Mitsubishi Electric MELSEC FX Series - Page 384

7 Applied Instructions
7.8 External FX I/O Device
382
FXCPU Structured Programming Manual
(Basic & Applied Instruction)
2) Strobe signal
4. Selection of parameter n
Select by referring to the table below depending on the positive or negative logic of the PLC side, and the
positive or negative logic of the 7-segment display side.
5. Explanation of selection method of parameter n by exemplary cases
When the following 7-segment display is connected, n=1 in the case of 4 digits × 1 set, and n=5 in the case of
4 digits × 2 sets.
1) Transistor output of PLC
- Sync output = negative logic
- Source output = positive logic
2) 7-segment display
- Data input = negative logic
- Strobe signal = positive logic
Logic Negative logic Positive logic
Timing chart
Explanation Data latched at LOW level is held Data latched at HIGH level is held
Logic check
PLC output logic Data input Strobe signal
Parameter n
4 digits × 1 set 4 digits × 2 sets
Negative logic
Negative logic (coinciding)
Negative logic (coinciding) 0 4
Positive logic (not coinciding) 1 5
Positive logic (not coinciding)
Negative logic (coinciding) 2 6
Positive logic (not coinciding) 3 7
Positive logic
Positive logic (coinciding)
Positive logic (coinciding) 0 4
Negative logic (not coinciding) 1 5
Negative logic (not coinciding)
Positive logic (coinciding) 2 6
Negative logic (not coinciding) 3 7
PLC output logic Data input Strobe signal
Parameter n
4 digits × 1 set 4 digits × 2 sets
Negative logic
Negative logic (coinciding)
Negative logic (coinciding) 0 4
Positive logic (not coinciding) 1 5
Positive logic (not coinciding)
Negative logic (coinciding) 2 6
Positive logic (not coinciding) 3 7
H
H
+4 to
H
Strobe display
change
1
8
Latch
None None
+3
d
d
d d
+7
H
Strobe display
change
Latch
None None
HLHL
+4 to
1
8+3
d
d
d d
+7