Siemens SIMATIC S7-300 FM 350-1 Manual page 108

Operating Modes, parameters and commands
7.3 Count modes
HW gate control: In HW gate control mode, the count starts or stops instantaneously when
the gate opens or closes:
Figure 7-16
Hardware interrupt
Opening and closing of a HW or SW gate can be used to trigger a hardware interrupt (see
the chapter Triggering hardware interrupts (Page 156).)
Defaults
All gates are open, and the count pulses are counted.
108
Starting and stopping the count using the HW gate (HW_GATE)
FM 350-1 Counter module
Manual, 05/2011, A5E03648639-01