Siemens SIMATIC ET 200AL System Manual page 430

Counting
4.3 Examples of counting
Behavior DQ - count value between a comparison value and the low counting limit (counting direction
backward)
The following section shows the behavior of the count output with the parameter assignment
"Set output DQ: Between a comparison value and the low counting limit".
The count output is set to "1" if the current values lies between the comparison value and the
low count limit.
You can optionally enable a hardware interrupt through the parameterization. This is
generated with the rising edge of the count output.
The following figure shows an example of the signal state of the count output depending on
the parameterization mentioned above.
Figure 4-14
70
Behavior DQ and hardware interrupt
Digital input/Digital output module DIQ 16x24VDC/0.5A 8xM12 (6ES7143-5AH00-0BA0)
Manual, 09/2017, A5E38688112-AB