Siemens SIMATIC ET 200iSP Operating Instructions Manual page 71

Figure 3-9
16-bit down counters (periodic counting function)
The maximum counting range is always 65,535 to 0.
When the counter is started, the actual value is set to the selected setpoint. Each counted
pulse reduced the actual value by 1. Once the actual value reaches 0, the corresponding output
in the PII is turned on and the actual value is set to the selected setpoint. The counter then
counts down from this value.
The positive edge of the
corresponding output in the PII.
A positive edge of the
affect the current count value.
The
assigned output in the PII is reset. Count pulses are processed at the digital input again, but
only at the negative edge. The
when
The setpoint of the counter is set and changed using the POI. The setpoint is adopted on a
positive edge of the
ET 200iSP
Operating Instructions, 11/2017, A5E00247483-07
Principle of operation of the 16-bit up counter
Reset counter control signal resets the selected setpoint and the
Reset output control signal resets the output in the PII. This does not
GATE control signal pauses the counting on a positive edge. At the same time, the
GATE is active.
Reset counter control signal or when the counter has reached zero.
Reset output and Reset counter control signals are also effective
Configuration options
3.16 Counting
71