Mitsubishi Electric MELSECQ Series User Manual page 53

3 SPECIFICATIONS AND FUNCTIONS
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(1) Input signal ON/OFF status
(a) Input signal ON/OFF status
The input signal ON/OFF status is defied by the external wiring and logic
setting.
This is explained below with the example of near-point dog signal (DOG).
(The other input signals also perform the same operations as the near-point
dog signal (DOG).)
Logic setting*
Negative logic
(Initial value)
Positive logic
(Voltage not applied)
: Set the logic setting using "Switch setting for intelligent function module". For details of the settings, refer to
Section 5.6.
(b) Logic setting and internal circuit
In the QD70, the case where the internal circuit (photocoupler) is OFF in
the negative logic setting is defined as "input signal OFF".
Reversely, the case where the internal circuit (photocoupler) is OFF in the
positive logic setting is defined as "input signal ON".
<Photocoupler ON/OFF status>
When voltage is not applied : Photocoupler OFF
When voltage is applied
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External wiring
(Voltage not applied)
24VDC
(Voltage applied)
24VDC
(Voltage not applied)
24VDC
(Voltage applied)
24VDC
: Photocoupler ON
MELSEC-Q
ON/OFF status of near-point dog
signal (DOG) as seen from QD70
DOG
OFF
COM
DOG
ON
COM
DOG
ON
COM
DOG
OFF
COM
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