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Chapter 02 I/O Devices and Sensors
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Chapter 02
Supplement and reinforcement ofInput Devices and Output Actuators
I/O Devices
I/O can be categorized into three areas or types: Binary (Discrete) (Unfortunately to add some confusion they are
also referred to as Digital) This includes all mechanical switches such as: pushbuttons,
selectors, limit (micro), motor starter aux. contacts, relay contacts, etc.
It also includes all solid state sensors such as: photoelectric, inductive and capacitive proximity, etc.
Digital This includes: processed video, charge coupled devices
(CCD) arrays, inductive coil impulse generators, optical code wheels (encoders), etc.
Analog This includes: potentiometers, linear variable differential
transformers (LVDT), video correlation, pressure, temperature, flow, strain, etc.
I/O Details
Mechanically operated switches are mode up of: Pole (sometimes referred to as a wiper) Contact Actuator
Pole orWiper
Pole orWiper
Contact
Contact
Contact
SPST Switch
SPDT Relay
SPSTDB SwitchSingle Pole Single Throw Double Break
Pole orWiper
Contacts
SPDTDB SwitchSingle Pole Double Throw Double Break
Pole orWiper
Contacts
Contacts
Mechanical Switches
Normally Open Normally Closed
Normally Open
Normally Closed
Push Buttons
Selectors
Limit (micro)
Mechanical Switches
Normally Open
Normally Closed
Normally Open
Normally Closed
Normally Open
Normally Closed
Normally Open
Normally Closed
Normally Open
Normally Closed
FLOAT SWITCH PRESSURE SWITCH TEMPERATURE SWITCH
FLOW SWITCH FOOT SWITCH
Relays
Electro-MechanicalNC
NONC
NO
POLE
POLE
NO NC
Switch Bounce
Switch contact bounce
Ø V
+V
+V
PLCInput
Switch contact bounce
Switch Bounce
Ø V
+V
+V
PLCInput
SwitchCloses
Switch comes to
rest
Random‘Bounce’
Sensors
Photoelectric, Inductive and Capacitive
Sensing Theory Primer
Sensors provide the equivalence of eyes, ears, nose and tongue to the microprocessor of a PLC/PAC or computer.
Microprocessor
Opticalsensor
Gassensor
Microphone
Probe
Graphic from: Petruzella, Frank D. (2005). Programmable Logic Controllers (3rd ed.). New York, NY: McGraw-Hill
Review of Basic Solid State Devices
Brief review of: Diodes
Multiple uses within PLC/PAC control circuits DC flyback protection (Inductive surge suppression
for DC inductive loads) Transistors
Commonly used in PLC/PAC DCV output modules Silicon Controlled Rectifiers (SCR) Triac
Commonly used in PLC/PAC ACV output modules
Diode
Current flow in one direction only.
CathodeAnode
Direction ofConventional Current
Forward Bias
A diode will conduct current when the anode is 0.7V more positive than the cathode. When current is flowing the diode is Forward Biased.
+
Direction ofCurrent Flow
+
Reverse Bias
A diode will not conduct current when the anode is not 0.7V more positive than the cathode. When current is not flowing the diode is Reverse Biased.
NO CURRENT FLOW
++
Transistor
Transistors are commonly used as the switching device in PLC/PAC DCV output modules. Just like a diode, a 0.7V bias is required for current flow.
Transistors are available in two polarities, NPN & PNP. NPN Sink PNP Source
NPN PNP
+
+
+
+
+
+
Emitter Emitter
Base Base
Collector Collector
Field Effect Transistors
Field Effect Transistors (FETs) can also be used as switches.
Transistors are current operated devices and FETs are voltage operated devices.
http://www.talkingelectronics.com/projects/MOSFET/MOSFET.html
SCR and Triac
SCRs can be used in ACV output modules but Triacs are more commonly used as the switching device in PLC/PAC ACV output modules
GateCathode
Anode
Gate
Main Terminal 1
Main Terminal 2
SCR and Triac Usage Review
One of the many applications for SCRs and Triacs is for light dimming and simple motor control. They are also used as AC voltage switches.
A Triac in its basic form is nothing more than two SCRs in parallel, back-to-back, with their gates connected together.
SCR Usage – Light Dimmer
Representation of a lamp dimmer circuit using an SCR.
An SCR will only conduct on one half of the sine wave.
ACV
Zero CrossingDetector
Adj. FiringAngle
SCR Usage Review
Waveforms across the lamp at different firing angles. Firing at different angles changes the effective AC
voltage across the lamp (load).
Fired at 30° Fired at 90°
Fired at 135°
Triac Usage – Light Dimmer
Representation of a lamp dimmer circuit using a Triac.
A Triac will conduct on both halves of the sine wave.
ACV
Zero CrossingDetector
Adj. FiringAngle
Triac Usage Review
Waveforms across the lamp at different firing angles. Firing at different angles changes the effective AC
voltage across the lamp (load).
Fired at 30° Fired at 90°
Fired at 135°
AC Effective Voltage (FYI)
SCRs and Triacs change the effective voltage seen by a load.
Power calculations based upon a voltage midway between one peak and zero are not correct because AC voltage generally changes sinusoidal from zero to peak, rather than linearly as in DCV.
The voltage value that gives the correct result is called the Effective Voltage because it has the same effect on a power calculation as does a DC voltage of the same value.
Effective Voltage is equal to the square root of the mean value of the squares of all the instantaneous values of an AC voltage. Because of that, Effective Voltage is also known as the Root Mean Square or RMS Voltage.
AC Voltmeters (FYI)
AC voltmeters read the AC voltage in one of three ways: Average Root Mean Square (RMS) True RMS
Average responding voltmeters simply use a diode to rectify the AC signal being measured and read the equivalent DC voltage. Most VOMs use this method for ACV measurements. (Not very accurate on non-sinusoidal waveforms).
RMS voltage is a function of power and an RMS meter uses electronics to simulate an AC power measurement making the ACV measurement more accurate.
True RMS voltage is also a function of power but also takes into consideration the heating characteristics of the ACV. True RMS voltmeters use a sophisticated µP based calculation that will mimic a bolometer by calculating the area under the curve. This is the most accurate of ACV measurements. This measurement will include any spikes or distortion on the AC signal.
Fairly good source to learn more about measuring AC voltage: http://www.allaboutcircuits.com/vol_2/chpt_1/3.html
Inductive Flyback and Protecting the PLC/PAC
+Vac+Vdc
Photoelectric Sensing
Photoelectric Sensor An electrical device that responds to a change in the intensity of
the light falling upon it. Photocell
A photocell is a device that changes resistance when it is exposed to light. This change in resistance can then be detected to trigger a response. The earliest method of photoelectric sensing used a photocell to sense light change.
Non-modulated The earliest photo sensors consisted of an incandescent light
bulb and a photocell. The gain of the non-modulated sensor is limited to the point at which
the receiver recognizes ambient light. This type of sensor is only powerful if its receiver can be made to
see only the light from its light source (emitter). What are some advantages and disadvantages to this type of
sensor?
Ambient Light Receiver
Ambient light receivers are non-modulated type photoelectric sensors that are still in frequent use.
Applications for such devices could be: Detecting red-hot metal or glass that emit large
amounts of infrared light. As long as these materials emit more light than the
surrounding light level, ambient light receivers can reliably detect these materials.
A sensor mounted under an open frame conveyor that is reading the ambient light in the room. If a box, carton or some other material passes along the
conveyor and over the sensor, it blocks the ambient light from the sensor. This change in light is used to detect the presence of an object on the conveyor.
Light Sources (Emitters)
Light Emitting Diode (LED) A solid state device electrically similar to the diode
except that it emits a small amount of light when it is forward biased.
RED GREEN AMBER
BLUE INFRARED
Light Sensor (Receiver)
Phototransistor A solid state device similar to a transistor except that
the base connection is made using light. These devices are widely used as photoelectric receivers.
Phototransistor
Picture borrowed from the Banner Photoelectric Handbook
Modulated LED Sensors
LEDs can be turned on-and-off at frequencies typically in the kilohertz (KHz) range. This switching on-and-off is referred to as modulating the light.
The receiver can be tuned to this frequency so that it only sees the light signals that pulse at this frequency.
This is what gives the LED sensor its apparent power.
Picture borrowed from the Banner Photoelectric Handbook
Photoelectric Sensing Modes
Opposed Mode Retroreflective Mode Proximity Mode
Diffused mode Divergent mode Convergent Beam mode Fixed-field (sometimes called background
suppression mode) Adjustable-field
Opposed Mode Sensing
Picture borrowed from the Banner Photoelectric Handbook
Receiver
EmitterThe emitter is a light source
Object
Often referred to as “Direct Scanning” or “Break Beam” mode.
In this mode the emitter and receiver are positioned opposite each other so that the light from the emitter is aimed at the receiver.
An object is detected when it interrupts the “effective beam” of light between the two sensing components.
Effective Beam
Photoelectric sensors will sense a change in light when the effective beam is completely blocked.
Effective Beam
Radiation Pattern
Field of View
Emitter Receiver
Shaping the Effective Beam
The effective beam can be shaped by using different sized lenses on the emitter and/or receiver.
Effective Beam is:Cone Shaped
Emitter (or receiver)with large lens
Emitter (or receiver)with small lens
Shaping the Effective Beam
Apertures can also be placed on the lenses to shape the effective beam for sensing small objects that would not normally be large enough to break the effective beam.
Picture borrowed from the Banner Photoelectric Handbook
Retroreflective Mode
This mode is also called “reflex” mode or simply “retro” mode.
The emitter and receiver circuitry of these sensors are in the same package.
The light beam is established between the emitter, a retroreflective target and the receiver.
Just as in opposed mode sensing an object is sensed when it breaks the effective beam.
Retro Target
Object
Picture borrowed from the Banner Photoelectric Handbook
Retroreflective Mode
The range of a retroreflective sensor is defined as the distance from the sensor to its retroreflective target.
The effective beam is usually cone-shaped and connects the periphery of the retro sensor lens to that of the retroreflective target.
A good reflector will return 3,000 times as much light as a piece of white paper. This is one of the reasons that a retroreflective sensor will only recognize the light coming from its emitter.
RetroreflectiveSensor
Radiation patternand field of view
Effective Beam
Retroreflectivetarget
Picture borrowed from the Banner Photoelectric Handbook
Retroreflective Mode – Sensing Shiny Objects
Shiny objects can pass through a retroreflective beam. To cure this problem the sensor and reflector can be mounted to “skew” the light away from the shiny object. Only 10º to 15° is required to be effective.
Boxes with shinyVinyl wrap
Conveyor
Retro target
Skew angle >10°
ReflectedLight
RetroreflectiveSensor
>10°
Flow
Picture borrowed from the Banner Photoelectric Handbook
Retroreflective Mode – Sensing Shiny Objects
It becomes more complicated if the shiny surface is a rounded surface where light can be reflected at unpredictable angles.
Position the sensor so that the light beam strikes the object at both a vertical and horizontal skew angle.
Picture borrowed from the Banner Photoelectric Handbook
Retroreflective target mountedat angle, parallel to sensor lens
Retroreflective sensor mounted at verticaland horizontal angle to the direction of flow
Shiny object with radii
Flow
Tilt up or downand
Rotate right or left
EmittedLight
Retroreflective Mode – Sensing Shiny Objects
Polarizing or anti-glare filters can also be used to reduce the proxing effect on shiny objects.
Emitted Light islinearly polarized
Shiny Object
Retroreflector
Light waves that are reflected by shiny surfaceare in phase with the emitted light and are blocked by the receiver filter
Retroreflected light waves are rotated 90° by thecorner-cube reflector and will pass through the filter to the receiver
Picture borrowed from the Banner Photoelectric Handbook
Proximity Mode Sensing
Proximity mode involves detecting an object that is directly in front of the sensor by detecting the sensors own emitted energy reflecting back from the objects surface.
There are five proxing modes: Diffused Divergent Convergent Fixed field (background suppression) Adjustable field
Diffused Sensing Mode
This is the most commonly used photoelectric sensing mode.
In this mode, the emitted light strikes the surface of the object being sensed at some arbitrary angle.
The light is then diffused from the surface at many angles.
The receiver uses a lens, whereby it can be at some arbitrary angle and still receive a small portion of the diffused light.
Emitted Light
Received Light
Object
Picture borrowed from the Banner Photoelectric Handbook
Divergent Sensing Mode
This is a special short range mode that does not use any lens in an effort to avoid signal loss from shiny objects.
By eliminating the collimating lens, the sensing range is shortened but the sensor is also made less dependent upon the angle of incidence of its light to the shiny surface.
Picture borrowed from the Banner Photoelectric Handbook
Object
Convergent Beam Sense Mode
This mode is very effective for sensing small objects.
They use a lens system to focus the emitted light to an exact point in front of the sensor and also to focus the receiver to this same point producing a small, intense, well-defined sensing area at a fixed distance from the lens.
Depth of Field
Focal Point
ConvergentBeam
Sensor
Picture borrowed from the Banner Photoelectric Handbook
Laser Diode Convergent Sensor
This type of sensor produces an extremely small, concentrated focal point.
The focal point can be in the order of 0.25mm (0.01”) in diameter at a sensing distance of 100mm (4.0”).
The narrow, sharply-defined beam of a laser diode can detect the edge of a semiconductor wafer (775m or 0.03 in.) in a wafer cassette mapping application. (A representation is shown here).
Picture borrowed from the Banner Photoelectric Handbook
Fixed-Field (Background Suppression)
Fixed-field mode has a definite limit to its sensing range. They ignore objects beyond their sensing range regardless of the objects surface reflectivity.
Fixed-field sensors compare the amount of reflected light seen by two differently-aimed receivers, R1 and R2. A target is recognized as long as the amount of light reaching R2 is greater than or equal to the amount of light reaching R1.
A depiction of a fixed-field mode sensor is shown on the next slide.
Fixed-Field (Background Suppression)
Picture borrowed from the Banner Photoelectric Handbook
LensesObject A Object B
Emitter
Receiver
Maximum Sensing Distance
MinimumSensingDistance
FixedSensing
Field
Senses when light received by R2 ≥ the light received by R1
Adjustable Field Mode
Similar to fixed-field, adjustable field sensors can distinguish between objects that are various distances from the sensor.
The receiver produces two currents; I1 and I2. The ratio of the current changes as the received light signal moves along the length of the receiver element.
The sensing cutoff distance is directly related to the ratio of the two currents which are adjustable using either electronic or mechanical adjustments.
Picture borrowed from the Banner Photoelectric Handbook
Sensor Adjustments
Photoelectric sensors need to be properly aligned with the target whether it is a reflector or the object being sensed. The alignment is usually accomplished by mechanically orienting the sensor and/or the target.
Some sensors have “sensitivity” adjustments to adjust the “gain” of the sensor. This adjustment is made such that the sensors output ‘just’ turns on/off when the object to be sensed is within the sensing range.
Excessive gain is a measurement that may be used to predict the reliability of any sensing system. It is the measurement of the sensing energy falling onto the receiver element of a sensing system over and above the minimum amount required to just operate the sensors amplifier.
Sensor Output Operating Modes
Light Operated The sensor output will energize (turn ON)
when the receiver sees light. Dark Operated
The sensor output will energize (turn ON) when the receiver sees an absence of light (darkness).
Sensor Response Time
The response time of a sensor is the maximum amount of time required for the sensor to respond to a change in the input signal (sensing event). It is the time between the leading or trailing edge of a sensing event and the change in the sensors output.
Response time can be calculated and will be different depending upon the type of object being sensed and how the object is moving (axial, radial direction or rotary).
The formulas for calculating the response time can be found in the manufacturers specification sheets or in the manufacturers product catalog.
Training Panel Opposed Mode Sensors
Make adjustments to the photoelectric sensors on the PLC/PAC training panel.
Banner Engineeringhttp://www.bannerengineering.com/en-US/
SM31E & SM31Rhttp://www.bannerengineering.com/en-US/support/partref/25623
Data Sheethttp://info.bannerengineering.com/xpedio/groups/public/documents/literature/03560.pdf
Installation Guidehttp://info.bannerengineering.com/xpedio/groups/public/documents/literature/69943.pdf
Training Panel Fiber Optic Sensors
Use the Internet and look up the specifications and data sheets for the fiber optic sensor.
There are two parts to this sensor, look up both parts Sensor body Power block
Read through the data sheets and attempt making some of the adjustments. (The sensors on the training panel are fairly “beat-up” from use, so don’t get frustrated if the adjustments do not work perfectly).
When you are finished, the sensor should be “ON” when the motor wand is present and “OFF” when it’s not present and the alarm output should be “ON (N/C)” unless an alarm condition exists.
When you are finished, make sure all the sensors have their covers reinstalled and the fiber optic sensor is in “Light Mode” and the opposed mode sensors are in “Dark Mode”.
Inductive Proximity Sensors
Inductive proximity sensors are used to sense metal objects.
The sensing distance is usually specified in millimeters and varies with the size of the sensor. The smaller the sensor, the closer the object to be sensed must get to the sensor. As the sensor gets larger the object sensing distance becomes further.
Operationally they are solid state devices with no moving parts. They consist of a:
coil high-frequency oscillator detector circuit solid state output
Inductive Proximity Sensors
Operationally, a high-frequency field is generated in a coil mounted in the nose of the sensor and directed from the sensing surface of the sensor.
When a metal object enters the high-frequency field, eddy currents are induced into the surface of the target object.
These eddy currents cause a lose of energy in the high-frequency oscillator to occur and the amplitude of the oscillator reduces.
The detector circuit detects the reduction in amplitude of the oscillator and energizes the output circuitry to turn the sensor ON.
Oscillator Detector Output
Target
Inductive Prox. Sensor – Shielded vs. Non-Shielded
Shielded sensor construction includes a metal band that surrounds the ferrite core and coil of the sensor. The band helps to bundle or direct the electro-magnetic field to the front of the sensor.
Non-shielded sensors do not have this metal band and therefore can be sensitive to sensing objects on the sides of the sensor.
Shielded sensors can be safely mounted in metal panels or metal brackets whereas non-shielded sensors require a metal free area around the face of the sensor.
Spacing of adjacent or opposing sensors must be taken into consideration due to the possible interference of the electro-magnetic fields generated. To avoid this problem always leave at least 2-sensor diameters, center-to-center, between adjacent or opposing sensors.
Mounting Inductive Proxs.
When mounting inductive prox. Sensor side-by-side or face-to-face, there needs to be at least two sensor diameters between them so that the magnetic field emanating from the sensors do not interfere with each other causing the possibility of the sensors being ON all the time.
Inductive Prox. Sensor – Sensing range
The normal sensing range of the different sensors is basically a function of the diameter of the sensing area or sensing coil. The shape of the target and the alloy of the metal will also affect the actual operating range.
Correction factors need to be applied to non-ferrous targets and are nominal values.
The table below lists some of these correction factors.
Sensing range multipliers Shielded Non-ShieldedAluminum (foil) approx. 1.00 1.00Stainless steel (alloy dependent) 0.35 to 0.65 0.50 to 0.90Brass 0.40 0.55Aluminum (massive) 0.30 0.55Copper 0.25 0.45
Hysteresis
Hysteresis is the distance between the operating points of an inductive proximity sensor when the target is approaching the face of the sensor and the release point when the target is moving away from the sensor.
As the target approaches the sensor it must always get closer to the sensor to make the sensor turn ON then to make it turn OFF when it is moving away from the sensor.
The following slide demonstrate the hysteresis.
Hysteresis – Axial approach
When the target approaches the sensor in an axial manner the sensor will turn ON when the target reaches the sensors prescribed sensing distance.
When the target is leaving the sensor the target must be moved further away from the sensor then the prescribed sensing distance for the sensor to turn OFF.
TargetAxial approach
Switch point when leaving Sensor turns OFF
Switch pointwhen approaching Sensor turns ON
Hysteresis – Radial approach
When the target approaches the sensor in a radial manner the target must move further in front of the sensor to turn it ON than it has to move away from the sensor to make the sensor turn OFF.
Target
Radial approach
Sensor ON when target approaches
Sensor OFF when target leaves
Capacitive Sensors
Capacitive sensors will sense any object that gets within their sensing range.
They can sense paper, wood, metal, liquid, powders, etc. They are one of the few sensors that are approved by
the Food and Drug Administration (FDA) to come into direct contact with consumable food products.
Oscillator Detector Output
Target
A
C
C
B
B
CB
AFront View
Capacitive Sensors
The active element is formed by two metallic electrodes positioned much like an “opened” capacitor.
Electrodes A and B are placed in a feedback loop of a high frequency oscillator.
When no target is present, the sensors capacitance is low making the oscillator amplitude small.
When a target approaches the face of the sensor, the capacitance increases resulting in an increase in amplitude of the oscillator.
This amplitude increase is detected by the detector and output of the sensor is turned ON or OFF.
Oscillator Detector Output
Target
A
C
C
B
B
CB
AFront View
Capacitive Sensors
Capacitive sensors have a compensation adjustment. Electrode C is the compensation electrode. The adjustment can null the affect of water droplets, humidity, dust,
etc. from affecting the operation of the sensor. In practice the compensation can literally be adjusted to “see
through” objects to another object. As an example, the sensor could be adjusted to read the ink in a felt tip pen after the cap has been placed on the pen. (Actual process at Crayola)
Oscillator Detector Output
Target
A
C
C
B
B
CB
AFront View
Sensor Connections
Sensors come in many connection configurations. Always read the manufacturer wiring specifications before connecting a sensor. Listed are the three most common configurations:
4-wire Sink or Source Some of these sensors can be wired as either sink or source.
Not all 4-wire sensors can be wired in either polarity. Some 4-wire sensors can offer NO and NC operation and/or an alarm output, etc.
3-wire Sink or Source These sensors are specified as either sink or source when
they are purchased. The polarity can not be changed. 2-wire Sink or Source
These sensors can be wired as either sink or source and are becoming very popular because of their simplicity.
Sensor Connections
Sensor connections vary not only between manufacturers, but within the same manufacturer. Always read the manufacturers wiring specifications before connecting a sensor into the circuit.
Wire color coding is sometimes used to identify the sensor connections. The two wires that are most in common across manufacturers are the power connections. Remember…sensors are solid state devices and therefore require power to operate.
Brown wire – +VDC usually 24VDC Blue wire – VDC common
Interpreting Sensor Wiring Diagrams
These wiring diagrams are from the Turck sensor catalog for one particular 3-wire inductive proximity sensor.
Note how the polarity is designated.
Sink sensors supply the VDC common to the load when the switch is closed.
Source sensors supply the +VDC to the load when the switch is closed.
The load in our case would be the PLC input module.
NPN (Sinking)
PNP (Sourcing)
Interpreting Sensor Wiring Diagrams
This is a wiring diagram from the Turck sensor catalog for one particular 2-wire inductive proximity sensor.
Note how the polarity is designated.
Two wire sensors can be wired as sink or source.
Interpreting Sensor Wiring Diagrams
These wiring diagrams are from the Turck sensor catalog for one particular 4-wire inductive proximity sensor.
Note how the polarity is designated.
This sensor has one pole, a normally open (N.O.) and a normally closed (N.C.) contact. (SPDT)
NPN (Sinking)
PNP (Sourcing)
Interpreting Sensor Wiring Diagrams
These wiring diagrams are from the Turck sensor catalog for one particular 4-wire inductive proximity sensor.
Note how the polarity is designated.
This sensor have one pole, a normally open (N.O.) and normally closed (N.C.) contact. (SPDT)
NPN (Sinking)
PNP (Sourcing)
Interpreting Sensor Wiring Diagrams
This wiring diagram is from the Banner Engineering manual for a particular 4-wire sensor.
This sensor is Bipolar, meaning that a sink or source load can be switched depending upon which lead, the white or black, that is connected to the load.
White – Sink connection Black – Source connection
Interpreting Sensor Wiring Diagrams
These diagrams are of a Keyence photo – electric sensor.
This is an example of why the manf. data sheets are required.
I/O MODULES ARE AVAILABLE IN MANY DIFFERENT CONFIGURATIONS
PLC/PAC Module Wiring
I/O Module Wiring
PLC/PAC I/O modules are available in many different wiring configurations: The entire module is either sink or source and
uses one I/O power source. The module is split in two halves where one half
can be sink and the other half can be source or both halves can be sink or source. When used split, two different I/O power sources can be used.
The module is split into more than two halves where each section can be independent from the others or can be combined into one section.
Single Section Module
This is module is a single section module. The polarity (sink or source) of a single section module is determined by the manufacturer and cannot be changed. All I/O must be capable of operating from the same power source.
Split Module – 2 Sections
Group 0 Group 0
Group 1 Group 1
This module is split into 2-sections. The 2-sections are the same polarity, (source), but each section can be powered from a different power source.
Split Module – 4 Sections
Group 0 Group 0
Group 3Group 3
Group 1 Group 1
Group 2 Group 2
This module is split into 4-sections. The 4-sections are the same polarity, (sink), but each section can be powered from a different power source.
Split Module – 2 Sections
This module is split into 2-sections. Each section can be wired as either sink or source and use different power sources. Also, terminals CA and CB can be jumped and the entire module can be wired as either sink or source.
Class Wiring Exercise
Instructor led wiring exercise Equipment
1) Sensor, any polarity 1) Mechanical switch and actuator 1) Lamp assembly or illumination block Wire Various hand tools Disconnect the pre-wired I/O cables.
Recommended