The Counter Functions - Siemens SIMATIC S5 Manual

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Standard Function Counter

The Counter Functions

The program offers you three different function modes for your applications. You can change these

modes according to your needs via the STEP 5 program. The functions are called:

•

Normal counter function

•

Periodic counter function

•

Cascade function

Two independent 16-bit counters can be used in the NCF and PCF.

A 32-bit counter is available for the CAF.

Normal counter function NCF

The normal counter function is a simple 16-bit up counter. Each counter pulse at the CU input

increments the counter status by 1. When the maximum count has been reached, counting

continues from zero.

No outputs are set in this function; the outputs are generally reset.

Periodic counter function PCF

The periodic counter function is a 16-bit down counter. At the starting point of the periodic counter

function, the counter is set to a specified setpoint. Each counter pulse at the CU input decrements

the count by 1 starting from the setpoint. If the count reaches 0, the assigned output is set and the

count is reset to the setpoint.

A set output can be reset via the RSQ or RSC signals.

Cascade function CAF

The cascade function is a down counter like the periodic counter function but with a data width of 32

bits. It operates in the same way as the periodic counter function.

EWA 4NEB 812 6131-02

NCF

PCF

CAF

The Counter Functions

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