YASKAWA SVC - Modal Latching; Latch Request; Canceling a Latch Request; Latch Signals

6.4 Modal Latching
6.4.1 Latch Request
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6.4 Modal Latching
A modal latch can be used to latch a position independently from the motion command being
executed as long as the motion command being executed is not a motion command with a
latch function, such as EX_POSING, ZRET, LATCH, or EX_FEED.
6.4.1 Latch Request
A latch request is sent when bit 4 (Latch Detection Request) in the OW00 setting param-
eter changes from 0 (OFF) to 1 (ON).
When the latch is completed, bit 2 (Latch Completed) in the IW0C monitor parameter
changes to 1 (Latch completed).
The latch position is reported in the IL18 monitor parameter (Machine Coordinate System
Latch Position (LPOS)).
6.4.2 Canceling a Latch Request
Set bit 4 (Latch Detection Request) in the OW00 setting parameter to 0 (OFF) to cancel
the latch request.
6.4.3 Latch Signals
Phase-C pulse, /EXT1, /EXT2, and /EXT3 signals can be used for latches. Select the latch sig-
nal to use via bits 0 to 3 (Latch Detection Signal Selection) in OW04.
6.4.4 Related Parameters
The parameters that are related to the modal latch function are listed in the following table.
If a motion command with a latch function, such as EX_POSING, ZRET, LATCH, or EX_FEED,
is executed while a modal latch is in use, the motion command takes priority over the modal
latch and is executed first.
Information
*
T*
Bit 4 in OW00
Latch Detection Request
Latch signal
Bit 2 in IW0C
Latch Completed
T ≥ t1 + t2 + t3 where T = Latch processing time
t1 = Communications cycle
t2 = 2 scans
t3 = Standard SERVOPACK latch processing time (≤ 4 ms)
Parameter Type Register Address Name Description
Setting Parameters
OW00
Bit 4
Latch Detection Request
A latch request is made when this
bit changes from 0 to 1.
The latch request is canceled
when this bit changes from 1 to 0.
OW04
Bits 0 to 3
Latch Detection Signal
Selection
2: Phase-C pulse
3: /EXT1
4: /EXT2
5: /EXT3
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