Mitsubishi Electric SW1DNN-WS0ADR-B, Operating Manual

Page: 183 / 322

Chapter 9
180
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 du 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
(3) + (4)
(1) + (2)
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…
Figure 166:
Sequence/timing diagram
for the frequency monitor
function block, release
activation