Siemens SIMATIC ET 200S Operating Instructions Manual page 142

1Count5V
3.6 Count Modes
Counting is also latched and triggered in isochronous mode with each edge on the digital
input. The counter status that was valid at the time of the last edge before T
the feedback interface.
The Latch Function
In order to use this function, the Function DI parameter must be set to "Latch on Positive
Edge".
Figure 3-10
Counter status and latch value are preset with their RESET states (see RESET states table).
The counting function is started when the SW gate is opened. The 1Count5V begins at the
load value.
The latch value is always the exact counter status at the time of the positive edge on the
digital input DI.
The stored counter status rather than the current counter status is indicated in the feedback
interface. The STS_DI bit indicates the level of the latch signal.
Direct loading of the counter does not cause the indicated stored counter status to be
changed.
In isochronous mode, the counter status that was latched at the time of the last positive edge
before T
When you close the SW gate, the effect is either canceling or interrupting, depending on the
parameter assignment. The digital input DI remains active even when the SW gate is closed.
Expanded Feedback Interface
If the 1Count5V is inserted behind an IM 151 that supports the reading and writing of broader
user data interfaces, the current count value can be read from bytes 8 to 11 of the feedback
interface.
142
Latch with a Load Value of 0
is displayed in the feedback interface.
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Technological Functions
Operating Instructions, 06/2010, A5E00124867-07
is displayed in
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