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FX3G/FX3U/FX3UC Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
7 Basic Instruction
7.11 MEP, MEF
Caution
1. MEP and MEF instructions may not operate normally if the indexed contact is modified and
changed to pulses by sub-routine programs, the FOR and NEXT instructions, etc.
2. As the MEP and MEF instructions operate using the operation results immediately before them,
use at the list program as the AND instruction.
The MEP and MEF instructions cannot be used at the list program as LD or OR.
3. Caution on writing during RUN
1) Pulse command during rising edge of operation (MEP instruction) results
After writing to the circuit with MEP instructions during RUN, the MEP instruction result turns ON (conductive)
while the operation results up to the MEP instruction are ON.
2) Pulse instruction during falling edge of operation (MEF command) results
After writing to the circuit with MEF instructions during RUN , the MEF instruction result turns OFF (non-
conductive), regardless of the operation results up to the MEF instruction. The operation results of MEF
instruction turns ON (conductive) when the operation results up to the MEF instruction turn OFF.
Error
• There are no calculation errors in the MEP and MEF instructions.
Operation Results up to MEP/MEF Instruction
(while writing is excuted during RUN)
MEP Instruction MEF Instruction
OFF OFF (non-conductive) OFF (non-conductive)
ON ON (conductive) OFF (non-conductive)