Справочник Пользователя для Mitsubishi Electronics QnUCPU

9

 

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10

9.2.4  

Latch relay (L)

The latch relay (L) is a device for auxiliary relays that can be latched inside the CPU module.

Latch relay data are retained by batteries in the CPU module during power failure.
Operation results (on/off information)

 immediately before the following will be also retained.

 • Powering off and then on the CPU module
 • Resetting the CPU module

The latch relay is turned off by the latch clear operation. (

However, 

the latch relay set in "Latch (2) start/end" in the Device tab of the PLC parameter dialog box 

cannot be turned off even by the remote latch clear function.

There are no restrictions on the number of normally open or closed contacts used in a program, as 
long as the program capacity is not exceeded

.

Scan time is prolonged when the latch relay (L) is used. Reducing the points of latch relay (L) can reduce the prolonging 
scan time. (

 Section 10.1.2)

The output (Y) is used to output sequence program operation results to external devices.

●

If latch is not required, use the internal relay (M). (

●

The latch clear invalid area is set in the Device setting of PLC parameter. (

X0

L0

T0

Y20

X1

L0

L100

X2

L0

L2047

SET

L0

K20

Latch relay (L0) can be set to on only for 
use inside the CPU module, and  not for 
output to the outside.

No restrictions on the quantity used.

M0 is set to on when L0 turns on from off.

The on/off information of L0 is output from the 
output module to the external device.