Yaskawa LEGEND-MC - Manual (Page 289)

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LEGEND-MC User’s Manual
High Speed Position Capture (Latch Function)
Often it is desirable to capture the position precisely for registration applications. The LEGEND-MC
provides a position latch feature. This feature allows position of the main X axis to be captured within 25
microseconds of an external low input signal. General input 1 is the corresponding latch input for the
main encoder.
NOTE: To insure a position capture within 25 microseconds, the input signal must be a transition from
high to low.
The LEGEND-MC 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 X command to arm the latch for the main (LEGEND) encoder.
2. Test to see if the latch has occurred by using the _ALX command. Example, V1=_ALX returns
the state of the X latch to the variable V1. V1 is 1 if the latch has not occurred.
3. After the latch has occurred, read the captured position with the RLX command or _RLX.
NOTE: The latch must be re-armed after each latching event.
To capture the position of the auxiliary encoder, use the command ALSX. The input must be wired to
general input 2. _QL holds the captured position.