Motion
DMC-1600
