Siemens simatic s7-400 FM 450-1, Руководство пользователя, Страница: 72 / 130

Modes, settings, parameters and commands
8.12 Initiating a process interrupt
Counter module FM 450-1
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Manual, 02/2014, A5E03648739-02
Opening and closing HW gate
You open and close the hardware gate and set the counter to the load value by applying or
removing the relevant signals at the inputs 1I0 and 1I1 (Counter 1) and/or 2I0 and 2I1
(Counter 2).
Action Initiating event
Opening HW gate (level controlled) Applying signal to input 1I0 (2I0)
Opening HW gate (edge controlled) Applying positive edge to input 1I0 (2I0)
Closing HW gate (level controlled) Removing signal from input 1I0 (2I0)
Closing HW gate (edge controlled) Applying positive edge to input 1I1 (2I1)
In the case of a level-controlled HW gate, a signal at output 1I0 (2I0) is used to reopen the
gate and set the relevant counter to the load value.
If in the case of an edge controlled HW gate a positive edge is again applied to input 1I1
(2I1), the counter resumes counting from the load value irrespective of whether the gate is
closed or still open (retriggering) provided input 1I1 (2I1) is not set.
Behavior at count limits
If the counter reaches the upper or lower count limit and another count pulse arrives, the
counter is set to the other count limit.
Thereafter the gate is closed and the counting process terminated, even if the SW_GATE
parameter is still set or the HW gate is still open. The corresponding status bit is set in the
DB of the FC CNT_CTRL.
Count limit reached Bit in the DB
Upper count limit STS_OFLW is set
Lower count limit STS_UFLW is set
If you want to restart the counter, you must reset the SW_GATE parameter and/or reopen
the HW gate. The counting process is then continued from the load value.
Terminating counting process with the gate stop function
In addition you can terminate the counting process at any time using the gate stop function.
For this purpose you set the GATE_STP input parameter of the FC°CNT_CTRL.