IN
*
IOG
IOV
IOG
*
IOV
*
V
R
V
CC
R
I
OFF
I
leak
V
OFF
Two-wire sensor
High-speed Analog Input Unit
Unit that can supply I/O power
to the NX bus
The voltages and currents related to the conditions for PNP type sensors are shown in the figure
below.
I
leak
IOG
IOV
IOG
*
IOV
*
IN
*
V
R
V
CC
R
I
OFF
V
OFF
Two-wire sensor
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
OFF
: OFF voltage at trigger input of the High-speed Analog Input Unit
I
leak
: Sensor leakage current
R: Bleeder resistor
I
OFF
: OFF current at trigger input of the High-speed Analog Input Unit
Precautions on Sensor Inrush Current
An incorrect input may occur due to sensor inrush current if a sensor is turned ON after the High-
speed Analog Input Unit has started up to the point where inputs are possible.
Determine the time required for sensor operation to stabilize after the sensor is turned ON, and
take appropriate measures, such as inserting an ON delay into the user program after turning ON
the sensor.
A programming example is shown below.
The sensor's power supply voltage is used as the input bit to
Sensor_power
.
4 Installation and Wiring
4 - 30
NX-series Analog I/O Units User’s Manual for High-speed Analog Input Units (W592)
