Omron CK3M Series, Hardware User Manual

Page: 194 / 288

Failure to meet these conditions may result in operating errors.

Relation between ON voltage of the general digital input / flag input and
sensor residual voltage
V
ON
≤ V
CC
- V
R
V
ON
: ON voltage of general digital input and flag input
V
CC
: Input voltage of general digital input and flag input
V
R
: Output residual voltage of sensor

Relation between input current to the general digital input / flag input and
sensor control output (load current)
I
OUT
(min) ≤ I
ON
≤ I
OUT
(max)
Precautions for Correct Use
The general digital input and flag input are 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 general digital input and flag input
V
R
: Output residual voltage of sensor
I
ON
: Input current of general digital input and flag input
I
OUT
: Sensor control output (load current)

Relation between OFF current of the general digital input / flag input and
sensor leakage current
The general digital input and flag input cannot detect sensor output OFF unless the following condi-
tions 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]
5 Wiring
5-30
CK3M-series Programmable Multi-Axis Controller User's Manual Hardware (O036)