Latch Function - Siemens SIMATIC ET 200S Operating Instructions Manual

1Count5V/500kHz
3.8 Position feedback
3.8.4

Latch Function

Overview
There are two latch functions:
• The Latch and Retrigger function
• The Latch function
The Latch and Retrigger Function
In order to use this function, you must first select it with the "Latch and Retrigger on Positive
Edge" Function DI parameter.
Figure 3-38
This function stores the current internal count of the 1Count5V/500kHz and retriggers
counting when there is a positive edge on the digital input. This means that the current
internal counter status at the time of the positive edge is stored (latch value), and the
1Count5V/500kHz is then loaded again with the load value, from which counting resumes.
The counting mode must be enabled with the SW gate before the function can be executed.
It is started with the first positive edge on the digital input.
The stored count rather than the current count is indicated in the feedback interface. The
STS_DI bit indicates the status of the latch and retrigger signal.
The latch value is preassigned with its RESET state (see corresponding table). It is not
changed when the SW gate is opened.
Direct loading of the counter does not cause the indicated stored count to be changed.
200
Latch and Retrigger with Load Value = 0
Technological Functions
Operating Instructions, 02/2007, A5E00124867-05