Omron SYSMAC NX series

Precautions When Connecting a Two-wire DC Sensor
When a two-wire sensor is used with the trigger inputs of the High-speed Analog Input Units, check
that the following conditions are met. Failure to meet these conditions may result in operating errors.

Relation between ON Voltage at Trigger Inputs and Sensor Residual Volt-
age
The trigger inputs of the High-speed Analog Input Units can detect sensor output ON only when the
following conditions are satisfied:
V
ON
≤ V
CC
- V
R
The voltages related to the conditions for NPN type sensors are shown in the figure below.
IN
*
IOG
IOV
IOG
*
IOV
*
V
R
V
CC
V
ON
Two-wire sensor
Unit that can supply I/O power
to the NX bus
High-speed Analog Input Unit
The voltages related to the conditions for PNP type sensors are shown in the figure below.
IOG
IOV
IOG
*
IOV
*
IN
*
Two-wire sensor
V
R
V
CC
V
ON
High-speed Analog Input Unit
Unit that can supply I/O power
to the NX bus
V
CC
: Power supply voltage
V
R
: Sensor's output residual voltage
V
ON
: ON voltage at trigger input of the High-speed Analog Input Unit
4 Installation and Wiring
4 - 27
NX-series Analog I/O Units User’s Manual for High-speed Analog Input Units (W592)
4-4 Wiring External Devices
4
4-4-3 Precautions for Wiring