Supplemental Documentation for the Payload Control System{7494} Caterpillar

Integrated Toolcarrier:

IT38G Series II (S/N: CSX1-UP)

IT62G Series II (S/N: AYA1-UP)

IT38G (S/N: 7BS1-UP; 1CW1-UP)

IT62G (S/N: AKP1-UP; 6PS1-UP)

Wheel Loader:

966F Series II (S/N: 1SL1-UP; 9YJ1-UP)

980C (S/N: 63X1-UP)

980F (S/N: 8CJ1-UP)

988B (S/N: 50W1-UP)

988F Series II (S/N: 2ZR1-UP)

988F (S/N: 8YG1-UP)

990 (S/N: 7HK1-UP)

992D (S/N: 7MJ1-UP)

994 (S/N: 9YF1-UP)

994D (S/N: 3TZ1-UP)

938F (S/N: 1KM1-UP)

970F (S/N: 7SK1-UP)

980F Series II (S/N: 8JN1-UP)

928G (S/N: 6XR1-UP; 7SR1-UP)

938G Series II (S/N: RTB1-UP; CRD1-UP; PHN1-UP)

938G (S/N: 4YS1-UP; 6WS1-UP; 8RS1-UP; 9HS1-UP)

950F Series II (S/N: 5SK1-UP; 8TK1-UP; 2LM1-UP)

950F (S/N: 7ZF1-UP; 6YG1-UP)

950G Series II (S/N: BAA1-UP; AYB1-UP; AYD1-UP; AYL1-UP; AXR1-UP; AYS1-UP; AXX1-UP)

950G (S/N: 2JS1-UP; 4BS1-UP; 6NS1-UP; 3JW1-UP; 5FW1-UP; 5MW1-UP; 8JW1-UP)

950H (S/N: N1A1-UP; M1G1-UP; J5J1-UP; K5K1-UP)

960F (S/N: 9ZJ1-UP; 4CL1-UP; 6XL1-UP; 1YM1-UP)

962G Series II (S/N: BTA1-UP; BAB1-UP; BAC1-UP; BAD1-UP; AYE1-UP; AYG1-UP; AXS1-UP; AXY1-UP)

962G (S/N: BDP1-UP; 3BS1-UP; 5AS1-UP; 5RS1-UP; 4PW1-UP; 6EW1-UP; 6HW1-UP; 7BW1-UP)

962H (S/N: N4A1-UP; M3G1-UP; J6J1-UP; K6K1-UP)

966F (S/N: 4YG1-UP; 3XJ1-UP)

966G Series II (S/N: AXJ1-UP; AXL1-UP; ANT1-UP; AWY1-UP; ANZ1-UP; AWZ1-UP)

966G (S/N: AAH1-UP; 3ZS1-UP; 9RS1-UP; 3PW1-UP; 3SW1-UP; 8XW1-UP)

966H (S/N: A6D1-UP; A6G1-UP; A6J1-UP)

972G Series II (S/N: AXC1-UP; AXE1-UP; AXN1-UP; AXP1-UP; ANY1-UP)

972G (S/N: 7LS1-UP; AAW1-UP; 1EW1-UP; 4WW1-UP; 6AW1-UP; 9GW1-UP)

972H (S/N: A7D1-UP; A7G1-UP; A7J1-UP)

980G Series II (S/N: AXG1-UP; AWH1-UP; AYT1-UP)

980G (S/N: 9CM1-UP; 2KR1-UP; 2SR1-UP)

980H (S/N: MHG1-UP; A8J1-UP; JMS1-UP)

988G (S/N: BNH1-UP; 2TW1-UP)

988H (S/N: BXY1-UP)

990 Series II (S/N: BCR1-UP; 4FR1-UP)

990H (S/N: BWX1-UP)

992C (S/N: 42X1-UP; 49Z1-UP)

992G (S/N: 7HR1-UP; ADZ1-UP)

Wheel Loader:

950B (S/N: 22Z1-UP; 4DJ1-UP; 99Y1-UP; 8BG1-UP)

Introduction

ReferenceOperation Manual, SEBU7012, "Payload Control System"

ReferenceSystems Operations, Troubleshooting, and Testing and Adjusting, SENR6614, "Payload Control System"

Due to a significant amount of content (software) change, the release of Payload Control System (PCS) 2.09 has necessitated the update of Operation Manual, SEBU7012, "Payload Control System" and Systems Operations, Troubleshooting, and Testing and Adjusting, SENR6614, "Payload Control System". The intent of this document is to bridge the information gap between the release of PCS 2.09 and the next updates of Operation Manual, SEBU7012, "Payload Control System" and Systems Operations, Troubleshooting, and Testing and Adjusting, SENR6614, "Payload Control System". For clarification, updated paragraphs from Operation Manual, SEBU7012, "Payload Control System" and Systems Operations, Troubleshooting, and Testing and Adjusting, SENR6614, "Payload Control System" have been included in this document.

The material in this document will help Owners, Operators, Service Technicians, and Technical Coordinators extract the maximum benefit out of PCS.

Functional Changes

The latest version of PCS software contains improvements that were designed to help the operator achieve the best possible payload accuracy under the widest variety of operating conditions. This does not mean that PCS can achieve high levels of accuracy under all operating conditions. The behavior of the operator will still have a significant impact on the accuracy of the payload system.

The software changes that have been incorporated into the PCS can be divided into three categories: Accuracy Improvement Algorithms, Lift Check Algorithms and Convenience Changes.

Accuracy Improvement Algorithms

Accuracy Improvement Algorithms are additional activities that are performed by the software. Accuracy Improvement Algorithms will improve the accuracy and repeatability of the software.

Accuracy Improvement Algorithms include:

• Data Smoothing Techniques that make the software less prone to errors associated with machine motion.

• A Temperature Compensation Strategy that makes the software less prone to errors associated with changes in Hydraulic Oil Temperature.

• A better Lift Velocity Compensation Methodology.

• A Re-zeroing Reminder that periodically reminds the operator to re-zero the bucket.

Lift Check Algorithms

Lift Check Algorithms monitor the lift for activities that can yield poor results. When activities that yield poor results are found, the operator is notified that a reweigh might be appropriate.

Lift Check Algorithms include:

• Lift Velocity Checks that flag the operator when the lift speed changes too much during the weigh cycle.

• Noise Checks that identify lifts that are too noisy for PCS to extract a valid weight.

Convenience Changes

Convenience changes make the PCS easier to use. Convenience changes do not change the accuracy of the PCS.

Convenience Changes include:

• A Velocity Calibration routine that takes significantly less time to complete.

• A convenient method for selecting between one and two digits of precision in the owner's menu.

Menu Changes

Note: Factory Default Settings for each Menu item are followed by an asterisk (*).

Illustration 1	g00989132
PCS Menu Structure

Re-Zero (Re-Zero On*/Re-Zero Off)

When the Re-Zero Reminder is activated, the PCS contains software that will periodically remind the operator to Re-Zero the bucket. This reminder advises the operator when it is appropriate to Re-Zero but does not require the operator to comply. If the notice comes at an inopportune time (the operator is in the middle of loading a truck), the reminder can be snoozed for two minutes by pressing the clear key. After two minutes, the reminder will reappear. Every time the reminder appears, the reminder must be either snoozed (for two minutes) or the bucket must be Re-Zeroed. The default setting for this feature is "Re-Zero On".

When the machine starts up, the Re-Zero reminder will appear fairly frequently (every five minutes). As the machine warms up and stabilizes, the reminder will appear less frequently (as infrequently as every thirty minutes).

Re-Zeroing the machine regularly will improve accuracy by compensating for machine bias that is associated with pin lubrication, oil temperature, and material carry-back.

Velocity Check (0 - 10* - 65536)

PCS contains software that monitors the lift speed in the weigh range. When the lift speed changes by more than the threshold that has been set in this menu location, PCS software will flag a bad lift. The threshold is in terms of percent/second*10. For example, if the threshold value was set to 20, a lift speed change of 2%/second would be enough to kick out the lift. The default setting for this feature is "10".

Setting this threshold to a high number will make the PCS more tolerant of changes in the lift speed. Setting this threshold to a low number will make PCS less tolerant of changes in the lift speed. Changing the lift speed in the weigh range will adversely affect the payload system's ability to calculate an accurate payload.

The default number provides a good balance between attaining good accuracy and allowing the operator to achieve high productivity. The threshold should be bumped up in small increments if the operator is maintaining a constant lift speed and is still receiving an excessive number of reweighs associated with lift speed.

Note: Moving the threshold up too far can compromise accuracy by giving the operator the capability to perform accuracy-compromising tasks during the weigh range. The most common accuracy-compromising tasks that are performed during the weigh range include moving the lift handle out of detent or changing engine speed.

Start of Lift (None - 5% - 10%* - 15%)

Start of Lift sets the amount of payload data that is gathered prior to the bucket entering the weigh range. The value is set as a percent of full lift travel and is relative to the bottom of the weigh range. The default setting for this feature is "10%".

Example 1 - The lift range is set from 50% to 80%. The Start of Lift is set for 10%. The PCS would begin gathering data at the 40% point.

Example 2 - The lift range is set from 40% to 70%. The Start of Lift is set for 15%. The PCS would begin gathering data at the 25% point.

The PCS maintains the same restrictions in the start of the lift range that is maintains in the weigh range (constant lift speed, modest lift noise, etc.).

The default setting of 10% provides sufficient lead data so that the PCS can obtain an accurate payload reading. Increasing this number to 15% will provide slightly better accuracy but will require the operator to maintain a constant lift speed for a larger part of the lift range. Decreasing the default setting to 5% or None will reduce the lift range where the operator needs to maintain a smooth steady lift but will adversely affect accuracy.

Display Resolution (AUTO* - 1 - 2)

This menu item provides a convenient method for setting the precision level that is provided by the PCS. The default setting for this feature is " AUTO", which maintains the same precision rules that were used in previous versions of PCS.

Setting this menu item to a value of 1 will force the PCS to display one digit of precision (30.2 tons). Setting this menu item to a value of 2 will force the PCS to display two digits of precision (30.23 tons).

Skew Resolution (Low* - Middle - High - None)

The PCS contains software that monitors the lift pressure during the weigh range and flags an error if the pressure bounces around excessively. This could happen under the following conditions:

• If the operator is weighing while travelling over rough terrain.

• If the operator started the lift so aggressively that the machine started bouncing up and down.

This feature will help the operator develop a good lifting technique that maintains loading productivity while still allowing PCS to calculate an accurate payload. The default setting for this feature is "Low". Setting this menu value to Middle, High, or None will make the PCS increasingly tolerant of machine and operator induced noise that can affect payload accuracy.

It is possible for a conscientious operator to get excessive re-weigh notices from Skew because of machine issues. The lift profile of some machines is so erratic that even the best operator can't get past the Low Skew threshold under the best of conditions. Under these circumstances, it is recommended that the Skew Resolution be set to Middle and the PCS re-evaluated. If the PCS continues to flag excessive Re-weighs for Skew after the Skew Resolution has been set to Middle, it can be bumped up to High. However, it would be better to first check the machine for the following problems:

• The validity of the calibration.

• Pin or pin lubrication problems.

• Operator technique.

• Valve and pump problems.

Generally, the Skew should only be set to High or None if accuracy is not an issue.

Temperature Compensation (0* - 65536)

The PCS contains software that compensates the payload for changes in hydraulic oil temperature (such as the machine cooling down after sitting idle for ten minutes). The default setting for this technique is "0" or OFF. This software requires some tuning by the service personnel. But, if the decision is made to use this software, the value can be set to match the machine. Tuning this feature is described later in this document.

Note: This feature is limited to machines equipped with CMS or VIMS.

Start of Lift and Weigh Range Discussion

Illustration 2	g00989102
Sample Lift Ranges

Illustration 2 illustrates several key terms that are used throughout this document. Lift height is described in percentage of a full lift. A bucket at the top of the machine's lift height (with the cylinders fully extended) is said to have a lift height of 100%. A bucket on the ground (with the cylinders fully retracted) is said to have a lift height of 0%.

The default PCS weigh range starts at 50% and ends at 80%. The default Start of Lift value is 10% or 10% before the Start of Weigh. If the Start of Lift setting remains unchanged, the Start of Lift will move up and down with the Start of Weigh. Refer to the examples below:

Example 1 - The Start of Lift would move down to 30% if the Start of Weigh was moved from 50% to 40% and the Start of Lift remained at 10%.

Example 2 - The Start of Lift would move up to 35% if the Start of Weigh remained unchanged and the Start of Lift setting was changed to 15%.

The machine must be lifting at a constant speed in the weigh range to achieve high accuracy. The machine should be fairly close to lifting at a constant speed between the Start of Lift and the Start of Weigh.

Setting the Temperature Compensation

Note: Temperature compensation must be turned on before the machine is calibrated. A good starting number for medium wheel loaders is 12.

Any one of the following methods can be used to determine the optimum temperature compensation coefficient for the machine that is being analyzed.

Method 1

1. Monitor the machine from day to day.

2. Tune the number DOWN when the machine reads too heavy when the machine is cold (early in the morning) or when the machine reads too light when the machine is hot (after loading trucks).

3. Tune the number UP when the machine reads too light when the machine is cold (early in the morning) or when the machine reads too heavy when the machine is hot (after loading trucks).

The optimum number will be found if the coefficient is slowly adjusted over a period of a few weeks.

Method 2

1. Exercise the pins immediately after the machine starts up but don't warm up the hydraulic oil.

2. Load several trucks and compare the PCS weight to the scale weight (in pounds). To set up CMS to report oil temperature (on the screen in Mode 2 - Gage 3), record the hydraulic oil temperature. Oil temperature can be monitored using a 4C-8195 Control Service Tool .

3. Warm up the machine to normal operating temperature and load several more trucks. Record the oil temperature, scale weight, and PCS weight.

4. Calculate the PCS error by subtracting the PCS weight from the scale weight.

5. Calculate the average error by summing the errors and dividing by the number of truckloads.

6. Calculate the average temperature by summing the oil temperature for each lift and dividing by the number of truckloads.

Illustration 3	g00989385
Calculate Average Temperature Formula

Best Practices and Findings

Beyond the improvements in the PCS software, there are habits and activities that the operator can embrace that will significantly impact the likelihood of obtaining an accurate payload.

Operational and Maintenance Recommendations

The list below is the result of extensive study. These suggestions will help the operator work with the payload system in order to achieve the best accuracy available.

1. If the machine has been sitting idle for any period longer than 15 minutes, warm up the hydraulics and exercise the pins before weighing the truck. PCS now compensates for changes in hydraulic oil temperature. However, this does nothing to compensate for the joint stiffening an idle machine will experience. The best practice is to perform ten empty lifts where the bucket is raised to full height from the ground. This will exercise the pins and the lift arms while cycling the hydraulic oil through the lift system.

2. All bucket lifts (Full and Re-Zero) should be performed with the bucket fully racked back. Keeping the bucket fully racked back during lifts ensures that the bucket position is consistent from lift to lift. Bucket position can impact the amount of pressure that is required to lift a given bucket of material. Inconsistent bucket positions can lead to inaccuracies in the payload.

3. Weighing should be performed on a flat level surface. Weighing material with the machine sitting on a slope will affect accuracy by changing the load's center of gravity.

4. Maintain a constant engine speed throughout the weigh range. Changing the lift speed during the weigh range compromises the effectiveness of the lift speed compensation algorithm.

5. Start the lift from the lowest starting point available. This will allow the engine speed and the lift speed to stabilize before entering the weigh range. An additional advantage of this technique is that the machine will exhibit less tire bounce when the bucket enters the weigh range. Therefore, starting the lift from the lowest starting point available will yield better accuracy.

6. Ease the lift lever into the detent position. This will provide a smoother start of lift with less tire bounce. PCS will have more difficulty getting an accurate reading when the machine is bouncing around. Slower lifting will also lead to less machine bounce and better accuracy.

7. Keep the lift lever in the detent position throughout the weigh range. Along with maintaining a constant engine speed, keeping the lift lever in the detent position will provide a smooth stable lift speed in the weigh range.

8. Move the lift height kick-out well beyond the end of the weigh range. This will contribute to maintaining a constant lift speed during the weigh range.

9. Watch for spill-off when loading the truck. For material that is spilled on the ground, the truck scale will not match the PCS weight.

10. If the machine is equipped with Ride Control, set the machine's ride control to Auto or OFF. If Ride Control engages during the weigh range, it will affect the payload results.

11. Enable the Re-Zero reminder in the owner's menu and Re-Zero when prompted by the PCS. PCS should be Re-Zeroed anytime material builds up in the bucket.

12. Comply with PCS Re-Weigh requests. PCS requests a Re-Weigh because the machine has done something that will compromise PCS's ability to achieve high accuracy.

13. Use consistent load sizes when multi-pass loading. To achieve a sum total of 21 tons, it is preferable to have three seven-ton bucket loads rather than two ten-ton bucket loads with a trim load of one ton. PCS has difficulty calculating an accurate payload on very light loads because of system noise.

14. Keep the lift checks (Velocity and Skew) set as tight as possible. Also, keep the start of lift at 10% or 15%.

15. The highest accuracy can be achieved by lifting the bucket while the machine is stationary. Lifting the bucket while the machine is moving adds additional noise components that make it more difficult for PCS to calculate an accurate payload.

16. Configure the machine for a wide weigh range. A 30% weigh range is desirable (40%-70% or 50%-80%). If the top of the lift range needs to be lowered, the bottom of the lift range should also be lowered.

17. Calibrate the machine at the same lift speed that the operator prefers to work. If the operator typically lifts at 1700 RPM, the machine should be calibrated at 1700 RPM. To accommodate multiple operators on a single machine, split the difference between the operators.

    For example, three operators use the same machine. Operator A typically lifts at 1500 RPM. Operator B typically lifts at 2000 RPM. Operator C typically lifts at 2200 RPM. The average engine speed of the three operators is 1900 RPM. Therefore, the machine should be calibrated at 1900 RPM.

18. The machine should be fully warmed up prior to attempting a calibration. Optimally, the machine should be used for production loading for at least an hour before a calibration is attempted. This ensures that the pins are loosened up and the grease is evenly distributed around the pins.

19. Recalibrate the machine after any of the following changes in the weighing system:
    • Bucket change

    • Pin change

    • Cylinder change

    • Lift arm change

    • Pressure sensor change

    • Position sensor change

    • Lift valve change

    • Pump change

    Recalibration should also be performed if the PCS system is moved from one machine to another. Every machine is different and the calibration will vary from machine to machine. This is true even if the machine are of the same type (i.e. 980G).

20. Recalibrate the machine seasonally. In North America, PCS should be calibrated four times a year. Another rule of thumb is to calibrate whenever the ambient temperature changes by 10 °C (18 °F).

21. With respect to Hydraulic Oil and lubrication, adhere to Factory Recommended Maintenance Schedules. Improperly lubricated or damaged pins will bind and catch during the weigh range. This will compromise PCS accuracy.

Error and Warning Messages

LOWER

The "Lower" message appears if the bucket is stopped or if the bucket is travelling down in the weigh range. This message will guide the operator to lower the bucket enough so that an accurate weight can be achieved. PCS will not calculate a weight if the operator attempts to start the lift while the "Lower" message is displayed on the screen.

RE-DO

The "RE-DO" message appears when lift speed is too low. In general, this message only appears during an abnormal lifting condition such as the operator trying to lift at low idle.

When the "RE-DO" message appears, the operator should lower the bucket to a point below the start range and repeat the lift.

REW-1

The "REW-1" message appears if the bucket stops moving during the Start-of-Lift Range or if the bucket stops moving during the Weigh Range. Generally this occurs because the operator does not pull the lever back into detent. The operator then releases the lever before the bucket has traveled completely through the weigh range.

When the "REW-1" message appears, the operator should lower the bucket and then perform a smooth and steady lift. To achieve a smooth and steady lift, the operator must maintain a constant engine speed and keep the lift lever in the detent position. It is also important to press the Reweigh button before performing a Reweigh. If the Reweigh button is not pressed before performing a Reweigh, PCS will count the lift twice. The Reweigh button is located above the "2" on the keypad and is marked "REW".

REW-2

The "REW-2" message appears when machine motion (or bounce) cause pressure spikes that will cause inaccuracies in the payload. The SKEW software identifies excessively noisy lifts and flags these lifts as potential problems. For a discussion of potential pitfalls and appropriate corrective action, refer to a discussion of SKEW in the Menu Section of this Instruction.

When the "REW-2" message appears, the operator should perform the following steps:

1. Lower the bucket to the ground.

2. Press the "REW" key.

3. Hold the engine speed at a constant RPM.

4. Ease the lift handle back into detent.

5. Repeat the lift.

REW-3

The "REW-3" message appears when the lift speed changes by more than the lift speed threshold. This typically occurs because the operator lowered the engine speed during the lift in order to avoid running into the truck. "REW-2" and "REW-3" work together to monitor most errors that occur during the lift range.

When the "REW-3" message appears, the operator should perform the following steps:

1. Lower the bucket to the ground.

2. Press the "REW" key.

3. Hold the engine speed at a constant RPM.

4. Ease the lift handle back into detent.

5. Repeat the lift.

REW-4

The rare "REW-4" error occurs when the travel time through the weigh range is so long that it overruns the memory. PCS can handle a lift that requires as long as six seconds to pass through the weigh range. On a wheel loader, a lift that requires six seconds to pass through the weigh range occurs very infrequently. This error remains for special situations and for debugging purposes.

When the "REW-4" error occurs, the operator should perform the following steps:

1. Lower the bucket to the ground.

2. Press the "REW" key.

3. Hold the engine speed at a constant RPM.

4. Ease the lift handle back into detent.

5. Repeat the lift.

LIFT BUCKET 10 TIMES

After the machine lift system has been idle for more than four hours (the bucket has not passed through the Start-of-Lift or Weigh-Range), this message will appear the first time the bucket enters the Start-of-Lift or Weigh-Range. This message reminds the operator to exercise the linkage after the linkage has been idle.

The preferable action for this reminder is for the operator to pick up ten full buckets of material, lift them to the kick-out, and dump them before returning to weighing activities. This is the best way to distribute grease across the linkage pins and to cycle the hydraulic oil throughout the system.

The second option for this reminder involves lifting a single bucketful of material ten times. This option is less desirable than the first option. The second option does cycle the hydraulic oil and works the grease around the pins.

The third option is to perform ten empty lifts from the ground to kick-out.

The quickest but least recommended option is to press the "Clear" key before returning to weighing activities.

PCS will provide the best results when the hydraulic oil is properly circulated through the system and the pins are properly lubricated.

Re-Zero PCS

This is the automatic reminder to Re-Zero the machine. Re-Zeroing the machine when prompted will reduce errors caused by pressure drift. If the operator is in the middle of loading truck, this message can be snoozed. When this message is snoozed, it will reappear in two minutes. The "Re-Zero PCS" message can be snoozed multiple times but it is recommended that the operator Re-Zero the bucket as soon as possible.

Note: Snooze is accomplished by pressing the "Clear" key while the Re-Zeroing message is scrolling on the screen.

The proper way to Re-Zero is shown in the following steps:

1. Lower the bucket to the ground.

2. Rack the empty bucket back to the stops.

3. Raise the engine speed to the typical lifting speed.

4. Gently pull the lift lever into the detent position.

5. Maintain a constant engine speed throughout the entire lift.

6. When the weight has been displayed, press the "ZERO" key.

The best accuracy will be achieved by performing the Re-Zero lift at the same speed that the operator typically weighs full buckets.

Note: Re-zeroing the machine typically takes six to eight seconds. Re-zeroing the machine is key to achieving high accuracy.

Corrections to Operations Manual, SEBU7012-07, "Payload Control System"

This section is intended to provide clarification and to correct errors found in SEBU7012-07 (August 2001).

Page 8 (Replace Illustration) - Replace the menu found on page eight with the menu found in this Instruction (Illustration 1)

Page 10 (Clarification on Setting the Weigh Range) - It is desirable to have a weigh range of 30% or greater. A weigh range of 30% or greater gives PCS the best opportunity to provide an accurate weight. The top and bottom of the lift range should be kept as far apart as possible while still accommodating the operator's lifting technique.

Page 11 (Clarification on System Calibration) - Replace "If the machine is well maintained and the zero function is used in order to compensate..." with "Calibration should be performed seasonally or any time that average ambient air temperature changes by 10°C".

Page 12 (Correction to Calibrate an Empty Bucket) - Replace "lift an empty bucket at 2000 rpm" with "lift bucket at the operator's normal lifting speed".

Page 12 (Insertion after Calibrate an Empty Bucket in the Stationary Position) - Insert "Calibrate the Full Bucket" which reads as follows: FULL BUCKET LIFTING CALIBRATION - The operator should load the bucket with either a calibration weight or a nearly-full bucket of material if an accurate truck scale is available. The steps are identical to those for an empty bucket (Remember to lift at the operator's typical lifting speed).

It is very important to calibrate the system with a load that is very close to the rated load. PCS will provide a MAX error if a bucket load of material is lifted later that exceeds the calibration weight by 50%. If the message "MAX" appears, dump some material from the bucket and try to lift again. A Recalibration is required if "MAX" repeatedly appears.

Note: If loose material is used, it is very important that no material be lost due to spillage prior to determining its weight. Shake loose material from the bucket prior to beginning this step.

Page 13 (Clarification of Velocity Calibration) - Velocity Calibration in Version 2.09 and 2.09R requires eight lifts from 1000 RPM to 2400 RPM.

Page 13 (Clarification of Entering the weight of the full bucket) - Entering a Cal weight with fractional components requires the operator to hit the decimal key before entering the fractional components. Example: Entering the Cal weight 12.73 would require the following keystrokes [1] [2] [.] [7] [3] [STORE]. The Decimal point button is also the [SERV] button and can be found to the right of the [0] key. This has caused some confusion in the past because it is unlike modern ATMs.

Page 13 (Correction of Zero the Empty Bucket) - Replace "Lift the bucket at 2000 rpm" with "Lift the bucket at the speed the operator typically performs full bucket lifts".

Page 15 (Clarification of Reweigh Mode) - Reweigh Mode is entered by pressing the "REW" key. The operator must enter the Reweigh mode before reweighing the bucket or PCS will count the lift as an additional bucket load.

Note: Stationary Reweigh (lowering the bucket into the Weigh range and waiting for PCS to recalculate the payload) is not recommended when high accuracy is required. The best practice is to lower the bucket below the Start-of-Lift, Press the "Reweigh" key to enter Reweigh mode, and then perform a smooth, stable lift.

Page 15 (Clarification of Excess Mode) - The Excess Mode and Reweigh Mode operate in much the same way. The operator must enter the Excess mode before performing excess weighing. Stationary Excess weighs should not be performed. If Excess mode is being used, the operator should perform a second lift in order to establish the new bucket weight.

Page 15 (Replace the First Paragraph in Zero Function) - The zero function is used to adjust for the changing weight of the bucket pressure bias, pin lubrication, impacted material in the bucket, and machine warm-up issues. Zero should be performed whenever PCS requests a Re-zero and more often if the operator believes the machine has changed in a manner that will affect payload (impacted material has sloughed off, the machine sat idle for ten minutes, the machine was hosed down and experienced rapid cooling, etc.).

Page 15 (Clarification of Zero Function) - The proper method for Re-Zeroing is discussed in the "Error and Warning Message" Section of this document.

Illustration 4	g00990438
Recommended Lift Techniques.

PCS Message Explanation Table