Functions; Counting - Siemens Simatic S7-1500 Manual

Technology functions
3.1 High-speed counters
3.1.1

Functions

3.1.1.1

Counting

Counting refers to the detection and adding up of events. The counters acquire and evaluate
encoder signals and pulses. You can specify the count direction using encoder or pulse
signals or through the user program.
You can control counting processes using the digital inputs. You can switch the digital
outputs exactly at defined count values, regardless of the user program.
You can configure the response of the counters using the functionalities described below.
Counting limits
The counting limits define the count value range used. The counting limits are selectable and
can be modified during runtime by the user program.
The highest counting limit that can be set is 2147483647 (2
that can be set is –2147483648 (–2
You can configure the response of the counter at the counting limits:
● Continue or stop counting (automatic gate stop) on violation of a counting limit
● Set count value to start value or to opposite counting limit on violation of a counting limit
Start value
You can configure a start value within the counting limits. The start value can be modified
during runtime by the user program.
Depending on the parameter assignment, the compact CPU can set the current count value
to the start value during synchronization, during the Capture function, on violation of a
counting limit or when the gate is opened.
Gate control
Opening and closing the hardware gate and software gate defines the period of time during
which the counting signals are acquired.
The digital inputs of the digital on-board I/O control the hardware gate. The user program
controls the software gate. You can enable the hardware gate using the parameter
assignment. The software gate (bit in the control interface of the cyclic I/O data) cannot be
disabled.
Capture
You can configure an external reference signal edge that triggers the saving of the current
count value as a Capture value. The following external signals can trigger the Capture
function:
● Rising or falling edge of a digital input
● Both edges of a digital input
● Rising edge of signal N at the encoder input
You can configure whether counting continues from the current count value or from the start
value after the Capture function.
36
).
31
–1). The lowest counting limit
31
CPU 1512C-1 PN (6ES7512-1CK00-0AB0)
Manual, 09/2016, A5E35306440-AB