Modal Latching; Latch Request; Canceling A Latch Request; Latch Signals - YASKAWA SVC User Manual

6.4 Modal Latching

6.4.1 Latch Request

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.
Information
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)).
Latch Detection Request
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.
Parameter Type
Setting Parameters
6-12
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.
Bit 4 in OW00
T*
Latch signal
Bit 2 in IW0C
Latch Completed
*
T ≥ t1 + t2 + t3 where T = Latch processing time
Register Address
OW00
Bit 4
OW04
Bits 0 to 3
t1 = Communications cycle
t2 = 2 scans
t3 = Standard SERVOPACK latch processing time (≤ 4 ms)
Name
Latch Detection Request
Latch Detection Signal
Selection
Description
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.
2: Phase-C pulse
3: /EXT1
4: /EXT2
5: /EXT3
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