computer control. computer control basics input – (sensors) processing – (black box) output –...
Post on 21-Dec-2015
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Computer Sensors
• Voltage Producing Sensors
• Variable Resistance Sensors
• Variable Voltage Sensors
Voltage Producing Sensors
• There are two common types used in vehicles and equipment
• Variable Reluctance Sensors
• Hall Effect Sensors
Variable Reluctance Sensors
• These sensors often measure Rotation
• They create their own A/C voltage
• They have many names but work the same
• …Magnetic Pulse Generators
• …Pickup Coils
• …Reluctor Sensors
Variable Reluctance Sensor
• Uses a Reluctor that moves past a coil of wire wrapped around a magnet.
• As the reluctor moves the magnetic flux lines, A/C voltage is induced in the coiled wire.
• It uses 2 wires and create it’s own voltage
• Senses speed and position of rotating objects
Hall Effect Sensors
• Digital sensor
• Uses 3 wires
• positive voltage, ground and signal voltage
• Senses speed and position
• Can sense very slow rotation speeds
Stepper Motor
• Used to control a specific position
• Air Vent
• Cruise Control
• Gauges
• Control Module will “Count” the steps to know what position the motor is in
Understand the CAN-BUS Electrical System
• CAN stands for Controller Area Network
• This allows all the computers (controllers) to “talk” to each other on one set of wires
• BUS refers to a common wire
• Computers talk to each other on a Network where each Controller shares the same voltage signals at the same time
What Language do computers use?
• Digital
• ON - OFF …. High - Low … 1 - 0
• Binary code is either 1 or 0 known as a bit
• 8 bits in a Byte
• How many bits in a Kilo Byte? Mega Byte? Giga Byte? Terra Byte?
What messes up the Communication?
• Open Circuits
• Short Circuits
• EMI
• (Electro Magnetic Interference)
How can you avoid EMI?
• Twist the communication (BUS) wires
• Use a grounded metal shield that surrounds the BUS wires to absorb the energy of moving magnetic flux lines
How can you test for Opens or Shorts in the CAN-BUS?
• Use an Ohm Meter
• Should read total parallel resistance of CAN terminals 1 & 2