5130, 5130B and 5230 Excavators, 784B, 785B, 785C, 789B, 789C, 793B and 793C Off-Highway Truck/Tractors and 992G, 994 and 994D Wheel Loaders Vital Information Management System (VIMS) Caterpillar


Glossary of Terms

Usage:

793B 1HL
Abuse - A machine or a engine is operated in a way that could possibly damage the machine.

Abnormal - The condition of a machine system is not normal or a signal of a machine system is not within expected limits. An abnormal condition or a abnormal signal means that a problem exists. The operator should be notified with a warning when an abnormal condition exists.

Absolute Pressure (PSI or kPa) - The pressure is measured with respect to the atmospheric pressure. Atmospheric pressure is approximately 101 kPa (14.7 psi). See Gauge Pressure.

Active - This pertains to the status of a fault or to the status of a service code. When the fault is active, the fault is currently present.

Active Fault - This is a type of diagnostic maintenance event. The maintenance event identifies a specific failure in an electronic control system. See Event and Fault.

Active Sensor - The sensor is externally powered. The sensor must have at least three lead wires. See Passive Sensor

Advanced Diesel Engine Management (ADEM)k - This electronic engine control is used by Caterpillar gas engines and diesel engines.

Air Gap - This is the distance between a gear tooth and the tip of a magnetic pickup. This is also the distance between the rotor and the stator of an alternator or a generator.

Alert Indicator - This is the red indicator lamp that is located in the display area. The lamp flashes when a problem exists. The associated warning indicator pictograph or the VIMS message center module identify the abnormal condition of a machine system. This is part of the operator warning system. The indicator typically means that the machine needs attention. However, the machine is able to continue operation. The abnormal condition must be checked in accordance with the machine's Operation and Maintenance Manual.

Alternator - This is a electromechanical device that converts rotating mechanical energy into electrical energy in the form of alternating current.

Alternating Current (AC) - This is a flow of current that flows in both directions. This process repeats continuously. The number of such cycles per second is called the frequency.

American Wire Gauge (AWG) - This is a measure of the diameter of electrical wire. As the AWG number becomes smaller, the wire diameter becomes larger. Thicker wires handle more current.

Ampere "I" - The standard unit of measure for current flow in a circuit.

Analog Display - A type of readout that shows information with a needle that sweeps across a dial face. See Digital Display.

Analog Sensor Power Supply - This is a power source in a Caterpillar electronic control system, that powers analog sensors. The power source is usually rated at 5 DCV.

Analog Signal - This is a signal voltage from an analog sensor. The signal varies smoothly over time. The variations are caused by the changing conditions that are sensed.

Analog Sensor - This is a device that generates a DC signal between +0.2 and 4.8 Volts. The sensor signal is proportional to the mechanical system that is being monitored. Analog sensors are most often used with electronic engine controls. See Digital Sensor.

ARC - See Automatic Retarder Control.

Atmospheric Pressure Sensor - This is a device that generates a signal that is proportional to atmospheric pressure. This is usually an analog sensor.

Automatic Braking System (ABS) - An electronic control system for controlling brakes in slippery underfoot conditions.

Automatic Engine Speed Control (AESC) - This is used by excavators in order to reduce the engine speed to about 1300 rpm. This is used in order to save fuel during periods when the hydraulic system is not being used.

Automatic Electronic Traction Aid (AETA) - This is an electronic control system for Off Highway Trucks. The system reduces the wheel slip that is caused by poor underfoot conditions.

Automatic Retarder Control (ARC) - This is an electronic control that monitors the engine speed. The control automatically applies the retarder on downhill slopes. This is done in order to reduce the possibility of an engine overspeed.

Base Sample Rate - This is the fastest available sample rate that is available for configuring a snapshot recorder or other stored data. See Sample Rate.

Battery - This is a device that stores electrical energy. The typical battery that is used in Caterpillar electrical systems is the 12 Volt lead acid. The batteries are used to start the engine. Each battery is made up of six cells.

+Battery - This is the voltage that is found on all wiring harnesses that connect to the positive battery post of the electrical system. The +Battery voltage is also known as the system voltage.

-Battery - This term is sometimes used to designate the chassis ground or the negative side of the battery. See Ground.

Battery Backed Up RAM (BBR or BBRam) - This is the Random Access Memory (RAM) that is contained in an electronic control that is protected by an internal battery. The data that is held in the Random Access Memory will be lost if the external power is disconnected without the internal battery. See Volatile Memory.

Breakout T-Harness - This is a test harness that connects into a machine harness or a engine harness. The breakout T-harness connector cable allows the normal operation of the system. The cable also provides a connector that allows the hookup of test equipment.

Broadcast - This is a process that transfers data from a mobile unit (machine or vehicle) to a stationary location. This is usually a wireless transfer. See Telemetry. This term also describes the Data Link communication between electronic controls. One control automatically sends a message to other controls on the Data Link.

Bypass Circuit - This is a circuit that temporarily replaces the existing circuit during a test.

Calibration - This is the adjustment of an electrical signal that is related to a mechanical linkage or a component. For example, the small differences that occur between the output of the atmospheric pressure sensor and the boost pressure sensor can be corrected by calibration.

CAT Data Link (CDL) - The CAT data link is an electrical connection for communication with onboard devices that use the Data Link (ECM, CMS, VIMS, electronic power train, electronic dashboards and service tools such as Caterpillar Electronic Technician). The CAT data link is also the medium that is used for programming with Caterpillar service tools and for troubleshooting with Caterpillar service tools.

Category 1 Warning - This is a red alert indicator that flashes in order to warn the operator that a Category 1 Warning condition exists. The indicator also indicates the failed machine system. The Category 1 condition needs attention by the end of the shift.

Category 2 Warning - This is a red alert indicator that flashes in order to warn the operator that a Category 2 condition exists. The indicator also indicates the failed machine system. The action lamp also flashes in order to indicate Category 2 warning. The presence of this category usually indicates that the operator must alter the operation of the machine or that the service technician must perform maintenance. This warning most often relates to a system temperature that is too high.

Category 2S Warning - This is a special version of the standard Category 2 warning that includes a CONTINUOUS action alarm. The action alarm is used in order to get the operator's attention in situations that may be normally overlooked.

Category 3 Warning - This is a red alert indicator that flashes in order to warn the operator that a Category 3 condition exists. The indicator also indicates the failed machine system. The action lamp also flashes in order to indicate a Category 3 warning. The action alarm sounds ON and OFF. This warns the operator to safely shut down the machine. There is an exception to this warning. When the parking brake is turned ON and the transmission is in gear.

Caterpillar Electronic Technician (ET) - This is a Windows based program, that is used to service Caterpillar products. The software operates on a service tool (personal computer).

CDL - See the CAT Data Link.

CD-ROM - See Compact Disk Read Only Memory.

CE Connector - This is a multipin connector with a hard shell. This connector is made by Deutsch for use in the Caterpillar Environment (CE). The contacts of the connector are serviceable. The contacts are interchangeable with the contacts of the VE Connector. The locking ring is a quick disconnect.

Central Processing Unit (CPU) - This is the hardware that makes up the part of a computer system that actually processes data.

Channel - This describes an input to an electronic control. This may also be a frequency that is used for a voice transmission and/or the transmission of data.

CID - See Component Identifier.

Circuit - This is a path for the continuous flow of electrical current. The current will flow from a power source through various conductors and back to the source.

Clear - This is the removal of diagnostic information that is stored in the memory of an electronic control. Before clearing a failure, the failure must be on hold and the failure must not be present. This has the same meaning as Reset. Clear is the preferred term. See Reset.

Communication Adapter - This is a device that allows the service tool to communicate with an electronic control over the CAT Data Link and the ATA Data Link. The communication adapter converts the CAT Data Link Communications and the ATA Data Link communications to RS-232and vice versa.

Compact Disc-Read Only Memory (CD-ROM) - This is Read Only Memory. The data is stored on a compact disk. This memory is used by the Caterpillar Service Information System and the Caterpillar Electronic Technician.

Component Identifier (CID) - This is a diagnostic code that identifies a component or a system that is faulty. This is a four digit diagnostic code. The code is sometimes preceded by a C or CID.

Conductor - This is any material that can carry an electrical current. An example of a conductor would be a wire in a wiring harness.

Configuration Software - This is the information that is provided for use by the onboard system. This information contains specific characteristics of the machine.

Connector - This is a device that is usually constructed of two pieces that mate. A connector provides a way to easily disconnect circuits or separate circuits. Connectors are also used for hydraulic circuits or pneumatic circuits.

Connector Contact - This is a component of a harness connector that actually makes the electrical connection. Connector contacts can be either pins (male) or sockets (female).

Continuity - This is one property of a complete electrical circuit. The correct resistance depends on the circuit that is being tested.

Control - See Electronic Control.

Coolant Temperature Sensor (CTS) - This is a device that generates a signal that is proportional to the engine coolant temperature.

Cumulatives - This term is sometimes referred to as "Cums". "Cums" relate to data that is stored on board the machine. This information consists of totals such as total engine revolutions, total distance travelled or total fuel burned. The Cumulatives can be used to schedule maintenance prior to a expected failure.

Current - This is the flow of electrons in a circuit. Current is measured in Amperes. The standard symbol for current is the letter "I".

Data Event - This is an abnormal machine or engine condition. These conditions can affect the machine or the engine life.

Data Link - This is a circuit that is used for digital communications. The communications occur between electronic controls or the communications occur between electronic controls and a service tool.

Deadband - This is a range of input signal values that are specified so the output of a control will remain constant.

Decibel (dB) - This is approximately the smallest change in sound volume that can be detected by the human ear.

Default - This is the initial value of a parameter prior to programming by the customer. This is also the value of the parameter after the system has been reset.

Derate - This is the operation of the system at a setting that is below a desired limit.

Detected Fault - See System Event and Diagnostic Code.

Diagnostic - This is a process that takes place within an electronic control. The control senses the abnormal machine information. The control displays the abnormal machine information. The control stores the abnormal machine information. This stored information can aid the service technician.

Diagnostic Clock - This is a clock within an electronic control. The clock increments time only when +Battery is connected to the control by turning the key start switch to the ON position. This time is known as diagnostic hours. This time will always be MORE than engine running time or the true Service Meter Hours. See Diagnostic Hours.

Diagnostic Code - This is a code that is generated from a diagnostic type of maintenance event. This code relates to an abnormal condition in an electrical system that has been detected by an electronic control. See Service Code.

Diagnostic Connector - This is a service connector. This is normally a CE connector that contains 20 sockets. The connector brings the test points that are required in testing the starting and charging circuits to a common point. This permits testing with either a multimeter or dedicated 6V-2150 Starting/Charging Analyzer. A Deutsch connector with 12 contacts is used on products that use only one starter. On products that use twin starter applications, a second Deutsch connector with 8 contacts is necessary.

Diagnostic Event - This is a type of maintenance event. This event is displayed when an electronic control detects an abnormal condition in the electrical system. Sometimes abnormal conditions in the mechanical system can be detected through the electrical system.

Diagnostic Event Code - See Event and Diagnostic Code.

Diagnostic Fault Code - See Diagnostic Code.

Digital Display - This is a type of readout that shows information in the digital format (numbers and letters). See Analog Display.

Digital Power Supply - This is a power source that powers digital sensors in a control system. This is usually 8 Volts DC power supply.

Digital Sensor - This is a device that generates an output signal that oscillates between two different voltage levels. Either the frequency of the signal or the duty cycle of the signal changes in order to carry the sensed information. The digital sensor can be powered by voltages that are between 8 and 28 DCV. The voltage that is used depends on the sensor. See Analog Sensor.

Digital Voltmeter (DVM) - This is a voltmeter with a digital display.

Direct Current (DC) - This is flow of electrons (current) in a closed circuit, that moves in only one direction through a conductor.

Disconnect Switch - This is a battery disconnect switch that is connected between the battery's negative terminal and frame ground (chassis). This switch is most often a keyswitch. This switch may be controlled electronically on some machines. The switch is used in order to disconnect the electrical system from the machine for service. The switch is used when a machine is placed in storage for periods longer than one month.

Display - A gauge, indicator and digital readout. The display is used to view the status of a machine.

Disk Operating System (DOS) - This is the software that contains the internal operating instructions for the computer. This software also allows the manual input of commands by the computer operator. All computer systems have some type of operating system in order to function.

Download - The process of moving or transferring stored information from an electronic control to an off-board system such as a service tool. See Upload.

Driver - This is the electrical circuit that powers an output of an electronic control. The driver turns on lamps, solenoids, relays, etc.

Duty Cycle (DC) - This is the ratio of ON time to the total time of a digital signal. An example of duty cycle of 50 percent is a signal that is ON for one second and Off for one second. See Pulse Width Modulation.

Electrically Erasable Programmable Read Only Memory (EEPROM) - This is a version of EPROM that can be programmed. Sometimes, an electronic control can WRITE to this memory. See Erasable Programmable Read Only Memory.

Electromagnet - This is a temporary magnet that consists of a coil of wire that is wrapped around an iron core. The assembly becomes a magnet only when a magnetic field is produced by an electric current passing through the coil. Relays work on this principle.

Electromagnetic Interference (EMI) - This is the response of an electronic component or system to electromagnetic radiation. The interference usually causes a reduction of performance.

Electronic Control Analyzer Programmer (ECAP) - This is computer based service tool that is dedicated to programming and diagnosing a variety of electronic controls. The service tool uses the Communications Adapter in order to communicate through the CAT Data Link or the ATA Data Links (SAE J1708/1587).

Electronic Control Module (ECM) - This is an electronic control. The control monitors machine systems. The control also outputs commands to drive components. The term was formerly used to specifically describe an electronic engine control.

Electromagnetic Pickup - This is a permanent magnet that is wrapped with many turns of small wire that becomes a pickup coil. The pickup coil will generate an electrical pulse whenever a gear tooth passes the tip of the magnet. Because this type of sensor is self-generating, the sensor does not require power.

Electronic Programmable Transmission Control II (EPTC II) - This is the second generation of the Electronic Programmable Transmission Control that includes advanced diagnostics.

Electronic Unit Injector (EUI) - This is an electro-mechanical fuel injector. The pump, the metering and the injection elements are contained in a single unit. The pump is mechanically actuated and the fuel discharge is electronically controlled.

Electrostatic Discharge (ESD) - This is the release of electrical energy that is caused by the buildup of static between two components.

Engine Speed/Timing Sensor - This is a device that generates a signal that is based on the crankshaft 's: position, speed and direction of rotation.

Erasable Programmable Read Only Memory (EPROM) - This is a type of computer memory that requires special equipment in order to erase stored data. After the device is programmed and then installed the computer can only READ the software program. See Electrically Erasable Programmable Read Only Memory.

Error - This is a type of operator warning that results from a system event (VIMS). See System Event.

ET - See Caterpillar Electronic Technician.

Event - This is a detected failure. The failure may be caused by a sensor that is out of range or an abnormal condition. Events are separated into two basic categories DATA events and MAINTENANCE events. A stored event has a fixed duration (start and end time). An active event is present at the time of troubleshooting. This event has not yet ended so the event has no duration. The conditions that define this event will determine if the event will be stored and/or displayed.

Event Category Indicator (ECI) - This is a designation that shows the event warning category. This is a direct indication of the severity of the event. An example of the indicators are listed here: 1, 2, 2S and 3

Event Count - This is the number of occurrences for a particular eventsince the last reset of the on board data. See Occurrence Count which is the preferred term.

Event Duration - This is the recorded duration of an event that was active.

Event Recorder - This is a six minute recording that was first used with the Vital Information Management System. This term is now referred to as a snapshot recorder. See Snapshot Recorder.

Failure - This is a malfunction of a component or an incorrect calibration of an electronic control system. This condition can occur during normal operation of the engine or machine and AFTER a period of known correct operation. Failures are detected by an electronic control when a signal does not exist or a signal is outside a valid range. Failures usually cause diagnostic information to be stored. However, not all maintenance information represents a failure. A failure is often referred to as a fault. This is an incorrect use of the term. See Fault, Event and Diagnostic Event.

Failure Mode Identifier (FMI) - This is a portion of the total diagnostic code. The FMI identifies a type of failure that is detected by an electronic control. The FMI is a two digit code. The code describes the failure mode of the component that is described by the Component Identifier. A Component Identifier (CID) is always displayed in conjunction with the FMI.

Fault - This is a pre-existing defect in a component or a system. The fault is identified at the initial assembly or at the time of purchase. See Failure. An example of a fault is a PWM sensor that will not function at the time of initial installation.

Flash Files - These software programs contain instructions on the operation of electronic controls. The programs are transferred from the off-board service tool to any on board electronic control. See Flash Programming.

Flash Memory - This is solid state memory that is used in electronic controls. The memory can be reprogrammed with an off-board service tool through a data link without being removed from the control. Other types of memory can only be programmed outside of the control.

Flash Programming - This is a means of programming, reprogramming or updating (uploading) an electronic control with an off-board service tool instead of replacing the control or personality module. This process involves the transfer of configuration software from the service tool to the electronic control. Communication is done over a data link. See Flash Memory and Uploading.

Floating - This describes the end of a circuit that is open. The circuit is not connected to any other component.

Frame Stress Analyzer - This is an attachment to the Vital Information Management System. The system measures the stress on Off-Highway Truck frames and structures. The measurement relates to the condition of the haul roads. This system is actually a monitor of the condition of the haul road.

Fuse - This is a replaceable safety device for an electrical circuit.

Gage - See Gauge.

Gauge - This is a type of display device. The gauge is usually a circular shape with a indicator needle. The gauge can be a mechanical device or a solid state device.

Gauge Pressure (PSIG) - This is the pressure that is measured with respect to atmospheric pressure. See Absolute Pressure.

Ground (B-) - This is the reference point for the electrical system. On CAT products, ground is the machine frame or the engine. This is the connection point for the negative side of the battery.

Grounded Circuit - This is the connection point of any electrical circuit to the machine frame, engine or any part of the machine. This is considered to be the ground reference point for the electrical system. This connection can be either wanted or unwanted (fault).

Ground Level Shutdown - This is a remote means of shutting down the engine without turning off the key switch. This lever can usually be reached from the ground without entering the operator's station (cab).

Hall Effect Speed Sensor (HESS) - This is an active sensor for sensing the speed of slow moving gears or targets. This sensor uses a silicon chip that is called a Hall Cell to sense a moving target.

Hardware (H/W) - This is the electrical components and electronic components that make up an electrical system.

Hard Wired - These permanent connections are made within the wiring harness. These soldered or crimped connections are not meant to be altered.

Harness - This is an assembly or bundle of two or more wires that electrically connect system components. The harness is usually held together by a loom.

Harness Code - This refers to the grounded condition or open condition of the harness code inputs. The harness code provides the characteristics of the machine such as engine oil pressure, maximum engine speed, etc. This code is usually model specific. The VIMS uses this hard wired code in order to determine the module identifier (MID) that is used for data link communications.

Hertz (Hz) - This is a measure of frequency. The units are cycles per second.

Histogram - This is a bar graph that shows the number of occurrences for a given range.

Hysteresis - This is a measure of the lag time that occurs between the turn ON and turn OFF values of a switch or a sensor. An example would be the warning lamp for the oil pressure of the EUI may turn on at 40 psi with decreasing pressure and turn off at 45 psi with increasing pressure. The hysteresis is 5 psi.

I - This is the standard symbol for current. The unit of measure is the Ampere.

Icon - This is a symbol that is used instead of words in order to convey a message in any language.

Indicator - This is a lamp, gauge, etc. The indicator calls attention to service related conditions regarding a machine.

Information System Builder (ISB) - This is a software tool that is used to generate configurations for the Vital Information Management System. The software can also modify existing configuration software. The software can also be used in order to view the items that are listed here: parameters and limits of the parameters. The software can also be used to change the customer values in the Large Wheel Loader Payload portion of the configuration.

Input/Output (I/O) - This describes the electronic circuits within an electronic control that are used for inputs (such as sensors and switches) to the control and the outputs from the control to the external circuits (such as horns, lamps and solenoids).

Instrument Data Link - This is a four-wire Data Link. The Data Link is used with the display modules that are used in monitoring systems.

Interface Module - This is an electronic control that collects information from sensors. The control then sends the results to another electronic control over a data link. The control can also energize output devices such as solenoids.

Jumper - This is a piece of wire that is used to make a temporary electrical connection during troubleshooting.

Keypad - This is a panel of keys that is similar to the one that is used on a push button telephone. The keypad is used as an interface to the on board electrical system.

Key Start Switch - This is a key actuated, automotive type, engine cranking/starting switch including functions such as the ON (relay), CRANK and, sometimes, ACCESSORY.

Kilopascal (kPa) - This is a Metric unit of pressure. The force that is applied to one square meter is one Newton ( 6.89 kPa (1.000 psi)).

kPa - See Kilopascal.

Lamp - This is a component of the machine electrical system that emits light by converting electrical energy into light.

Large Hydraulic Excavator (LHEX) - This is a machine that is usually propelled on tracks. The machine uses hydraulic power to travel. The machine uses hydraulic power to dig up material with a bucket.

LHEX - See Large Hydraulic Excavator.

Large Wheel Loader (LWL) - This is a machine on wheels that moves material with a bucket.

Light Emitting Diode (LED) - This is a solid state device. The device emits light that is visible to the human eye when an electrical current is passed through the device. the LED is used as a lamp in electronic controls because the device is very reliable.

Liquid Crystal Display (LCD) - this is a type of solid state display that uses a liquid crystalline material that is sealed between two glass sheets. An electrical signal causes segments of the crystal material to be visible to the eye.

Load - This is a device that is connected to the electrical system. The load consumes power or the load dissipates power.

Log (Logged) - This is the process of saving information (stored or recorded) within an electronic control. See Store.

LWL - See Large Wheel Loader.

MAC-14 - This is a multipurpose electronic control that contains 14 solenoid driver outputs.

Machine Event - This is an event that describes an abnormal MACHINE condition in the VIMS. Machine events relate to any system except the events that deal with the electrical system. This term is now referred to as a Data Event. See Event,System Event and Operational Event.

Machine Service Connector - This is a harness connector for the machine or engine electrical systems that allow the connection of a service tool.

Message Center Module - This is a VIMS module that contains the main display for the operator warning system. This module also displays information for the service technician.

Module - This is a shortened term that is used in place of the electronic control module. See electronic control module.

Module Identifier (MID) - This is a three digit number that identifies an electronic control.

Non-Volatile Memory (NVM) - This is a type of data storage that is not lost after an interruption of power. See Volatile Memory.

Normal Condition - Normal describes the contact position of a switch or relay. This is the condition when the component is not controlled by the application of the conditions that are listed here:force, temperature, pressure and electricity. This is usually the condition that is found when the component is installed on a machine. This condition can be different when the component has been removed from the machine prior to testing. The Electrical System Schematic shows the condition of the components as the component is installed on a machine. Normal also describes the status of a machine system.

Occurrence Count - This is the number of occurrences for a particular event since the last reset of the on board data. This is the preferred term. See Event Count and Event.

Off-Board - This refers to hardware and software that is located off the machine. The hardware and software can be temporarily connected to the electrical system.

Off Highway Truck (OHT) - This is a hauling unit that is used primarily for off road mining applications.

Ohm - This is the standard unit for measuring resistance. This is represented by the letter "R".

On Board - This refers to hardware and software that is located on the machine as part of the electrical system.

Open Circuit - This is a condition that exists when an electrical circuit is broken.

Parameter - This is a value or a limit that is sometimes programmable. The parameter determines the characteristics or behavior of the engine and/or machine electrical system. A parameter can also refer to the gauge functions and/or the monitored channels of information (Vital Information Management System).

Parameter Identifier (PID) - This is a code that is assigned to each packet of digital information. This code is shared between controls over the CAT Data Link and the American Trucking Association (ATA). Data Link.

Passive Sensor - This is a sensor that does not require external power in order to operate. See Active Sensor.

Password - This is a group of numeric characters or alpha-numeric characters that restrict the access to information in a control system. A password is required by Caterpillar electronic service tools in order to change information.

Personality Module - This is a small module (hardware) or software that is inserted into the engine control which contains all the instructions (software) and performance maps for the engine within a specific horsepower family.

Plug - This is the male end of a connector. The plug makes an electrical connection to a circuit by inserting into a receptacle.

Polled Data - This is data that is requested by an electronic control. The data is not brought in automatically.

Potentiometer (Pot) - This is a variable resistor that has three terminals. The potentiometer can be easily adjusted by using a knob or a screwdriver.

Pounds per square inch (psi) - This is an English unit of pressure measurement. The measurement represents the force that is applied to one square inch. The value is measured in pounds. 6.89 kPa (1 psi)

Pressure Sensor - This is a device that generates a signal that is proportional to the pressure that is sensed.

Pressure Switch - This is a device that senses pressure. The pressure causes the switch contacts to open or the pressure causes the switch contacts to close. This signal can be used by an electronic control. The signal can also be used with a signalling device such as a lamp.

Problem - This is an abnormal machine/engine condition.

Pull up Voltage - This is the voltage that is measured on the input of an electronic control when the input device has been disconnected. (sensor, switch, etc.)

Pulse Width Modulation (PWM) - This is a signal that is made up of a string of pulses that vary in width. The time on versus time off varies according to the system that is being sensed. The frequency of the signal (repetition rate) of the pulses and the height of the signal (amplitude) remain constant.

Quad Gauge Module - This is an display module that contains four analog gauges.

Radio Frequency (RF) - Frequencies that are between about 150 kHz and infrared (invisible light). This range of frequencies are capable of carrying data via radio telemetry systems.

Random Access Memory (RAM) - This is a type of computer memory that is usually volatile. This memory is used for the temporary storage of data.

Read Only Memory (ROM) - This is a type of computer memory that is programmed during the manufacturing process. The memory cannot be reprogrammed later. See Erasable Programmable Read Only Memory.

Real Time - This term is used to describe the relationship of information (events) that is based on a true clock 24 hours represents one day.

Receptacle - This is a female component of the connector that makes an electrical connection to a circuit. The receptacle will receive a plug assembly.

Rectifier - This is an electrical device that converts alternating current into pulsating dc current.

Relay - This is an electromechanical device. The relay uses an electromagnet in order to actuate the electrical contacts. The contacts switch large currents with a relatively small amount of control current to the electromagnet.

Reset - This is a command that restores memory to a default state. The default state is usually zero. This means that all of the data has been removed or erased. See Clear.

Resistor - This is an electrical component. The resistor is usually made of resistance wire or of carbon that has a resistance. Resistance opposes the flow of current.

Rheostat - This is a variable resistor. The rheostat is usually a two terminal version of the potentiometer. The rheostat is often used in applications that require a higher dissipation of power than a potentiometer.

RS-232 Data Link - This is a serial data link that transfers data between electronic devices such as a personal computer and a printer. See Serial Data Link.

Sample Rate - This is the rate or frequency that data is captured and/or stored. This is usually measured in samples per second.

Scroll - This is the process of showing all available sets of event informationwithin a digital display area. The information is shown one set at a time. A set of event information is shown briefly. The display will automatically advance to the next set. After all the sets are shown the process is repeated. Some controls will show the message END before the control repeats the process.

Sender - This is a device that changes resistance according to a physical condition. The sender then sends a signal to a gauge. A single connection provides the signal and the power.

Sensor - This is a device that monitors the physical condition of a machine system. The sensors can monitor the conditions that are listed here: pressure, temperature, flow and mechanical movement. The sensors convert the condition into an electrical signal that can be understood by an electronic control. Also see Transducer and Sender.

Serial Data Link - This is a type of data link that transfers one bit of data at a time. The data link is most often used to transfer information between computer devices.

Service Event - This is a type of maintenance event that requires a service technician to perform service. This is usually routine service that is performed on the machine. Examples of service are changing the engine oil or transmission filters. See Event.

Service Hour Meter (SHM) - This is a meter on the machine that totals the hours when the engine is running .

Service Meter Hours (SMH) - This meter increments time only when the engine is running. This meter is most often used in order to determine the intervals for servicing the machine. This meter is also used to identify the time of occurrence of an event. This is used as part of the diagnostic process. Also see Service Meter Units.

Service Program Code (SPC) - These codes are entered into the electrical system by the user through the keypad. The codes initiate the requested operation.

Service Tool - This is a tool that is used in order to service Caterpillar machines. This term most often refers to the service equipment that is listed here: Electronic Control Analyzer Programmer (ECAP), Caterpillar Electronic Technician (ET), a digital multimeter and laptop computer This may also refer to any other dedicated service equipment.

Service Tool Connector - See Machine Service Connector.

Short Circuit - A connection between two points in a circuit that is normally unwanted.

Signal - This is the changing voltage that is used to carry information. A signal is typically sent from a sensor to an electronic control. For example, a signal is sent from the transmission output speed sensor (TOS) to the transmission control.

Signal Wire - This is the harness wire that carries the signal voltage to the electronic control. The signal is sent by any of the components that are listed here: a sensor, a switch and any other similar components.

Snapshot Recorder - This is a set of machine information that is captured and stored for later use by the service technician. The snapshot is similar to a picture of information. The picture often contains multiple channels over a given time period. This was formerly called an event recorder in the Vital Information Management System. The snapshot recorder that is used by the Vital Information Management System records data for six minutes. This six minute period contains five minutes of information before the event started and one more minute after.

Software (S/W) - This is a step-by-step instruction that defines the operation of a computer system. This is often called a program.

Solenoid - This is a coil assembly that is used to perform some type of mechanical work. The solenoid converts electrical energy into linear mechanical motion with an electrical coil (electromagnet) that produces a magnetic field around an armature (slug or plunger).

Solenoid Valve - This is a device that uses a solenoid in order to actuate a valve (hydraulic or pneumatic). The valve is used to control the flow or pressure of a liquid or gas.

Solid State - This refers to circuits or components that use semiconductors. Examples of solid state devices: transistors, diodes and integrated circuits (IC).

Source Software - This is software that contains detailed operating instruction for the on board system. This is software that is similar to the operating system that is used with a personal computer.

Sourcing Driver - This is a type of output of an electronic control. When the driver (output) is on +Battery is supplied to the load. The other connection must be connected to ground. This is sometimes referred to as a high side driver.

Speed Burp - This is a sudden unwanted change in engine speed.

Speedometer/Tachometer Module - This is a display module that contains the components that are listed here: speedometer for machine ground speed, a tachometer for engine speed and a display for actual gear.

Store - This is the process that is used to record the event information in an electronic control. See Log.

Subsystem - This is a system that is part of a larger system.

Supply Voltage - This is a constant voltage that is supplied to a component such as a sensor. The supply voltage provides the electrical power for the operation of the component. The voltage may be generated by the electronic control or supplied from the machine electrical system.

Sure-Seal Connector - This is a multi-contact connector that holds pins and sockets in a rubber housing.

Suspension Cylinder Pressure Sensor - This is a device that generates a signal that is proportional to suspension cylinder pressure. This sensor is a digital type. The signal changes frequency as the pressure changes.

Switch - This is a device with electrical contacts that opens under specified conditions. This is a device with electrical contacts that closes under specified conditions.

Switch Input - This is the input to an electronic control that is expecting to be a ground, a open or +Battery.

System Clock - This is a device within a machine or engine electrical system, usually in the monitoring system if present, that synchronizes or forces the clock within each electronic control module on a data link to display the same machine or engine hours. The primary use of this clock is for time stamping of events used for service, maintenance and/or warranty, etc.

System Event - This is an abnormal condition in the ELECTRICAL SYSTEM that has been detected by an electronic control in the Vital Information Management System (VIMS). This term is now called a diagnostic type of maintenance event. See Event and Diagnostic Code.

System Voltage - This is the actual voltage that exists between the positive battery post and frame ground. This is sometimes referred to as +Battery voltage.

Temperature Sensor - This is a device that generates a signal that is proportional to the change in temperature.

Temperature Switch - This is a switch that monitors temperature. The switch sends a signal to an electronic control or signal lamp.

Telemetry - This is a wireless method of broadcasting data between two points. This method most often uses a radio. The mobile unit transfers the data to the data collection area.

Test Probe - This is a device for connecting a service tool in order to test a circuit. The probe provides access to a circuit that is being tested. The probes provide access to the circuit without disconnecting the circuit.

Trend - This is a type of graph that shows the changes of a parameter value over time.

Trigger point - This is the starting point in the process of storing a snapshot. This is also the beginning of an event.

Uncommitted Switch Input - This is a switch input for an electronic control. The function varies according to the application. A harness code or programmable software is most often used to determine the function of these inputs.

Undetected Fault - This is a system event that cannot be detected by the electronic control. The fault must be detected by the operator or a service technician.

Upload - This is the process of transferring a program and/or configuration into an electronic control from an off-board service tool. See Flash Programming and Download.

+V - This is a constant voltage that is supplied to a component that provides electrical power for the operation of the component. The voltage is provided by an electronic control module. The voltage is always less than +Battery.

VIMS-PC - This is a Windows based off-board software. The software is used with a service tool. The service tool communicates with the VIMS through the RS-232data link.

Vital Information Display System (VIDS) - This is an electronic monitoring system that is based on the Vital Information Management System. However, the VIDS has reduced features.

Vital Information Management System (VIMS) - This is a system that is designed to monitor all on board systems for abnormal conditions. The VIMS controls the operator's electronic instrument panel via a special data link.

Volatile Memory (VM) - This is a type of data storage that is lost with a interruption of power.

Warning Category - This describes the severity of an operator warning. This is based on one of three categories.

Wiring Harness - See Harness.

Zener Diode - This is a special diode that conducts current in the reverse direction when this reverse voltage becomes higher than a specified value. When this specified value is reached, the voltage across this diode remains constant.

Caterpillar Information System:

773D, 773E, 775D and 775E Off-Highway Trucks Machine Systems Front Suspension (Cylinder) - Install
D250E Series II and D300E Series II Articulated Trucks Power Train Retarder Solenoid Control Valve - Assemble
773D, 773E, 775D and 775E Off-Highway Trucks Machine Systems Front Suspension (Cylinder) - Remove
D250E Series II and D300E Series II Articulated Trucks Power Train Retarder Solenoid Control Valve - Disassemble
D250E Series II and D300E Series II Articulated Trucks Power Train Retarder Solenoid Control Valve - Install
D250E Series II and D300E Series II Articulated Trucks Power Train Retarder Solenoid Control Valve - Remove
773D, 773E, 775D and 775E Off-Highway Trucks Machine Systems Front Wheel, Bearing and Duo-Cone Seal - Install
773D, 773E, 775D and 775E Off-Highway Trucks Machine Systems Hydraulic Caliper Service Brake - Install
773D Off-Highway Truck and 775D Quarry Truck Transfer Gears
D250E Series II and D300E Series II Articulated Trucks Power Train Retarder Hydraulic Control Valve - Assemble
5130, 5130B and 5230 Excavators, 784B, 785B, 785C, 789B, 789C, 793B and 793C Off-Highway Truck/Tractors and 992G, 994 and 994D Wheel Loaders Vital Information Management System (VIMS) Off-Board Service Tool
784C, 785C and 785C HAA Off-Highway Truck Air System and Brakes Air Control Valve (Pulled Unit)
773D Off-Highway Truck and 775D Quarry Truck Drive Shaft (Main)
D250E Series II and D300E Series II Articulated Trucks Power Train Accumulator (Retarder) - Remove
797 Off-Highway Truck Power Train Transmission Planetary - Disassemble
D250E Series II and D300E Series II Articulated Trucks Power Train Accumulator (Retarder) - Install
938G Wheel Loader and IT38G Integrated Toolcarrier Hydraulic System Bucket and Implement Control
769D Off-Highway Truck/Tractor and 771D Quarry Truck Power Train Drive Shaft (Main)
988G Wheel Loader Power Train Parking Brake - Disassemble
527 Track-Type Skidder Power Train Steering and Brake Control Valve
527 Track-Type Skidder Windows - If Equipped
IT14G Integrated Toolcarrier and 914G Wheel Loader Power Train Hydrostatic System
784C, 785C and 785C HAA Off-Highway Truck Air System and Brakes Gear Pump (Pulled Unit Hydraulics and Rear Brake Cooling)
527 Track-Type Skidder Power Train Steering Clutch and Brake and Foot Brake Controls Linkage
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