Omron NJ501-1400 User Manual page 161

(3) Relation between current when the Controller is OFF and sensor leakage current:
I
OFF
Connect a bleeder resistor if I
late the bleeder resistance constant.
R  (R
Power W  (V
Two-wire sensor
V :
CC Power voltage
V :
ON Controller ON voltage
V :
OFF
Controller OFF voltage
I :
ON
Controller ON current
I :
OFF Controller OFF current
R :
IN Controller input impedance
(4) Precautions on Sensor Surge Current
An incorrect input may occur if a sensor is turned ON after the Controller has started up to
the point where inputs are possible. Determine the time required for sensor operation to sta-
bilize after the sensor is turned ON and take appropriate measures, such as inserting a
timer delay into the user program after turning ON the sensor.
 Programming Example
In this example, the sensor's power supply voltage is used as the input to SensorVcc. A timer delay
(100 ms for an OMRON Proximity Sensor) is added to the user program to wait for sensor operation
to stabilize. After the timer times out and then the SensorOK input changes to TRUE, a sensor input
to the Sensorln input causes InData to change to TRUE.
Variable
SensorVcc
SensorIn
SensorOK
InData
egPowerDelay
SensorVcc
T#100ms
SensorOK
NJ-series CPU Unit Hardware User's Manual (W500)
 I
leak
leak
 V  R  V
)/(I
IN OFF leak IN
2
 V /R  4 [allowable margin]
)
CC R
V
R
R
V
CC
Data type Initial value
BOOL FALSE
BOOL FALSE
BOOL FALSE
BOOL FALSE
TON ---
egPowerDelay
TON
In Q
PT ET
SensorIn
is greater than I . Use the following equation to calcu-
OFF
OFF )
DC Input Unit
R
IN
V :
Sensor output residual current
R
I :
Sensor control current (load current)
OUT
I :
Sensor leakage current
leak
R:
Bleeder resistance
Address
IOBus://rack#0/slot#0/Ch1_In/Ch1_In00
IOBus://rack#0/slot#0/Ch1_In/Ch1_In01
---
---
---
SensorOK
InData
4 Installation and Wiring
Comment
Sensor power supply volt-
age
Input from sensor
Sensor stable operation
flag
Sensor input data valid flag
Sensor input delay timer
4
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