Omron CK3M Series User Manual

Relation between Input Current to the Digital Input and Sensor
Control Output (Load Current)
I
OUT
(min) ≤ I
ON
≤ I
OUT
(max)
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
ON
, the input current
does not increase and remains roughly constant even when the input voltage is raised.
When I
ON
is smaller than I
OUT
(min), connect a bleeder resistor R. The bleeder resistor constant can
be calculated as follows:
R ≤ (V
CC
- V
R
) / (I
OUT
(min) - I
ON
)
Power W of bleeder resistor ≥ (V
CC
− V
R
)
2
/ R × 4 [allowable margin]
V
CC
: Input voltage of digital input
V
R
: Output residual voltage of sensor
I
ON
: Input current of digital input
I
OUT
: Sensor control output (load current)
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
OFF
≥ I
leak
When I
leak
is greater than I
OFF
, connect a bleeder resistor R.
Use the following equation to calculate the bleeder resistance constant.
R ≤
(V
OFF
/ I
OFF
) × V
OFF
/ (I
leak
× (V
OFF
/ I
OFF
) - V
OFF
)
Power W of bleeder resistor ≥ (V
CC
− V
R
)
2
/ R × 4 [allowable margin]
RV
R
V
C
C
Two-wire sensor Digital input
V
CC
: Power supply voltage V
R
: Output residual voltage of sensor
5 Wiring
5-37
CK3M-series Programmable Multi-Axis Controller User's Manual Hardware (O036)
5-4 Digital I/O Unit Wiring
5
5-4-2 Precautions When Connecting a Two-wire DC Sensor

Omron CK3M Series Specifications

General

Brand	Omron
Model	CK3M Series
Category	Controller
Language	English