control lab Experiment No 3.pdf

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Experiment No: 3
Name: SENSOR APPLICATIONS (Measuring cycle of a motor by using sensor)
Sensors are sophisticated devices that are frequently used to detect and respond to electrical or optical
signals. Most of sensors convert the physical parameter (for example: temperature, blood pressure,
humidity, speed, etc.) into a signal which can be measured electrically. The sensors can be classified in
accordance to the parameters that needs to be controlled or observed.
Examples are position sensors including potentiometers, optical rotary encoders, and linear
variable differential transformers. Velocity sensors including optical and direct current tachometers.
Proximity sensors including limit switches, optical proximity switches, and Hall-effect switches. Load
sensors including bonded-wire strain gauges, semiconductor force strain gauges, and low-force
sensors. Pressure sensors including Bourdon tubes, bellows, and semiconductor pressure sensors.
Temperature sensors including bimetallic temperature sensors, thermocouples, resistance temperature
detectors, thermistors, and IC temperature sensors. Flow sensors including orifice plates, venturis, pitot
tubes, turbines, and magnetic flowmeters. Liquid-level sensors including discrete and continuous
types. The block diagram below detects the location of sensors in the automatic control system:
Figure 3.1: Block diagram of general control system
Making an application by using the most commonly used sensors in the industry such as
capacitive, inductive and optic sensors that are reflective from reflector; may be with PLC. Aid with
Y-0030-A03 module, connections of sensors and some characteristics features will be examined. With
the help of the DC motor in the module, real applications are modelled and applications can be made.
Purpose: Measuring cycle of a motor by using sensor and PLC. To have knowledge about switching
frequencies of the sensors by trying this application with different sensors
Features of the module;
Proximity sensors detect the presence or absence of objects using electromagnetic fields, light, and
sound. There are many types, each suited to specific applications and environments. In figure 3.2,
sensor application module can be seen. Three types of sensors are available on this module. This
inductive and capacitive sensors are connected to SENSOR1 socket and the optical sensor is connected

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to SENSOR2 socket. All inputs/outputs on the module can be connected to PLC via 2 mm sockets on
"System Inputs" and "System Outputs" tables when required and they can be connected to PLC with
I/O link cable via digital I/O Link connector.
Figure 3.2 Sensor application module.
There are plates that sensors on wings that are connected to DC can detect. At one side of the
wing, there is a reflector that an optic sensor can detect. At the other side of the wing, there is an
aluminium plate. Aluminium plate can be detected by inductive sensor. Capacitive sensor can detect
both wings. Distance of sensors, which are connected to SENSOR1, to the wings can be adjusted by
"sensor connection nuts". When the distance between motor wing and sensor is adjusted, this distance
should not be smaller or bigger than the detecting distance of the sensor.
Figure 3.3: Sensor sockets with electric connection and empty sensor sockets.

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Figure 3.4: Sensor module DC motor section.
Motor Power Supply switch has two positions. When the switch is in Ext position, DC Motor ends are
emptied so that they can allow external connections. When in INT position, motor speed can be
changed with speed potentiometer.
Technical specifications of inductive sensor:
Figure 3.5A: Inductive sensor (connected to SENSOR1 socket).
Figure 3.5B: Inductive sensor (schematic diagram and its work principles).
Detecting distance: 0 … 8mm ( for mild steel)
Switching Frequency: 1000 Hz
Switching output: PNP N.O
Operating Voltage: DC 10V... 30V
Generator Output
amplifier
Metal
Liminal construction
with hysteresis of
frequency
Output
signal

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Figure 3.6: Inductive sensor's detecting distance of various materials
Inductive sensor detecting distance is found by multiplying it with value reduction factor for
various materials. For example; detecting distance is 8 mm for steel and for brass it will be 8
mmx0,25=2mm.
Technical specifications of capacitive sensor:
Due to their ability to detect most types of materials, capacitive sensors must be kept away from non-
target materials to avoid false triggering. For this reason, if the intended target contains a ferrous
material, an inductive sensor is a more reliable option.
Figure 3.7: Capacitive sensor (connected to SENSOR1 socket)
Detecting Distance 0…12 mm (for the material with the lowest density)
Switching Frequency 20 Hz
Switching Output PNP N.O
Operating Voltage DC 10V…30V

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Figure 3.8: Dielectric coefficients of various materials.
Detecting distance of capacitive sensors show differences depending on the dielectric coefficient of
materials. According to the table, the most detected material is water and the less detected material is
teflon.
Technical Features of Optic Sensor Reflective from Reflector:
Figure 3.9: Optic sensor that is reflective from reflector (connected to SENSOR2 socket).
Detecting Distance 80mm… 3.5m (with reflector)
Switching Frequency 400 Hz
Switching Output PNP. N.C Light switching
Operating Voltage DC 10V…30V
Optic sensor reflective from reflector is connected to SENSOR2 socket, when wing with
reflector on the motor is aligned across the sensor, sensor will produce output. When there is an object
between sensor and reflector or reflector is taken from in front of the sensor, sensor output signal is
cut. Output signal of this sensor is connected to I0.1 in the module.
Connection type of the application:

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Figure 3.10: Motor speed measurement with Inductive/Capacitive sensor

control lab Experiment No 3.pdf

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control lab Experiment No 3.pdf