Siemens 6ED1050-1AA00-0BE8 Manual De Usuario

LOGO! functions 

 

4.4 Special functions list - SF 

 

LOGO! 

228

 

Manual, 04/2011, A5E03556174-01 

View in parameter assignment mode (example): 

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4.4.23 

Latching relay 

Short description 

Input S sets output Q, input R resets output Q again.  

 

Symbol in LOGO! 

Wiring 

Description 

Input S 

You set output Q with a signal at input S. 

Input R 

You reset output Q with a signal at input R. If S and R 

= 1, the output is reset. 

Parameter 

Retentivity:  

/ = No retentivity 

R = The status is retentive. 

56

4

6
5
3DU

 

Output Q 

Q is set with a signal at input S, and reset with a 

signal at input R. 

Timing diagram 

4

5

6

 

Switching response 

A latching relay represents a simple binary element. The output value depends on the status 

at the inputs and on the previous output status. The following table shows the logic once 

again: 

 

S

n

 

R

n

 

Q 

Comment 

0 

0 

x 

The status is retentive 

0 

1 

0 

Reset 

1 

0 

1 

Set 

1 

1 

0 

Reset (takes priority over Set) 

When retentivity is enabled, the current status of the output signal is retained after a power 

failure.