What Should Be Understood Before Using The Ref Instruction - Mitsubishi Electric MELSEC FX3U Programming Manual

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition

13.1.1 What should be understood before using the REF instruction

1. Changing the input filter
The input filter value is determined by the contents of D8020 (initial value: 10 ms).
Use the MOV instruction, etc. to adjust the value in D8020, which represents the input filter value.
Target range: X000 to X017 (In inputs X020 and later, the input filter value is fixed at 10 ms and cannot
be changed.)
(The target range is X000 to X007 in the FX
2. Output response time
After the REF instruction is executed, the output (Y) sets the output signal to ON after the response time
shown below.
Target range: Y000 to highest connected output number
1) Relay output type
The output contact is activated after the response time of the output relay.
- Y000 and higher: Approximately 10 ms
2) Transistor output type
a) FX /FX
3U 3UC
- Y000, Y001 and Y002: 5µs or less (load current = 10 mA or more, 5 to 24V DC)
- Y003 and higher: 0.2ms or less (load current = 100 mA, 24V DC)
b) FX -32MT-LT(-2) PLC
3UC
- Y000, Y001, Y002 and Y003: 5µs or less (load current = 10 mA or more, 5 to 24V DC)
- Y004 and higher: 0.2ms or less (load current = 100 mA, 24V DC)
c) FX PLC (14-point and 24-point type)
3G
- Y000 and Y001: 5µs or less (load current = 10 mA or more, 5 to 24V DC)
- Y002 and higher: 0.2ms or less (load current = 100 mA, 24V DC)
d) FX PLC (40-point and 60-point type)
3G
- Y000, Y001 and Y002: 5µs or less (load current = 10 mA or more, 5 to 24V DC)
- Y003 and higher: 0.2ms or less (load current = 100 mA, 24V DC)
3. When using the REF instruction between FOR and NEXT instructions or between a pointer
(with a lower step number) and CJ instruction (with a higher step number)
Inputs and outputs can be refreshed even when the input information or immediate output is required in the
middle of a routine program during control.
4. When using the input interrupt (I) function
When executing interrupt processing accompanied by I/O operations, I/O refresh can be executed in the
interrupt routine to receive the latest input (X) information and give the immediate output (Y) of the operation
result so that dispersion caused by the operation time is improved.
, FX
3G
→ For details, refer to the respective PLC Hardware Edition manual.
(D, DSS) PLC
13 High Speed Processing – FNC 50 to FNC 59
-16M , FX -16M .)
3U 3UC
13.1 FNC 50 – REF / Refresh
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