Omron Sysmac NX Series User Manual page 97

Two-wire sensor
V : Power supply voltage
CC
V : Sensor's output residual voltage
R
I : Sensor control output (load current)
OUT
I : Input current at trigger input terminal of the High-speed Analog Input Unit (Input current when
ON
the rated voltage is applied)
R: Bleeder resistor
 Relation between OFF Current at Trigger Inputs and Sensor Leakage Cur-
rent
The trigger inputs of the High-speed Analog Input Units can detect sensor output OFF only when
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
Use the following equation to calculate the rated power of a bleeder resistor.
Rated power W of bleeder resistor ≥ (V
The voltages and currents related to the conditions for NPN type sensors are shown in the figure
below.
NX-series Analog I/O Units User's Manual for High-speed Analog Input Units (W592)
V V
R CC
I I
OUT in
R
, connect a bleeder resistor R.
OFF
) × V /(I × (V /I
OFF leak OFF OFF
CC
IOV
Unit that can supply I/O power
to the NX bus
IOG
IOV
High-speed Analog Input Unit
IN
IOG
) - V )
OFF
2
- V ) /R × 4 [allowable margin]
R
4 Installation and Wiring
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