Counting With Incremental Or Pulse Encoder - Siemens SIMATIC S7-1500 Manual

Product overview
2.2 Functions
2.2.1.2

Counting with incremental or pulse encoder

Counting is the detecting and adding up of events. The counters of the technology module
detect encoder signals and pulses and evaluate them accordingly. The count direction can
be specified using encoder or pulse signals or through the user program.
You can control the counting processes with the digital inputs. In addition, you can read the
signal state of the respective digital input via the feedback interface.
You can specify the counter characteristics using the functions described below.
Counting limits
The counting limits define the counter value range used. The counting limits are configurable
and can be modified during runtime with the user program.
You can configure the behavior of the counter at the counting limits.
Start value
You can configure a start value within the counting limits. The start value can be modified
during runtime with the user program.
Gate control
You can define the time window in which the count signals are acquired with the hardware
gate (HW gate) and software gate (SW gate).
Capture (Latch)
You can configure an external reference signal edge that triggers the saving of the current
counter value as 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
The "Frequency of Capture function" parameter specifies whether the function is executed at
each configured edge or only once after each enable.
Measuring input
If you use Position input for Motion Control (Page 18), you can use the "Measuring input"
technology object to execute a measuring input function with a hardware digital input.
Hardware interrupts
The technology module can trigger a hardware interrupt in the CPU when, for example, a
comparison event, zero crossing and/or a change of count direction (direction reversal)
occurs. You can specify which events during operation are to trigger a hardware interrupt.
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Technology module TM PosInput 2 (6ES7551-1AB00-0AB0)
Manual, 06/2018, A5E03982218-AB