Mitsubishi Electric WS0-CPU0 Operating Manual page 183

Figure 166:
Sequence/timing diagram
for the frequency monitor
function block, release
activation
Logic programming – Function blocks

(3) The pulse duration measured is too short: The pulse duration monitoring is
activated (Average value of the pulse duration is not 0) and the time between
the last rising edge and the last falling edge on the Frequency x input is less than
Average value of the pulse duration — Tolerance of the pulse duration. This
monitoring starts with the first rising edge after the transition from the Stop state
to the Run state.

(4) The pulse duration measured is too long: The pulse duration monitoring is
activated (Average value of the pulse duration is not 0) and the time since the
last rising edge on the Frequency x input is greater than Average value of the
pulse duration + Tolerance of the pulse duration. A falling edge has therefore
not been detected in the expected time. This monitoring starts with the first rising
edge after the transition from the Stop state to the Run state.

(5) Input Frequency x is constantly high: The Frequency x input has been high
for longer than Max. period duration. This monitoring starts immediately after
the transition from the Stop state to the Run state.
The Enable x output changes to high if two periods with a valid period duration and
a valid pulse duration are detected on the Frequency x input. If the pulse duration
monitoring is inactive, the pulse duration is always valid for the evaluation.
The Enable x output changes to low if an invalid signal has been measured on the
Freqency x input, i.e. if...

(1) the period duration measured is too short or

(2) the period duration measured is too long or

(3) the pulse duration measured is too short and the pulse duration monitoring is
activated or

(4) the pulse duration measured is too long and the pulse duration monitoring is
activated.
Frequency x
Enable x output
The Frequency x error output becomes high, if...

(1) the period duration measured is too short and the error signal is activated
(Error signal if period duration too short = With) or

(2) the period duration measured is too long or

(3) the pulse duration measured is too short and the pulse duration monitoring is
activated or

(4) the pulse duration measured is too long and the pulse duration monitoring is
activated or

(5) the Frequency x input is constantly high.
The Frequency x constant high output becomes high, if...

(5) the Frequency x input is constantly high.
The Fault present output becomes high, if...
Chapter 9
(3) + (4)
(1) + (2)
180