Valve Monitoring - Mitsubishi Electric WS0-CPU0 Operating Manual

Chapter 9
Note
Figure 145:
Sequence/timing diagram
for the External device
monitoring (EDM) function
block
Figure 146:
Function block diagram for
the Valve monitoring
function block, configured
for a directional valve
163
Logic programming – Function blocks
The EDM error and Fault present outputs become Low, if a signal sequence is
detected that sets Output 1 and Output 2 to High.
Alternatively an error can also be reset with the aid of the Error reset input (from
firmware V3.02). The EDM error and Fault present outputs change to low if the Error
reset input changes from low to high and one of the two following conditions is met:
 The Control input is low and the EDM feedback is high.
Or:
 The Control input is high and the EDM feedback is low.
Only if the second of these two possible conditions is met are the outputs Output 1
and Output 2 also high.
If you require a delay of the Output 1 and Output 2 signals, then you have to realize
the output delay with another function block before the EDM function block and not
after it. Otherwise this can result in an EDM error.
Sequence/timing diagram
9.8.8

Valve monitoring

Function block diagram
General description
The Valve monitoring function block allows to control valves and to check on the basis
of their feedback signals whether they have switched as expected.
To this purpose the valves are connected with Output 1a to Output 2b. The feedback
signals are connected to the Feedback 1 and Feedback 2 inputs. The Control 1 and
Control 2 inputs are connected to the logic signal that represents the desired state for
the valve, e.g. the Enable output of a Reset function block. Depending on the valve
type, some of the signals are not used.
Three different valve types are available: Single valves, double valves and directional
valves.