Yaskawa SMC–4000 - Manual (Page 304)

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SMC–4000 User Manual
High Speed Position Capture (Latch Function)
Often it is desirable to capture the position precisely for registration applications. The SMC–4000
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
(X–axis) encoder.
*Note To insure a position capture within 25 microseconds, the input signal must be a transition
from high to low.
The SMC–4000 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 (X–axis) 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.