Using The 8T1000 Position Indicator Group{0760, 0762} Caterpillar

Introduction

The 8T1000 Electronic Position Indicator Group is a digital readout precision linear measuring gage capable of displaying either inch or millimeter displacement. It replaces mechanical dial indicators and allows readings to be taken in applications where mechanical dial indicators would fail, such as rapidly changing dynamic readings.

The indicator and probe are designed with special filtering for stabilizing dynamic readings. Static measurements can also be taken. The dynamic reading feature allows the fuel injection pump rack position to be monitored on an operating engine so the fuel setting can be monitored while the engine is under load.

The position indicator can also be used on the Fuel Injection Equipment Test Stand as a permanent installation for testing and calibrating fuel injection pumps. A "floating zero" is provided to allow the display to be set to zero anywhere in the measurement range of the probe by pressing a touch switch.

Reference: Caterpillar Service Technology Group Tool Guide.

Components Of The 8T1000 Electronic Position Indicator Group

(1) 6V3072 Carrying Case. (2) SEES5690 Decal (8T1000 Group). (3) 8T5295 Foam Insert. (4) 6V6045 Accessories Case. (5) SEES5575 Decal (ACCESSORIES). (6) 8T1001 Electronic Position Indicator. (7) 6V2198 5486.4 mm (18') Extension Cable (also used in 6V3121 Multitach Group). (8) 8T1002 25.4 mm (1.00") Probe. (9) SEES5691 Decal on Rear of 8T1001 Indicator (not shown). (10) SEHS8623 Instruction for use of the 8T1000 Electronic Position Indicator (not shown).

Optional Items

(11) 5P7366 Power Cable. (12) 8T5268 Power Supply. (13) 8T5111 Adapter Cable. (14) 1P7446 Rack Contact Cable. (15) 8T5297 Probe Cable.

(16) 6V6042 Probe Contact Point Group.

(11) 5P7366 Power Cable for connection to 11 to 40 Volts DC (machine battery).

(12) 8T5268 110/220 Volts AC, 50/60 Hz power supply for diagnostic service tools. Supplies 11 to 20 Volts DC at .30 Amp. max current.

(13) 8T5111 Adapter Cable to allow 1P7446 Rack Contact Cable to be used with the "CONTACT" connector on the position indicator.

(14) 1P7446 Rack Contact Cable. Connects to the rack contact screw on Caterpillar® engines. 8T5111 Cable is also required for use with position indicator.

(15) 8T5297 914.4 mm (36") Probe Cable.

(16) 6V6042 Probe Contact Point Group - Contains straight contact points from 2.18 mm (0.09") long to 120.5 mm (4.74") long. It also has three flat points and a 12.7 mm (0.50") extension. Fits all dial indicators (including the position indicator probe) which have 4-48 threads.

In addition to the 6V6042 Probe Contact Point Group, see the Caterpillar Tool Guide for additional tips.

Features

Digital Readout: A 4 1/2 digit custom LCD (Liquid crystal display) provides a digital display of the measurement value, and has arrows to indicate which functions are being used.

Provisions have been made for adding back lighting for use in dark locations, and a display heater for use in cold climates.

Touch Switch: A front panel touch switch controls the functions of the indicator. It has tactile feel to allow the operator to know when a switch has been pressed hard enough to enter a function.

Remote Readout: A position probe which has the same mounting stem as mechanical dial indicators is connected to the indicator with a cable.

This allows readings to be taken from a remote location such as a dynamometer control room, or from the operators compartment on a machine. Extension cables may be used to locate the probe further from the indicator.

Dynamic Reading: Dynamic readings such as rack position on an operating engine can be taken as well as static measurements. Filtering is included in the indicator to help stabilize rapidly changing readings.

Floating Zero: A ZERO touch switch resets the display to zero at any probe position. The display will then show the distance the probe shaft moves from this zero position and indicate which direction it has moved with a + or - indicator.

Storage Memory: Three separate storage memories record the minimum, maximum, and difference values of the measurement being taken. These values can be displayed at any time, allowing the total travel of the probe measuring shaft to be measured and recorded.

Hold Feature: The value of the display can be held constant for any length of time with the press of a front panel touch switch.

Power: The 8T1001 Indicator is powered with an internal 9 Volt battery. Also, 11 to 40 Volts DC external power can be used for permanent installations or when the battery is low. An AC power adapter is also available to power the indicator.

A power saving feature turns the display off if the probe is not used in 10 minutes, but retains all functions and information in the memories. If the probe is not used in 20 minutes, the indicator will turn itself off, clearing the memories and zero. This auto turnoff feature may be disabled if desired.

Low Battery Indicator: When the internal battery or external power is less than approximately 6 Volts, LO BAT will appear on the display. The accuracy of the indicator will not be affected until the voltage drops low enough to cause a visible effect on the display.

Calibration: The electronic position indicator will maintain it's accuracy for at least one year. The accuracy can be easily checked using a dial bore gauge calibrator or fabricated tool calibrator and readjusted with a single internal adjustment if necessary.

Computer Output: The position indicator has a built in connector which will attach to an optional RS232 computer interface printed circuit board which will be available at a later date.

This will allow a personal computer to display and use the measurement data and also to control the functions of the position indicator with the computer.

Specifications

NOTE: These specifications are with a 25.4 mm (1.00") probe]

Measuring Range: 0 - 25.4 mm (0 - 1.00").

Maximum Prove Travel: 27.4 mm (1.080").

Resolution: 0.01 mm (0.001").

Repeatability: ± 0.00508 mm (0.0002").

System Accuracy: ± 0.025 mm (0.001") accuracy from 5 mm (0.200") to 20.3 mm (0.800") probe shaft travel from fully extended probe shaft position.

± .050 mm (0.002") accuracy from fully extended probe shaft position to 25.4 mm (1.00") probe shaft travel.

Operating Temperature: 8T1001 Indicator -18° to +60°C (0° to 140°F).

Storage Temperature: 8T1001 Indicator -40° to +100°C (-40° to +212°F). 8T1002 Probe 25.4 mm (1.00"): -40° to +150°C (-40° to +300°F).

Internal Power: Standard 9 volt Battery, NEDA 1604, or 6F22 or 006P.

External Power: 11 to 40 Volts DC at 0.007 Ampere.

Battery Life: Alkaline battery; 100 continuous hours nominal, or up to 300 hours intermittent.

Readout Update and Averaging Rate: NORM Rate 3 times per second. SLOW Rate 1 time per second.

Polarity Indicator: Can be changed to indicate either + or - as probe moves in either direction from the zero point.

8T1000 Group Size: 394 mm (15.5") × 311 mm (12.2") × 101 mm (4.0").

8T1001 Indicator Size: 190 mm (7.5") × 112 mm (4.4") × 40 mm (1.6")

8T1002 Probe Size: Length (not including probe shaft) 89 mm (3.5").

Body Diameter 19 mm (0.75").

Mounting Stem Diameter 9.5 mm (0.37").

Mounting Stem Length 21 mm (0.83").

Probe Shaft Diameter 4.75 mm (0.187").

Cable Length 914 mm (36").

Probe Spring Return: 0.11 to 0.17 kg (4 to 6 oz).

Weight: 8T1000 Group 2.15 kg (4.730 lb).

8T1001 Indicator 0.57 kg (1.254 lb).

8T1002 Probe 0.113 kg (0.249 lb).

Adaptability

The 8T1000 Electronic Position Indicator Group can be used on all Caterpillar products to replace all mechanical dial indicators, provided the accuracy of the indicators being replaced, is not better than the position indicator's accuracy.

Connections To The Indicator

(17) Power Input Connector. (18) Rack Contact Connector. (19) Pickup Connector.

(17) Power Input Connector: Connection for external 11 to 40 Volt DC power source. This connection is not required if a good 9 volt battery is installed in the indicator. Use the optional 5P7366 Cable to connect to machine battery. Optional 8T5268 Converter connects here for 110/220 Volt AC operation.

(18) Rack Contact Connector: For static governor rack adjustment. When connected to engine rack contact screw, arrow will appear on display and point to CONTACT to indicate full rack. Use 8T5111 adapter cable to connect to a standard 1P7446 Rack Contact Cable.

(19) Pickup Connector: Install 8T1002 Probe or other optional pickup here. One or more 6V2198 extension cables (used in 6V3121 Multitach Group) may be used for remote readout. Extension cables do not affect the accuracy of the indicator.

Indicators On The Electronic Position Indicator

(20) Digital Display: Liquid crystal display with automatic decimal point positioning. Display is automatically reset to zero when unit is turned on if power has been off for more than 20 minutes.

(21) LO BAT Indicator: Turns on when internal 9 Volt battery voltage drops to 6 Volts. At this time, approximately 10 hours of battery life remain. Without an internal battery, it will indicate when the external voltage applied to the 11 to 40 Volt DC connector is too low.

NOTE: An arrow will appear on the display next to the label to indicate the following functions.

(22) MM Indicator: Indicates when display is indicating in metric (millimeter) units.

(23) INCH Indicator: Indicates when display is indicating in English (inch) units.

(24) CONTACT Indicator: Indicates a closed circuit (less than 200 Ohms) on the CONTACT input cable.

(25) ACTUAL Indicator: Indicates the value shown is the actual distance the probe shaft has traveled from the zero point.

(26) DIFF Indicator: Indicates the value shown is the difference value between the values stored in the minimum and maximum memories.

(27) MAX Indicator: Indicates the value shown is the maximum distance the probe shaft has traveled in the positive (+) direction from the zero point.

(28) MIN Indicator: Indicates the value shown is the minimum value, which is the distance the probe shaft has moved in the negative (-) direction.

(29) SLOW Indicator: Indicates the display is being updated at the rate of once per second and the value shown is a one second average value.

(30) NORM Indicator: Indicates the display is being updated at the normal rate of 3 times per second.

(31) -Indicator: Indicates the - sign on the display will appear whenever the probe shaft moves out, and the + sign will appear whenever the shaft moves into the pickup body from the ZERO position.

(32) + Indicator: Indicates the + sign on the display will appear whenever the probe shaft moves out, and the - sign will appear whenever the shaft moves into the pickup body from the ZERO position.

(33) HOLD Indicator: Indicates the value on the display is being held and will not change even if the probe shaft moves.

Touch Switch Controls On The Electronic Position Indicator

NOTE: The touch switches must be pressed and held until the display shows a change has been made.

(34) + Pushbutton: After pressing, display will indicate + whenever the probe shaft moves out and - whenever the probe shaft moves into the pickup body from the dynamic ZERO position. Arrow will appear on the display next to the + label.

(35) - Pushbutton: After pressing, display will indicate - whenever the probe shaft moves out and + whenever the probe shaft moves into the pickup body from the dynamic ZERO position. Arrow will appear on the display next to the - label.

(36) MM Pushbutton: Changes the value on the display to a Metric value in millimeters. Arrow will appear on the display next to MM.

(37) INCH Pushbutton: Changes the value on the display to an English value in inches. Arrow will appear on the display next to INCHES.

(38) MIN Pushbutton: Shows the minimum value on the display, which is the most - (negative) value the probe shaft has moved to. Arrow will appear on the display next to MIN.

(39) MAX Pushbutton: Shows the maximum value on the display, which is the most + (positive) value the probe shaft has moved to. Arrow will appear on the display next to MAX.

(40) DIFF Pushbutton: Shows the difference value on the display, which is the distance between the MIN and MAX values, or total distance traveled by the probe since the CLEAR pushbutton was pressed. Arrow will appear on the display next to DIFF.

(41) ACTUAL Pushbutton: Shows the ACTUAL value on the display, which is the current distance the probe has moved in a + or - direction from the ZERO point. An arrow will appear on the display next to ACTUAL.

(42) CLEAR Pushbutton: Clears the MIN, MAX, and DIFF memories to zero if pressed when the ACTUAL value is 0000. If the CLEAR pushbutton is pressed when a value other than 0000 is on the ACTUAL display, that value will be entered into the MIN and MAX memories and the DIFF will show 0000.

(43) SLOW RATE: Causes the display to be updated every second with a one second average value. Arrow will appear on the display next to SLOW. SLOW RATE is useful to slow the display reading when it is changing rapidly.

(44) NORM RATE: Causes the display to be updated three times per second (NORM update rate). Arrow will appear on the display next to NORM.

(45) ZERO Pushbutton: Resets the ACTUAL display to ZERO (.000) for the current probe position. This sets the floating ZERO position of the probe.

(46) HOLD Pushbutton: When pressed, the reading on the display will not change. Arrow will appear on the display next to HOLD.

(47) HOLD CLEAR: If the reading on the display is being held, this pushbutton will allow the reading to update to the current value. The arrow next to HOLD will be removed when pressed.

(48) OFF Pushbutton: When pressed, the display will go blank and the indicator will go into a low power mode which saves all information and pushbutton settings for 20 minutes. If the indicator is not turned on in 20 minutes, the power will be turned off and all memory will be lost.

(49) ON Pushbutton: Turns the indicator ON. If the indicator has been off for less than 20 minutes, the display and functions will remain as they were before turn off. If the indicator has been off for more than 20 minutes, the display will show all segments on it for a short time, then have a random number on it, and then reset to ZERO, automatically. The MIN, MAX, and DIFF memories will be cleared. All other functions will turn on in the mode they were in the last time the indicator was used.

Powering The Electronic Position Indicator

There are three methods of powering the Position Indicator. They are as follows:

1. Internal 9 Volt battery for portable use.

2. External 11 to 40 Volts DC from machine battery.

3. AC power operation using 8T5268 Power Supply.

Internal Battery Operation

The Position Indicator is normally operated from the internal 9 Volt battery. If this battery is installed and in good condition, the indicator will operate whenever the ON touch switch is pressed.

When the battery voltage drops to 6 Volts, and approximately 10 hours of life remain, the words LO BAT will appear on the display. As soon as possible, the internal battery should be changed using the procedure which follows.

NOTE: After the LO BAT signal appears, the indicator will still be accurate until the battery voltage is so low that the display will not change or missing segments appear.

Replacing The Internal Battery

1. Remove six screws (50) from the rear cover and remove the cover (51).

2. To remove the battery, pull up on battery (52) and remove it from the holder.

3. Install a new 9 Volt battery in the battery holder.

NOTE: BE SURE THE + TERMINAL ON THE BATTERY IS ON THE + (RED TERMINAL) ON THE HOLDER.

4. Install rear cover (51) and install six screws (50).

Operation On External 11 to 40 Volts DC From Machine Battery

1. Use a 5P7366 Power Cable (11). This cable is the same 5486.4 mm (18') power cable used with the 6V3121 Multitach Group.

2. Connect power cable (11) to 11 to 40 Volt DC connector (17) on the top of the position indicator.

NOTE: When using the battery on a machine or engine to power the position indicator, ALWAYS CONNECT ONE OF THE INPUT CABLE CLIPS TO THE FRAME OF THE MACHINE and the other clip to the battery + (positive) terminal. Since the 11 to 40 Volt DC connector is non-polarized, either clip can be connected to either the + (positive) or machine frame.

3. If the machine is equipped with a disconnect switch, it must be turned on to supply power to the position indicator. Once power has been supplied, the position indicator will operate whenever the ON touch switch is pressed.

Fuse Replacement

If the position indicator will not operate when connected to an external 11 to 40 Volt DC source, the internal fuses may be burned out. To check and replace these fuses, follow this procedure.

1. Remove six screws (50) from the rear cover, and remove the cover (51) from the indicator.

2. Locate two fuses (53) on the printed circuit board directly behind the 11 to 40 Volt DC connector. Use a 6V3030, 6V7800, or 6V7070 Digital Multimeter to check these fuses. They can be left in their holders for the check.

Put the multimeter on the 200 Ohm scale and measure from one end of one fuse to the other end of the same fuse. A good fuse will measure less than 1 Ohm resistance. A defective fuse will measure infinite Ohms (OL on the multimeter display) and should be replaced.

Be sure to check both fuses. The fuse should be replaced with an 8K4644 Fuse or a 1 amp, 250 Volt fuse of the same type.

AC Power Operation

1. Move switch (54) on the rear of the 8T5268 Power Supply (12) to the correct AC line voltage, either 120 Volts for U.S.A. operation or 230 Volts for non-U.S.A. operation.

2. Connect the power supply connector (55) to the 11 to 40 Volt DC connector on the position indicator. Plug the power supply connector (55) for U.S.A. operation to the 11 to 40 Volt DC connector on the position indicator. Plug the power supply into an AC outlet.

For operation outside the U.S.A., an AC power plug adapter may be required.

3. Once power has been supplied, the position indicator will operate whenever the ON touch switch is pressed.

Operation Instructions

Hookup And Use Of The Position Indicator

These instructions are for general use of the position indicator. More specific application instructions are contained in the next section.

1. The 8T1002 Probe is the standard sensor for the position indicator. It mounts in the same manner as a mechanical dial indicator mounts and can use most of the same mounting fixtures.

2. Before using the probe, the correct tip (56) must be installed in the end of the shaft (57). The end of the shaft has AGD 4-48 internal threads which will accept most standard dial indicator tips. The tips should be installed finger tight only.

Since the shaft rotates, it may be necessary to use a tool to keep it from turning when removing a tight tip. If this is done, the shaft must be protected with a cloth and extreme care taken so the shaft is not scratched.

The probe has a standard 9.52 mm (.375") diameter mounting stem (58). The probe should always be mounted using this stem.

3. The probe has a short cable (59) which connects to the PICKUP connector on the position indicator. If a longer cable is required, use either a 6V2198 Cable Assembly 5486 mm (216") or an 8T5297 Cable Assembly 914 mm (36").

Several of these cables connected together can be used without affecting the accuracy.

4. Refer to the section "Powering the Electronic Position Indicator" to select the desired power source for the indicator. Once power has been supplied, press the ON switch and the display will come on to show the unit is working.

5. The position indicator has a circuit which will automatically turn the display off to save power if the probe shaft has not moved in 10 minutes. The display can be restored by simply pressing the ON switch.

If less than 20 minutes have passed since the unit was automatically turned off, the original set up will be remembered. If the indicator is off more than 20 minutes, the ZERO must be reset and the data in the memories will be lost.

NOTE: Refer to the section "Disabling the Auto Turn-Off Feature" if necessary.

6. After turn-on, select the following settings with the front panel touch switch:

* Press the ACTUAL switch.

* Select MM or INCH reading.

* Select + or - (+ for + sign when shaft moves out from zero) (- for - sign when shaft moves out from zero).

* Select NORM RATE or SLOW RATE for update frequency.

* Press HOLD CLEAR if HOLD arrow is on.

* Once these initial settings are made, the indicator will stay on these settings until they are changed or the internal battery is discharged or removed, even when the indicator turns off.

* Mount the probe using mounting stem (58) so the shaft can be removed over the entire measurement range without reaching the end of the shaft travel.

Position the probe shaft at the mechanical zero, which is the setting the measurements are to be referenced from. After this mechanical zero has been established, the display on the indicator can be set to zero by pressing the ZERO switch on the front panel.

* Once the previous initial settings have been made, an arrow on the display should point to ACTUAL, then position readings can be read on the display. The display will show the exact distance the probe shaft has moved from the electrical zero point.

If the NORM RATE arrow is on, then a new reading will be taken three times a second; and if the SLOW RATE arrow is on, a reading will be taken once every second. The slow rate is helpful to stabilize the display when taking dynamic readings which are changing rapidly.

* Measuring MIN (Minimum), MAX (Maximum), and DIFF (Difference): These three values are defined as follows:

A. MIN - The distance the probe shaft has moved from the zero position in the - direction.

B. MAX - The distance the probe shaft has moved from the zero position in the + direction.

C. DIFF - The total distance the probe shaft has moved from the min value to the max value. The position indicator has built in memories to store these three values.

The value of each can be viewed by pressing the MIN, MAX, DIFF switch. To make these values accurate readings, the memories must be cleared by resetting them to zero.

To do this, press the ACTUAL switch and move the probe shaft back to the zero position so the display reads exactly 000. Press the CLEAR switch and the memories will be cleared. MIN, MAX, and DIFF readings will now automatically be taken and stored in the memory. To view any of these values, press the desired switch and the value will appear on the display.

* Measuring deviation using the MIN, MAX, and DIFF functions: The memories are useful for showing how much the dimensions of several similar parts vary from part to part, or for recording how much a position has changed from an initial set point.

To record deviation, set the ACTUAL display to ZERO at the zero reference point of the part or position to be measured, then move the probe to the desired position to be measured on the part. With the display showing the ACTUAL value of the point being measured, press the CLEAR touch switch to reset the memories. The MIN and the MAX memories will then show the same reading as the ACTUAL reading and the DIFF memory will show zero.

When the probe is moved, the MIN and MAX memories will show the lowest and the highest values the probe moves to. The DIFF memory will show the total distance the probe travels, or deviation.

To keep from changing the memory values during adjustments or while changing from one piece part to another, press the HOLD touch switch. After the part has been changed, press HOLD CLEAR to start taking measurements again. Any movement of the probe is not recorded when HOLD is on.

Using The Contact Feature Of The Position Indicator

NOTE: The electronic position indicator has a built-in continuity test feature. This feature should NOT be used to replace the 6V4060 Engine Set Point Indicator.

The contact feature of the position indicator can be used for locating the full load fuel setting on a non-operating engine. When continuity is made on a cable connected to the CONTACT connector, an arrow will appear next to the CONTACT label on the display.

1. Plug 8T5111 Adapter Cable (13) into the RACK CONTACT connector (18) on the position indicator. Connect 1P7446 Rack Contact Cable (14) into connector (60) on the end of the adapter cable.

2. Turn the indicator on. Touch the two clips (61) and (62) on the end of rack contact cable (14) together and an arrow should appear on the display next to the word CONTACT. This arrow will come on anytime there is less than 200 Ohms of resistance between the cable clips.

3. When measuring the static fuel settings on a non-operating Caterpillar engine, it is helpful to know when the rack has made contact with the torque spring group. Most Caterpillar engines have an electrical contact on the governor which closes when this occurs.

To use this contact, connect the small insulated clip (62) on rack cable (14) to this contact, and the large uninsulated clip (61) to the unpainted metal protrusion on the engine.

The contact arrow (63) will then come on when the rack makes contact with the torque spring group. The contact arrow indicator (63) will stay on even when the governor control is moved to place the rack in the full torque position.

At these indicated positions, the actual rack setting values can be obtained from the digital display.

Checking Engine Dynamic Fuel Settings

Since the electronic position indicator is designed for dynamic as well as static measurements, it can be used to measure the fuel settings on operating diesel engine fuel injection pumps on the engine or on the fuel injection equipment test stand. This allows rapid measurement of the actual fuel setting during engine operation.

This feature is very useful in diagnosing engine power complaints and fuel system related problems. In addition to measuring the fuel settings, the dynamic fuel ratio control settings can easily be checked after they are activated.

Mounting the indicator probe on the engine for taking dynamic measurements is simplified because the probe has the same mounting dimensions as mechanical dial indicators. This allows standard rack measurement fixtures to be used for mounting the probe.

When using these fixtures for operating engine tests, some engine lubricating oil may leak out of the engine through the unsealed rack fixtures. This will not cause a problem for short duration testing, but may for longer tests.

The following is a general procedure for using the electronic indicator to measure the rack settings on Caterpillar diesel engines. Following this general procedure, specific information on each fuel system type is provided.

If adjustments to the rack settings are required, the actual static rack setting procedures found in the rack setting Special Instruction should be used.

1. Obtain the proper rack position tool group for the engine to be measured and the Special Instruction relating to that tool group. Follow the instructions outlined in the tool group Special Instruction, but replace the dial indicator with the 8T1002 Probe from the 8T1000 Electronic Position Indicator Group.

Before proceeding, read the section "Hookup and Use of the Position Indicator" in this Special Instruction to become familiar with the operation of the position indicator.

2. Install the rack test fixture on the engine to be tested. Before installing the 8T1002 Probe in the rack test fixture, connect it to the position indicator. Press the ACTUAL touch switch to set the display to .00 mm (.000") by pressing the ZERO touch switch with the probe shaft out all the way. Install probe in the fixture, and tighten loosely.

3. Move rack from shut off position to high idle by hand while watching the digital display. The display should always read more than .00 mm (.000"), but less than 25.40 mm (1.000").

Readjust the probe position in the test fixture, if required, to make the readings stay within this range. When the readings are within this range the probe is properly positioned, it should be tightened in the fixture.

4. Center the rack using the spacer or method described in the Special Instruction. Set the digital display reading to 0.00 mm (0.000") by pressing the ZERO touch switch.

5. Remove the spacer and move the rack to full rack position.

The digital display should indicate a (+) number if the fuel setting is a positive setting, or a (-) number if the fuel setting is a negative setting. If it indicates incorrectly, press either the (+) or (-) touch switch to change the display.

6. The digital display will now show the actual rack setting with positive values shown for movement on the full rack side of center and negative values for the shut off side of center.

Start the engine and observe the rack settings on the digital position indicator. Full load rack settings can be obtained by loading the engine with a dynamometer or machine implements. The dynamic fuel settings are slightly different than the static fuel settings and are listed in the Fuel Setting Microfiche Libraries, SBFY1106 and SBFY1107, and Fuel Setting and Related Information, SBFY1108.

Rack readings are usually taken with the position indicator in the NORM operating rate (an arrow on digital display points to NORM). However, if the readings vary too much, the SLOW RATE switch can be pressed to make the display easier to read. The SLOW RATE arrow will show on the display. The MIN, MAX, and DIFF switches can also be used.

Specific Instructions For Various Types Of Caterpillar Fuel Systems

Sleeve Metering Fuel Systems (Static Test Only)

Engines with sleeve metering fuel systems do not have a dynamic fuel measuring or setting procedure. Do NOT attempt to use the 8T1000 Position Indicator Group on these engines with the engine operating.

For standard static fuel setting measurements, replace the existing dial indicator with the position indicator. The 3208 engine requires the 57.2 mm (2.25") 5P6531 extension tip on the 8T1002 Probe.

Scroll-Type Fuel Systems (Including The New Series)

Engines with scroll-type fuel systems can be checked under both dynamic and static conditions. Use the standard rack settings, fixtures, and procedures, but replace the dial indicator with the position indicator. On these engines, the position indicator can be used under actual engine operating conditions to evaluate full fuel rack movement during operation.

It can also indicate when the torque spring goes completely flat in all applications and the engines natural torque rise characteristic is encountered. This will assist in evaluating low horsepower complaints at low engine speeds.

Using The Position Indicator On The Fuel Injection Test Stands And Test Benches

For use of the position indicator on the fuel test stands and benches, use the previous instructions for on engine testing.

The indicator may be permanently mounted on the fuel test stand with the internal battery removed. Use the 8T5268 AC Power Supply used to provide power to the indicator, or use the 5P7366 Cable and connect to the built-in power supply of the Fuel Injection Equipment Test Stand and Test Benches.

The auto turn-off feature can be disabled if external power is used. This will prevent the display from going blank during periods when the fuel pump is not operating.

Checking Dynamic Fuel Ratio Control Settings

Once the electronic position indicator has been installed on an operating engine, it can easily be used to check the setting of the fuel ratio control while the engine is operating.

Before starting the engine, set the rack on the mechanical zero position. Press the ZERO switch to set the display reading to .000, then press the CLEAR switch to clear the memories. Next, start the engine and activate the fuel ratio control and remove the air line to it.

Make the measurement by moving the governor control lever rapidly from low idle to high idle position. Hold at high idle position for a short period of time and release. Press the MAX touch switch to read the fuel ratio control setting which is the maximum distance the rack was allowed to move.

If the fuel ratio control is completely moved forward by air pressure, the "MAX" function can be used to measure the dynamic full torque rack position.

Checking The Operation Of The Position Indicator With The 8T1002 Probe

The following procedure can be used to check the operation of the position indicator. This procedure is intended to be a function check and not an accuracy check. However, it does give an indication of the condition of the indicator.

The only components required for the test are the 8T1001 Indicator and the 8T1002 Probe. Follow the steps listed below to perform the test. If the display turns off during the test, press the ON switch again.

1. Refer to the section "Powering the Electronic Position Indicator", and provide power from one of the three sources listed. For a complete check, this test should be repeated using all three power sources.

2. Plug the 8T1002 Probe into the PICKUP connector. During the following tests, the probe shaft must not be moved unless the instructions call for it. Also, during the following steps, whenever a touch switch is pressed, an arrow should appear on the display next to the label corresponding to the switch pressed.

3. Press the ON switch. After the display comes on, press the ACTUAL switch, and then the INCH switch. If there is an arrow next to HOLD on the display, press HOLD CLEAR to remove it.

4. Pull the probe shaft to make sure it is out as far as it will go. Press the ZERO switch. The display should now read .000.

5. Press the (+) switch and the MIN switch. Press the CLEAR switch and the display should read (+) or (-).000.

Move the shaft of the 8T1002 Probe into the probe body as far as it will go. The display should show a value of at least 1.000 as the MIN reading.

Press MAX and the display should read .000. Press DIFF and the display should show at least 1.000. Press ACTUAL and the display should read .000 again.

6. Press the (-) switch and the MIN switch. Press the CLEAR switch and the display should read .000.

Move the probe shaft into the probe body as far as it will go and then pull it out as far as it will go. The display on MIN should remain at .000.

Press MAX and the display should read at least 1.000. Press DIFF and the display should stay the same. Press ACTUAL and the display should read .000.

7. To check the MM function, repeat Step 6 with the MM switch pressed. The display should read at least 25.40 mm (1.000") for the value readings and the zero reading should be .00 mm (.000").

8. To check the NORM RATE function press the ACTUAL switch and move the probe shaft in and out rapidly. The number on the display should change rapidly (approximately 3 times per second).

Press the SLOW RATE switch and move the probe shaft. The number on the display should change much slower (once per second).

9. The HOLD function can be checked by moving the probe shaft until any number appears on the display and holding the shaft in that position.

Press the HOLD switch and release the shaft. The number should remain on display until the HOLD CLEAR switch is pressed.

10. To check the automatic turn-off feature of the position indicator, turn the indicator ON and note the arrows and reading on the display. After 10 minutes of no probe shaft motion, the display should go blank.

When this happens, turn the indicator ON again and check to be sure the display is the same as before the unit turned off. To check the 20 minute turn-off feature, let the unit set for at least 20 minutes before removing the probe shaft or pressing any switches.

After 20 minutes, turn the unit ON and read the display when MIN, MAX, DIFF, and ACTUAL switches are pressed. The display should read .000 on all of these to indicate the memories have been cleared.

NOTE: If the auto turn-off feature does not work, be sure it has not been disabled. Refer to the section "Disabling the Auto Turn-Off Feature".

11. To check the CONTACT feature, use an 8T5111 Adapter Cable and a 1P7446 Rack Contact Cable. Plug the adapter cable into the CONTACT connector and the rack cable into the other end of the adapter cable.

Touch the clips on the end of the rack cable together and an arrow should appear on the display next to CONTACT. When the clips are not touching each other, the arrow should not show.

Calibration

The position indicator accuracy should be checked periodically to be sure it is still accurate and meets specifications.

Since a standard Caterpillar dial bore size setting fixture group is used to check the calibration, most dealerships already have the primary equipment required for the calibration of the position indicator. If a dial bore size setting fixture group is not available, a test fixture can be made in a machine shop using a fabricated tool drawing which is available from Caterpillar.

If the calibration check shows the indicator needs adjustment, a simple internal adjustment is all that is required. Use the following procedure to check the accuracy.

Installing Probe In 1P3536 Test Fixture

1. Install the 3S3270 44.5 mm (1.75") long tip (66) in the end of the position indicator probe.

2. Place 8T5108 Bushing (65) over the end of the probe mounting stem with the end of the bushing with the largest inside diameter closest to the probe body. Install the bushing so it is even with the end of the mounting stem.

3. On the 1P3536 Size Setting Fixture, turn the micrometer dial (64) out (counterclockwise) until it reads 0.0.

4. Using a 1/16" Allen wrench (70), turn the Allen screw on the lower end of the holder arm (71) counterclockwise until the arm is free to pivot when pressed on the lower end near the Allen screw.

5. Slide holder arm (71) away from the micrometer head as far as it will go until it hits the stop at the end of it's mounting rod.

6. While pressing the lower end of the holder arm (71), insert the probe tip into the V-groove (72) with the probe tip against the micrometer spindle face (73). Keep bushing (65) even with the end of the probe mounting stem and under holder arm (71).

With one hand, keep the probe tip against the micrometer spindle face (73). With the other hand, pull back on the probe body to be sure the probe shaft is out as far as it will go.

Tighten holder arm Allen screw (74) by turning it clockwise until the probe is securely held in the V-groove. The probe is ready to check.

NOTE: This setting procedure is very critical and should be checked by turning the micrometer dial one turn counterclockwise so the micrometer spindle face (73) no longer touches the probe tip.

Pull out on the probe tip; and while holding it out, turn the micrometer dial slowly, one turn clockwise back to 0.0. The probe tip should not touch the spindle face (73) until the micrometer is at 0.0.

Readjust the probe position if required so the probe shaft is out as far as it will go, at exactly 0.0.

If the FT1982 Calibration Fixture is being used, the probe mounting boss will fit directly into the hole in the sliding mounting plate, and can be tightened with the bolt on top. The bolt on the side of the probe mounting plate allows the plate to be slid to the proper position during the checking and calibration procedures.

A short tip should be used on the probe shaft when using this fixture. The probe should be positioned as described in Step 6.

Checking The Accuracy

Once the probe has been installed in a test fixture, the accuracy of the system can be checked by adjusting the micrometer to move the probe shaft over it's entire range. The readings of the position indicator can be compared with the micrometer at various intervals and the difference noted. This will be the system accuracy.

Although the indicator display only shows .001" resolution, the accuracy can be read to .0001" resolution by turning the micrometer dial until the least significant digit changes on the display and reading the error from the micrometer dial.

1. The probe has 25.4 mm (1.00") of accurate travel starting with the shaft out as far as it will move. The previous installation procedure aligns the probe in the fixture so this range can be accurately checked.

2. Turn the indicator ON and set it up to take ACTUAL readings in inches or mm so the indicator readings are the same units as the micrometer.

3. Adjust the micrometer to read 0.0. Press the ZERO switch on the indicator so the display reads zero.

4. Turn the micrometer dial counterclockwise and note the readings of the indicator at 10 mm (.1") intervals. During the check it may be necessary to move the probe shaft in and out slightly by hand before taking readings to be sure it is not binding. Record the readings at each interval.

5. When the micrometer reaches the end of its marked range of 25 mm (1.00"), reset the zero on the position indicator by pressing the ZERO switch. Repeat the check in the other direction by turning the micrometer dial clockwise.

6. The values recorded in Steps 4 and 5 above, should agree with the micrometer settings within the specified accuracy of the position indicator. If the error exceeds specifications, the position indicator may be calibrated with the following procedure.

However, if possible, it is best to check another probe before calibrating the indicator, to determine if the problem is a bad probe.

Calibrating The Position Indicator

1. Remove the six screws (50) and remove the rear cover (51). Locate calibration adjustment (75) on the small printed circuit board. A small screwdriver is required to turn the adjustment screw.

2. With the probe installed in a test fixture as specified in the section "Checking the Accuracy", the calibration adjustment can be used to adjust the indicator so the readings will be within specifications when performing the accuracy check.

If the readings are low, turn the adjustment clockwise, and if the readings are high, turn the adjustment counterclockwise. Only 1/2 to 1 turn should be required to bring the indicator into calibration.

Each time after turning the adjustment screw, the ZERO must be reset and the accuracy rechecked. Recheck the accuracy over the entire range of the probe.

3. If several different probes are used with the indicator being adjusted, check for accuracy with each probe. The adjustment may have to be readjusted slightly to make the indicator accurate with all the probes.

Disabling The Auto Turn-Off Feature

To lower battery consumption, the position indicator is designed to turn off automatically if it is not being used. In permanent type installations such as on a fuel test bench, this feature may be undesirable.

Provisions have been made to disable auto-turn-off so the indicator will turn off only when the front panel OFF touch switch is pressed. To disable this feature, follow the instructions on the following page.

1. Remove the rear cover as shown in step 1 of "Calibrating the Position Indicator" above.

2. Remove four screws (76) located on the corners of top small printed circuit board (77). Remove small printed circuit board (77) by using a small screwdriver to separate the circuit board connector.

NOTE: Use care not to damage the conductors on the bottom of small circuit board (77) when prying it up.

Once the connector is loose, small circuit board (77) can be lifted off and the connector panel will come off with it, leaving the large printed circuit board below exposed.

3. Locate the auto turn-off connector (78) on the printed board. It is between the battery and the 40 pin integrated circuit. Lift off the connector and move it over to the next set of pins (closest to the battery) to disable the auto turn-off feature.

The diagram above shows the proper location of the connector for each mode of operation. To change the auto turn-off mode, move the connector back to the two pins closest to the 40 pin integrated circuit.

4. Carefully reinstall small printed circuit board (77) on top of the large circuit board. Make sure the connector between the boards is properly aligned before pressing them together. Install four screws (76) in the corners of small board (77) and install the rear cover.

Repair Of The 8T1000 Electronic Position Indicator

If the electronic position indicator does not operate correctly, replace the internal battery with a new one and check the operation of the indicator using the procedure in the topic Checking the Operation of the Position Indicator.

If the position indicator is found faulty, it can be returned to Caterpillar Service Technology Group for service. The 8T1002 Probe should also be returned with the faulty indicator.

A letter should accompany the returned unit, stating the problem and the date of purchase from Caterpillar. Units less than one year old will be repaired under warranty (except for abuse). Cost of out-of-warranty repairs will be charged to the owner. Send the Position Indicator and Probe to one of the following addresses: