Mitsubishi Electronics QD75D Input signal ON/OFF status, About logic setting and internal circuit

3SPECIFICATIONS AND FUNCTIONS

(a)Input signal ON/OFF status

MELSEC-Q

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	External wiring		4		ON/OFF status of near-point dog
3, 4					signal (DOG) as seen from QD75
	(Voltage not applied)
				DOG
		24VDC			OFF
Negative logic				COM
(Initial value)	(Voltage applied)
				DOG	ON
		24VDC
				COM
	(Voltage not applied)
				DOG
		24VDC			ON
Positive logic				COM
	(Voltage applied)
				DOG	OFF
		24VDC
				COM

3: Set the logic setting using " Pr.22 Input signal logic selection". For details of the settings, refer to "Section 5.2.3 Detailed parameters 1" and "Section 13.4 External I/O signal logic switching function".

4: When using the upper limit signal (FLS) or lower limit signal (RLS), always wire it as a "b" (normally closed) contact in the negative logic setting. The signal will turn OFF to stop positioning.

(b) About logic setting and internal circuit

In the QD75, 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 : Photocoupler ON

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