Siemens simatic s7-400 FM 450-1, User Manual, Page: 66 / 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
8.2 Overview of modes, settings and commands
Which modes are available?
For the FM°450-1 there are the three following modes:
Table 8- 1 Operating modes of FM°450-1
Name Description
Continuous counting
(with or without gate)
Starting from the current counter status the FM°450-1 counts
continuously.
Single counting with SW gate
or with HW gate
When the gate opens, the FM 450-1 counts from the load value to
the count limit.
Periodic counting with SW
gate or with HW gate
When the gate opens, the FM 450-1 counts between the load value
and the count limit.
You can configure the two FM 450-1 counters in different modes.
The default setting is the "Continuous counting" mode.
Choice of count range, behavior of the two digital outputs, pulse duration, evaluation of the
count signals, and the selection of the signal to set the counter all depend on the mode.
Which settings are available?
You can adapt the FM 450-1 to your count job by means of the following five settings:
Table 8- 2 The FM 450-1 settings
Name Description
Count range You select the count limit with the count range.
Behavior of digital outputs Q0
and Q1
You can choose between six possibilities for the behavior of the
outputs on reaching the comparison value.
Pulse duration Pulse duration indicates the time for which the output is to be set.
Triggering hardware
interrupts
When the various selectable events occur, the FM 450-1 can trigger
a hardware interrupt.
Encoders You must specify different settings for the encoder used. These are
described in section "Encoder signals and their evaluation
(Page 93)".