Siemens simatic s7-400 FM 450-1, User Manual, Page: 11 / 130

Product Overview
1.5 The FM 450-1 software
Counter module FM 450-1
Manual, 02/2014, A5E03648739-02
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Diagnostic interrupt
When the following events occur, the FM 450-1 can trigger a diagnostic interrupt:
● External auxiliary voltage faulty
● Encoder 5.2 VDC supply faulty
● Module not assigned parameters or errors in parameter assignment
● Watchdog timeout
● RAM defective
● Hardware interrupt lost
● Fault in signal A, B, or N of the 5 V encoder
Pulse duration
You can determine a pulse duration for the digital outputs of the FM 450-1. The pulse
duration is used to specify how long the corresponding digital output is to be set. You can
specify a value between 0 and 500 ms for the pulse duration. This value applies to both
outputs. By prescribing a pulse duration you can adapt the FM 450-1 to existing actors.
Which signals can the FM 450-1 count?
The FM 450-1 can count signals that are generated by the following encoders:
● Incremental 5-V encoders
● Incremental 24-V encoders
● 24-V pulse encoders with direction level
● 24-V initiators without direction level
e.g., light barrier or BERO
Input filter
For the purpose of suppressing interference, you can assign input filters (RC elements) with
a uniform filter time for the 24 V inputs A*, B*, and N* and for the digital inputs. The following
two input filters are available:
Table 1- 1 Input filter
Characteristics Input filter 1
(default) Input filter 2
Typical input delay 1 μs 15 μs
Maximum count frequency 200 kHz 20 kHz
Minimum pulse width of the count signals 2.5 μs 25 μs