Operation Result Into Pulse Conversion - Mitsubishi MELSEC System Q Manual

An Introduction to Programming
4.7.12

Operation result into pulse conversion

Instruction
MEP
MEF
The MEP and MEF instructions are used without devices. They generate one output pulse with
the rising respectively falling edge of the input signal i.e. operation result which was valid
before the execution of these instructions. The next pulse is generated with the next rising resp.
falling edge.
Ladder Diagram
The following figure shows the signal sequence for the above example:
Operation result before the
MEP instruction
Operation result after the
MEP instruction
These two instructions are especially suitable for multiple contacts connections. For example,
multiple normally open contacts connected in series would maintain the operation result 1 if
they were all closed. If a relay was set by this operation result, it could not be reset. With a MEP
instruction connected in series with these NO contacts the relay could be reset because the
instruction outputs one pulse only, if the series connection result of all contacts changes from 0
to 1.
MELSEC System Q Beginners Manual
Function
Pulse generation at the rising edge of
operation result
Pulse generation at the falling edge of
operation result
1
X1
0
1
X2
0
1
0
1
M100
0
Relay M100 is only switched on for the duration of a single
program cycle
The Basic Instruction Set
Ladder Diagram IEC Instruction List
MELSEC Instruction List
LD X1
AND X2
MEP
OUT M100
IEC Instruction List
LD X1
AND X2
MEP_M
ST M100
MEP_M
MEF_M
t
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