Siemens Simatic ET 200MP Manual page 33

The following figure shows an example of the behavior of the STS_DQ bit between the low
counting limit and comparison value.
Figure 4-12
Counting limits
The counting limits define the range of values of the counted value used. The counting limits
can be set in the parameters and can be changed with the user program during runtime.
Configurable high counting limit: 4294967295 (2
Low counting limit (not settable): 0
You can continue or terminate (automatic gate stop) counting if a counting limit is exceeded,
see the parameter "Behavior when a counting limit is exceeded".
Start value/load value
The start value is specified in the parameter assignment with STEP 7 (TIA Portal). The load
value can be changed by the user program. Both values must be between the low counting
limit and high counting limit.
Comparison values
You specify a comparison value per channel that can control the feedback bit STS_DQ
regardless of the user program. When the current counted value corresponds to the
comparison condition set in the parameters, the feedback bit STS_DQ is set. You can use
the feedback bit STS_DQ to control a digital output of a digital output module.
The comparison values can be set in the parameters and can be changed during runtime via
the user program with parameter data record 0/1.
Gate control
The opening and closing of the software gate (SW-GATE) defines the time window in which
the count signals are acquired. The software gate is controlled by the user program.
Reference
You can find additional information on the counting functionality in the function manual S7-
1500, ET 200MP, ET 200SP counting, measuring and position detection
(http://support.automation.siemens.com/WW/view/en/59709820).
DI 32x24VDC HF digital input module (6ES7521-1BL00-0AB0)
Manual, 09/2016, A5E03485935-AF
Behavior of the STS_DQ bit and hardware interrupt
Parameters/address space
-1).
32
4.2 Address space
33