Omron CK3M Seres Hardware User Manual page 215

Relation between Input Current to the Digital Input and Sensor
Control Output (Load Current)
I (min) ≤ I
OUT ON
Precautions for Correct Use
The digital input is constant current type input.
For constant current type input, the input current does not increase linearly with the input volt-
age.
If you gradually raise the input voltage, once the input current reaches I
does not increase and remains roughly constant even when the input voltage is raised.
When I is smaller than I
ON
be calculated as follows:
R ≤ (V - V ) / (I
CC R
Power W of bleeder resistor ≥ (V
V : Input voltage of digital input
CC
V : Output residual voltage of sensor
R
I : Input current of digital input
ON
I : Sensor control output (load current)
OUT
Relation between OFF Current of the Digital Input and Sensor Leak-
age Current
The digital input cannot detect sensor output OFF unless the following conditions are satisfied:
I ≥ I
OFF leak
When I is greater than I
leak
Use the following equation to calculate the bleeder resistance constant.
R ≤ (V / I
OFF OFF
Power W of bleeder resistor ≥ (V
Two-wire sensor
V
R
V
V : Power supply voltage
CC
CK3M/CK5M Series Programmable Multi-Axis Controller Hardware User's Manual (O036)
≤ I (max)
OUT
(min), connect a bleeder resistor R. The bleeder resistor constant can
OUT
(min) - I )
OUT ON
2
− V )
CC R
, connect a bleeder resistor R.
OFF
) × V / (I × (V / I
OFF leak OFF
2
− V )
CC R
Digital input
R
CC
V : Output residual voltage of sensor
R
/ R × 4 [allowable margin]
) - V )
OFF OFF
/ R × 4 [allowable margin]
5 Wiring
, the input current
ON
5-37
5