Siemens SIMATIC ET 200AL, System Manual

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Counting
4.3 Examples of counting
Digital input/Digital output module DIQ 16x24VDC/0.5A 8xM12 (6ES7143-5AH00-0BA0)
Equipment Manual, 08/2021, A5E38688112-AD
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Behavior when a counting limit is exceeded - Stop counting (counting direction forward)
The following section describes the effects of the parameter "Behavior when a counting limit
is exceeded: Stop counting" in the counting direction forward. To control the counter, the bits
of the control byte of the control interface are used, see the configuration method 2xCount,
section Assignment of the control interface (Page 43) and configuration method 4xCount,
section Assignment of the control interface (Page 62).
You have entered the bit string 011 in the control byte of the control interface. This bit string
loads the value defined in the load value (SLOT) as the start value of the counter via the load
request (LD_SLOT).
After the high counting limit is violated, counting is aborted (counting stops) and the
counted value jumps to the low counting limit.
The bit STS_GATE is reset in the feedback interface, the bit EVENT_OFLW is set.
The following figure shows an example of the principle of stopping counting when the high
count limit is exceeded, counting direction forward.
The behavior "Behavior DQ" is set to "Count value between a comparison value and the high
counting limit".
Figure 4-17 Principle: Stop counting (counting direction forward)
You can find additional information on the behavior of the counter at an overflow in the
section Explanations for the feedback interface (Page 46).