About Sensors
6-2
KVAL 990-HB Operation / Service Manual
About Sensors
On the 990-HB, sensors provide input to the PLC as part of the automation of the door cutting
process. It is important to keep the sensors cleaned and aligned to keep the door process running
smoothly. There are two classifications of sensors on the 990-HB------Photo Electronic and
Inductive Proximity Sensor.
The
Photo Electronic Detector
uses light as a trigger.
•
Photo Eye Detectors
contain both emitter and receiver. If an object is within the
Photo Eye’s sensing field light from the emitter is reflected from the object back to
the receiver. With
no object
is in front of the Photo Eye a constant 24VDC is sent to
the PLC. If an object is sensed by the Photo Eye, 0VDC is sent to the PLC.
• As a result, any of the photo detectors output equals 0VDC when a door is sensed.
The
Proximity Sensor
detects metallic objects without touching them.
• An inductive proximity sensor consists of a coil and ferrite core arrangement, an
oscillator and detector circuit, and a solid-state output. The ferrite core and oscillator
create a field generating out the front of the sensor. When a metal object enters the
field, a loss in amplitude occurs. The detector circuit recognizes the loss of ampli-
tude and generates 0VDC to send to the PLC. When the metal object leaves the sens-
ing area, the sensor to returns to 24VDC and sends it to the PLC.
• As a result, if a metal object is sensed, the output of the sensor equals 0VDC.
Photo Eye Detector
Emitter and Receiver
in one package
Proximity Detector
Senses metallic
objects
FIGURE 6- 25.
Examples of Sensor
Using Sensors to Trouble Shoot
• Photo Sensors often get dirty. Make sure they are clean. If they are not clean, debris
blocks the signal.
• Check output voltages of the sensors in the
active
mode. The voltage should effec-
tively equal
0 VDC
• Check the output voltages of the sensors in
inactive
mode.The voltage should effec-
tively equal
24 VDC
Summary of Contents for 990-HB
Page 4: ...KVAL 990 HB Operation Manual ...
Page 25: ...Safety Sign Off Sheet 1 17 KVAL 990 HB Operation Service Manual ...
Page 26: ...Safety Sign Off Sheet 1 18 KVAL 990 HB Operation Service Manual ...
Page 66: ...Diagnostic Screen 2 40 KVAL 990 HB Operation Service Manual ...
Page 84: ...Calibration of the Back Section 3 18 KVAL 990 HB Operation Service Manual ...
Page 88: ...System IT Administration 4 4 KVAL 990 HB Operation Service Manual ...