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FX3G/FX3U/FX3UC Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
15 External FX I/O Device – FNC 70 to FNC 79
15.5 FNC 74 – SEGL / Seven Segment With Latch
3. Confirming the logic of the seven-segment display unit
1) Data input
2) Strobe signal
4. Setting the parameter "n"
Set a proper value according to the logic (positive or negative) of the PLC and the logic (positive or negative) of the
seven-segment display unit as shown in the table below:
5. Explanation of the parameter "n" setting method according to an actual example
When the following seven-segment display unit is selected, "n" should be "1" when one display unit is connected (4
digits × 1 set) or "5" when two display units are connected (4 digits × 2 sets).
1) Transistor output of PLC
- Sink output = Negative logic
- Source output = Positive logic
2) Seven-segment display unit
- Data input = Negative logic
- Strobe signal = Positive logic
Logic Negative logic Positive logic
Timing chart
Description BCD data at low level BCD data at high level
Check
Logic Negative logic Positive logic
Timing chart
Description Data latched at low level is held. Data latched at high level is held.
Check
PLC output logic Data input Strobe signal
Parameter "n"
4 digits × 1 set 4 digits × 2 sets
Negative logic
Negative logic (match)
Negative logic (match) 0 4
Positive logic (mismatch) 1 5
Positive logic (mismatch)
Negative logic (match) 2 6
Positive logic (mismatch) 3 7
Positive logic
Positive logic (match)
Positive logic (match) 0 4
Negative logic (mismatch) 1 5
Negative logic (mismatch)
Positive logic (match) 2 6
Negative logic (mismatch) 3 7
PLC output logic Data input Strobe signal
Parameter "n"
4 digits × 1 set 4 digits × 2 sets
Negative logic
Negative logic (match)
Negative logic (match) 0 4
Positive logic (mismatch) 1 5
Positive logic (mismatch)
Negative logic (match) 2 6
Positive logic (mismatch) 3 7
+1
Seven-segment
display
2
1
4
8
HH
H
+2
+3
D
D
D
D
Seven-segment
display
2
1
4
8
H
H
HH
H
L
L
L
+1
+2
+3
D
D
D
D
H
H
...
H
Change in
strobe display
1
8
Latch
Nothing Nothing
+4 to +7
+3
...
D
D
D
D
H
Change in
strobe display
1
8
Latch
Nothing Nothing
HLHL
...
+4 to +7
+3
...
D
D
D
D