WOODWARD GOVERNOR SERVICE MANUAL FOR CATERPILLAR G330 Caterpillar

Initial Calibration Settings

The DMMP control's tunable setpoints and their default values follow. Space is provided next to each value to write in the final value for future reference.

Service Headers Initial Settings

Configure Headers Initial Settings

Foot Pedal Calibration

The foot pedal may need to be calibrated if the pedal performance is unacceptable. The foot pedal's position range must match the range set in the DMMP control. And the Idle Validation mode must be enabled or disabled depending on the foot pedal installed.

The foot pedal position sensor is supplied with +5 Vdc (+) and a return (-). The sense (0) signal must be within a range of 0.0 to 5.0 Vdc for the DMMP control to function properly. The foot pedal input is not intended to be used with a PWM (pulse-width-modulated) sense signal.

You can find all of the foot pedal calibration setpoints in the PC Service Tool FOOT PEDAL header.

* Verify the sense voltage at the DMMP control. Watch the foot pedal position while you press the foot pedal. The readout should vary over some range, increasing as the pedal is depressed. The output range of the sensor should be between 50% and 90% for the best operation. If the range is more than 90%, the DMMP control will not be able to accurately detect foot pedal faults. If the range is less than 50%, the foot pedal will not control the actuator position accurately. If the position does not increase as the pedal is depressed, the position sensor is wired wrong and needs to be corrected before preceding.

* Set the minimum foot pedal. The end points of the foot pedal's travel must be set to eliminate all deadband during normal operation. Start by leaving the foot pedal in its idle position. Note the foot pedal position from the PC Service Tool and change the minimum foot pedal value until it is within 1% of the actual readout. Depress the foot pedal a few times to verify the repeatability of the position sensor at the idle position. Set the minimum foot pedal to the lowest noted value. The total deviation should be less than 2%.

* Set the maximum foot pedal. The maximum foot pedal is not as critical as the minimum foot pedal, but it should be close to make sure full actuator travel is achieved. Fully depress the foot pedal and note the position. Go to the maximum foot pedal and change the value until it is within 2% of the fully depressed position.

* Verify that the full travel of the foot pedal moves the actuator through its range of travel (maximum foot pedal = maximum actuator).

Actuator Calibration

The actuator calibration is the most critical calibration in the DMMP control. The actuator should be installed with a linear linkage or direct coupling to the throttle body. All nonlinear functions are handled in software. The actuator and actuator position feedback wiring are the most likely cause of an engine overspeed. The polarity of the actuator and position feedback must match for proper operation. Otherwise, the actuator will be driven to either the minimum or maximum stop depending on the wiring error.

You can find all of the actuator calibration setpoints in the PC Service Tool ACTUATOR header.

Auto Calibration Note

This version of software has two calibration options, automatic and manual. The automatic calibration mode sets the minimum and maximum actuator stops when the DMMP control is first powered up. A calibration error value is also calculated and is used to recalibrate the actuator position readout so that it matches the actuator command. The manual mode requires that the actuator stops be set manually via the PC Service Tool.

For either mode, first verify that the actuator and throttle body are installed properly. First, check that the actuator's minimum stop is at the same point as the throttle body's minimum fuel position. The actuator's minimum stop is denoted by the light return spring that returns the actuator to minimum. Next, look at the actuator position readout and verify that the minimum fuel position is around 10%. Then force the actuator to maximum, and the readout should increase to around 90%. The position readout is dependent on the linkage and throttle body setup.

Automatic Mode

Select Automatic mode by tuning the Auto Actuator Calibration listing in the CALIBRATION SELECT configure header to TRUE. When the DMMP control first powers up, the automatic calibration routine will run. The process will take about 0.5 second. During that time the actuator will kick, which will indicate that the minimum stop is calibrated and the calibration error is found. The maximum stop will not be set until the actuator command goes above 90% for 1.0 second during normal operation (that is, full throttle condition). Until that condition is met, the maximum stop is set to 100% plus the calibration error found at power up. The initial minimum and maximum actuator found values in the ACTUATOR MONITOR header should be checked to make sure the values are valid. For most installations, the minimum actuator found will be between 5% and 15% and the maximum actuator found will be 85% to 95% unless the calibration is incomplete. Once the initial calibration is valid, all other results should be the same.

Manual Mode

Select Manual mode by tuning the Auto Actuator Calibration listing in the CALIBRATION SELECT configure header to FALSE. This requires that the actuator stops be set manually during the initial installation. Once these are set, they will not need to be changed.

1. First find the error between the actuator command and the actuator position readout. With the engine off, increase the minimum actuator stop to 25%. The actuator command should read 25% and the actuator position will be around 25%. The difference between the two is the calibration error. This value may be needed to correct the minimum stop setting.

2. Note the actuator position readout at the minimum stop. Go to the minimum actuator and decrease this value until the position readout stops decreasing. Also see Setting the Software Idle Stop below.

3. Force the actuator to its maximum stop and note this position. Go to the maximum actuator and tune this value until it is the same as the position readout.

NOTE: There will be a calibration error between the actuator command and actuator position readout using the manual mode. If the error is too large (5% or more), it may be necessary to correct the minimum and maximum stops accordingly.

Transmission Signal Calibration

The transmission signal output of the DMMP control provides the transmission with a signal that is proportional to the foot pedal position. The transmission signal helps the transmission determine the shift points during operation. The output calibration process involves setting the two end points on a line.

Some transmissions use a current signal rather than a voltage signal, typically a 4 to 20 mA signal. The DMMP control is capable of acting as current driver if the input impedance of the transmission is 249 ohms. To get the transmission signal to 4 mA, set the output voltage to 1.0 Vdc; to get 20 mA, set the output voltage to 5 Vdc. The output will still be displayed in voltage (1 to 5 volts), but the output will also be 4 to 20 mA.

You can find all of the transmission signal calibration setpoints in the PC Service Tool TRANSMISSION SIGNAL header.

* Set the first pair of points on the minimum end. Go to the minimum output value. This is the voltage that the DMMP control will output at the minimum foot pedal position setting. Set this value to the minimum voltage specified by the transmission manufacturer. Next set the minimum foot pedal position (in the TRANSMISSION SIGNAL header). Change this value to the minimum foot pedal position voltage, located in the FOOT PEDAL header.

* Set the second pair of points on the maximum end. Go to the maximum output value. This is the voltage the DMMP control will output at the maximum foot pedal position setting. Set this value to the maximum voltage specified by the transmission manufacturer. Next go to the maximum foot pedal position value (in the TRANSMISSION SIGNAL header) and set it to the maximum foot pedal position voltage, located in the FOOT PEDAL header.

Switch Output Options

Switch outputs 1 and 2 (J2 pins 10 and 2, respectively) are discrete outputs capable of driving relays, lamps, or other devices requiring battery voltage to activate. Some examples include transmission in gear enable, air conditioning shut off, starter shut off, and transmission shift point interface.

There are three modes of operation for the switch outputs. Mode 1 is a speed switch option that uses the engine rpm signal. Mode 2 is a position switch that uses the foot pedal input signal. Mode 3 is a position switch that uses the actuator (throttle) position feedback signal. See Figure 6-1. The switch operation is basically the same for all three modes, but the switch input signal is different for each mode.

The switch outputs can be set independent of each other, that is, one speed switch and one position switch or any other combination. The switches are configured in the SWITCH SELECT configure header. Switch 1 Select and Switch 2 Select determine the operating mode for the switch outputs.

Figure 6-1. Switch Output Modes

Switch Select 1 - Speed Switch - Engine RPMSwitch Select 2 - Position Switch - Foot Pedal PositionSwitch Select 3 - Position Switch - Actuator (Throttle) Position

Switch Operation

The switches use one of three input signals (engine rpm, foot pedal position, or actuator [throttle] position) to operate, but the switch operation remains the same for any input signal. The switch activates or deactivates at the switch points. The switch points are labeled MAKE and BREAK. MAKE refers to the point at which the output pin activates (+battery voltage). BREAK refers to the point at which the output pin deactivates (no signal). The difference between the make and break points is the hysteresis for the switch.

The action of the output pin is determined by the settings of the make and break points. If the make point is greater than or equal to the break point, then the output will remain deactivated until the input signal goes above the make point. When the input signal goes above the make point, the output is activated and remains activated until the input signal goes below the break point. When the signal goes below the break point, the output deactivates and remains deactivated until the input signal goes above the make point. If the break point is greater than the make point, the output will be activated until the input signal goes above the break point. When the signal goes above the break point, the output deactivates and remains deactivated until the input signal goes below the make point. When the input signal goes below the make point, the output activates. See Figure 6-2 for more information.

Figure 6-2. Switch Output Operation

Speed Switch Operation

The speed switch mode uses engine rpm to trigger the switch output. The speed range is from 0 to 3000 rpm. The speed switch mode uses the SPEED SWITCH service header and Speed Switch Make and Break points. See Figure 6-3.

Figure 6-3. Speed Switch Operation

Position Switch Operation - Foot Pedal Position

The foot pedal position mode uses the foot pedal position to trigger the switch output. The position switch range is from 0 to 100%. The foot pedal position mode uses the POSITION SWITCH service header and the Position Switch Make and Break points. See Figure 6-4.

Figure 6-4. Foot Pedal Position Switch Operation

Position Switch Operation - Actuator (Throttle) Position

The actuator position mode uses the actuator (throttle) position to trigger the switch output. The position switch range is from 0 to 100%. The actuator position mode uses the POSITION SWITCH service header and the Position Switch Make and Break points. See Figure 6-5.

Figure 6-5. Actuator Position Switch Operation

Minimum Governor Speed Settings

The DMMP control allows the minimum governor speed reference to vary as engine load varies. Rather than call out a droop percentage and calculation, the DMMP control uses speed references at no load and full load to calculate the speed reference at current operating conditions. This process makes it easier to set the speed references for either positive or negative slopes.

The idle setpoint is the idle speed of the engine at 0% (no load) actuator. The peak idle setpoint is the speed of the engine at 100% (full load) actuator. For operating conditions between 0% and 100% actuator, the speed reference is calculated and then used by the minimum governor to control engine speed at that point.

Maximum Governor Speed Settings

The maximum governor speed setpoints are factory set and should not be changed without the permission of the engine manufacturer.

This section is given as information only, and the high idle and rated setpoints should not be changed. These setpoints are only accessible with the factory PC Service, as required by EPA regulations.

The DMMP control uses two setpoints to calculate the maximum governor speed reference for any load. The high idle setpoint is the maximum engine speed at 0% (no load) actuator. The rated speed setpoint is the maximum engine speed at 100% (full load) actuator. For any operating condition between 0% and 100%, the DMMP control calculates the speed reference and uses it to control the engine at that point.

Pre-Start System Checks

For maximum protection, we strongly recommend that you strictly follow this section for the initial engine start up.

NOTE: The following section assumes that the control has been wired and installed according to the instructions contained in the Digital Min/Max ProAct control hardware manual (Woodward manual number 04125). Also, the application program and tunable parameter files must already be downloaded to the control.

Show/hide table

Failure to properly install and operate the control system could result in possible personal injury or loss of life. A separate overspeed shutdown device (fuel and/or ignition shutdown) should be installed to prevent an overspeed condition.

Contact Inputs

Start PC Service, press <ENTER>, and page down to the PTO GOVERNOR service header. Enter the header and check the following:

PTO Contact

When the PTO (or fast idle contact) is selected, the PTO Contact parameter should be TRUE. When the PTO is not selected, it should toggle to FALSE.

Go to the Foot Pedal header and check the following:

1. Door Interlock Contact

The Door Interlock Contact should be FALSE when the door is open and TRUE when the door is closed.

2. Idle Validation Contact

The Idle Validation Contact should be TRUE when the foot pedal is depressed and FALSE when the pedal is in its relaxed state. Set Idle Validation Enable to FALSE if no contact is used and leave the Idle Validation contact open.

Monitor

Escape to the main service headers and page down through the service headers.

Engine Speed (RPM)

The Engine Speed at this time should read 0.00.

Actuator Command (%)

The Actuator Command at this time should read 5% ± 5%.

Actuator Position (%)

The Actuator Position at this time should read 5% ± 5%. Manually forcing the actuator to the maximum stop should change the display to 95% ± 2.5%. Note: This may cause faults that will need to be cleared at the end of the setup procedure.

Active Faults

Escape to the main service headers and page down to the FAULT LIST service header.

Cycle the power to the control to clear any active faults that may have been caused during the previous setup. Check all of the parameters listed under the FAULTS header for TRUE conditions. The only one that should be TRUE at this time is the Engine Speed Fault. If any other faults are active, investigate and correct the problem(s) before attempting to start the engine. See the Hardware Troubleshooting section in the next chapter for further explanation of each fault condition.

Fault Logger

Escape to the main service headers and page down to the FAULT LOGGER service header.

Clear the faults that were logged during the installation and setup procedure by changing the *Clear Fault Log parameter from *FALSE to *TRUE and then back to *FALSE again.

Starting the Engine

After you have completed the previous section, the control is ready for engine cranking.

NOTE: If possible, the following steps should be checked without the fuel or the ignition turned on, for maximum protection.

Power the DMMP Control

Start PC Service, press <ENTER>, and page down through the service headers.

Enter the Minimum Governor header and monitor the Engine Speed. From another window, monitor Actuator Command. (If desired, you can monitor up to four other parameters in the remaining service windows.)

Verify that the actuator is at its minimum position and that the throttle body is closed when the control is powered and the engine is not running.

Contact Input Initialization

* Deselect the PTO (fast idle) contact (switch contact open).

* Make sure there is no foot pedal input (relaxed pedal and open Idle Validation Switch contact).

* The door must be closed (switch contact closed).

Cranking the Engine

If the DMMP control has been powered for more than 2 seconds, the Fault lamp should be on, indicating a no-speed-signal-input condition.

Several actions will happen upon cranking the engine:

* The Engine Speed will increase. The speed will need to clear the failsafe speed of 75 rpm before the control will allow any actuator movement.

* The Actuator Output will begin to ramp up.

* The ProAct actuator will rotate to some position and continue to slowly ramp the throttle body open.

* The Fault lamp will turn off.

* If the fuel and ignition are on, the engine will start while the actuator (throttle) is ramping open. Otherwise, when the starter is disengaged and the Engine Speed falls back below 75 rpm, the Fault lamp will come on, and the actuator will be forced to the minimum stop.

If the actions listed above are taking place, and the engine has not already been started, turn on the fuel and ignition and start the engine.

See the next chapter on troubleshooting if any discrepancies are noted.

Once the engine starts, wait for the speed to stabilize. The DMMP should be controlling at the minimum speed reference found in the MINIMUM SPEED GOVERNOR service header. The minimum governor dynamics come preset form the factory and should control the engine at an acceptable level. If the engine is unstable, see the next chapter on troubleshooting.

Setting The Software Idle Stop

Allow the engine to reach normal operating temperature.

Auto Calibration Note

The software idle stop cannot be used if the automatic calibration mode is selected.

This procedure can also be used in place of the minimum actuator calibration if the engine stalls when it comes down to idle.

Continue to monitor the Actuator Command signal in the ACTUATOR MONITOR service header. Open another window and page down to the ACTUATOR MONITOR service header. Enter the header and change the parameter *Minimum Actuator to a value 1.0% less than the Actuator Output reading.

NOTE: While adjusting the *Minimum Actuator, the engine speed may change suddenly if the fast rate of modifying the parameter is used. The control will, however, compensate and return the speed to the Minimum Speed Reference setpoint. Using a slower rate while turning the parameter will cause smaller speed excursions.

This adjustment will prevent the throttle body from snapping closed on its bore and causing damage that can make the butterfly valve stick in the bore. It also prevents the butterfly from completely cutting off air flow that can cause engine stalling when returning to idle with the engine still loaded.

Minimum Speed Governor

With the transmission still in neutral and the door closed, slowly depress the foot pedal. The speed should start to increase as soon as the idle validation contact closes (if used).

If the actuator does not respond to the foot pedal movement, leave the engine running and again verify (using PC Service) that the Idle Validation Contact, Door Interlock Contact, and Foot Pedal Position are all functioning and in the correct position. If the problem is not readily apparent, refer to the next chapter on troubleshooting for more information.

Open the door and verify that the engine returns to idle and the foot pedal is disabled.

PTO (Fast Idle) Governor

Enable the PTO (fast idle) contact and verify that the engine speed increases to the speed reference *PTO Setpoint under the PTO GOVERNOR service header. If possible, load and unload the engine and check for stable PTO governor performance. If the speed control is unacceptable, refer to the next chapter on troubleshooting.

Deactivate the PTO (fast idle). There will be a 2.0 second delay before the engine returns to idle speed. The delay time is set in the software and is tunable under the PTO Delay (SEC) in the PTO Governor header.

Maximum Speed Governor

NOTE: Parts of this section may not be applicable without the availability of suitable equipment to load the engine.

With the transmission in drive and the door closed, load the engine with a dynamometer (or stall an automatic transmission if approved by the manufacturer).

Depress the foot pedal slowly to its maximum stop to increase engine speed, to test the maximum speed governor dynamics. This will require manipulation of the dynamometer (by decreasing load), and will not be attainable in the case of a stall test.

When the maximum speed governor is in control, verify stable governor performance. If the speed control is unacceptable, refer to the next chapter on troubleshooting.

Slowly decrease the foot pedal and unload the engine.

Transient Response

Load and then unload the engine, and release the foot pedal rapidly to force the engine to return to the idle speed. There should be minimal speed undershoot. Turn on all of the engine accessories at once. The engine speed should dip slightly before returning to the Minimum Speed Reference. Turn off all the engine accessories. The engine speed should rise slightly and return to the speed reference. If the transient response is unacceptable, refer to the next chapter on troubleshooting.