Siemens SIMATIC ET 200SP Manual page 15

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 the N signal at the encoder input
When using a digital input, you can specify whether counting is to continue from the current
counter value or from the start value after the Capture function. When the rising edge of the
N signal at the encoder input is used, counting is to continue from the current counter value
after the Capture function.
Hardware interrupts
The technology module can trigger a hardware interrupt in the CPU, for example, if a
comparison event occurs, in the event of overflow or underflow, in the event of a zero
crossing of the counter and/or of a change of count direction (direction reversal). You can
specify which events (Page 64) are to trigger a hardware interrupt during operation.
Technology Module TM Count 1x24V (6ES7138-6AA00-0BA0)
Manual, 02/2017, A5E33002339-AB
Product overview
2.2 Functions
15