AD-4430B
- 37 -
6.1.4.
Positive Logic And Negative Logic
Negative Logic (A-Contact: Normally open) And Positive Logic (B-Contact:
Normally closed)
The AD-4430B can select the output logic of the output terminals.
The output terminal is conductive in negative logic (A-Contact: Normally open) when the
output signal is "1".
The output circuits of the AD-4430B are an open collector as shown below.
ex. The MINUS output terminal
To light the load LED when the BCD output value is minus, select the negative logic in the
"5.4.5. The BCD Function".
When the power is off, both output terminal logics become non-conductive.
Output logic and behavior (ex. MINUS output terminal)
Output logic
Behavior
Example
Negative logic
(A-contact:
Normally open)
= 1
The MINUS output terminal is
conductive when the BCD output
value is minus.
The load LED is
lit
when the BCD
output value is minus.
Positive logic
(B-contact:
Normally closed)
= 2
The MINUS output terminal is non-
conductive when the BCD output
value is minus.
The load LED is lit when the BCD
output value is plus or zero.
29 MINUS output terminal
Turn on
COM terminal
Inside of AD-4430B
Lights the LED
BCD output value is
minus
