Programming ECM Governor Gain Parameters{1901, 1908} Caterpillar

Engine:

3508B (S/N: 2BM123-UP; 3DM93-UP; 4GM212-UP; 7SM77-UP; 6PN285-UP; 1TW1-UP; 2HW1-UP; 3DW1-UP; 1FZ1-UP)

3512B (S/N: 7HM172-UP; 8EM258-UP; 8RM200-UP; 4TN96-UP; 6WN135-UP; 1PW1-UP; 2GW1-UP; 4AW1-UP; 1GZ1-UP)

3516B (S/N: 6HN156-UP; 7RN463-UP; 8CN144-UP; 8KN143-UP; 9AN121-UP; 1NW1-UP; 2FW1-UP; 3CW1-UP; 1HZ1-UP)

Introduction

The Governor Gain Parameters are for the 3500B engines that are listed above. The procedure is for all 3500B engines with Version D electronics.

The governor gain parameters are set at the factory. The factory default setting is recommended for most applications. The default settings should allow the engine to respond quickly to transient load changes. The default settings should allow the engine to remain stable during all operating conditions. If the factory default setting does not provide satisfactory performance, the governor gain parameters can be adjusted.

The parameters in table 1 can be adjusted.

Note: No engineering units are associated with the numbers in table 1.

Note: The range of the programmable setting is wide for flexibility. Do not expect to use the whole range. If the programmable setting is greater than the valid range, the system will revert to the factory default value.

Do not perform any procedure in the Special Instruction until you read this information and you understand this information.

Gain Explanations

Governor Gain Factor

The Governor Gain Factor is multiplied by the engine speed error. This value is derived by calculating the difference between the desired speed and the actual speed.

• If the Governor Gain Factor value is too large, the engine speed can overshoot the desired speed.

• If the Governor Gain Factor value is too small, the engine will accelerate slowly.

Governor Minimum/Maximum Stability Factor

The Governor Minimum Stability Factor functions in order to eliminate steady state speed error. The Governor Maximum Stability Factor functions in order to eliminate steady state speed error. The Governor Minimum Stability Factor is used by the ECM when the steady state speed error is less than 20 rpm. The Governor Maximum Stability Factor is used by the ECM when the steady state speed error is increasing and the engine speed error is greater than 20 rpm.

• If the Governor Minimum Stability Factor or the Governor Maximum Stability Factor is set too high, the ECM will provide additional fuel. The additional fuel will cause the engine speed to overshoot. The additional fuel will also cause the engine speed to oscillate.

• If the Governor Minimum Stability Factor or the Governor Maximum Stability Factor is set too low, the engine will not achieve a steady state operation quickly.

Tuning Procedure

1. Turn the ECS to the COOLDOWN/STOP position. Connect the electronic technician. Ensure that engine overspeed protection is enabled before beginning the adjustment procedure. Adjusting Governor Gain Parameters without engine overspeed protection can result in serious engine damage. Ensure that engine overspeed protection is ON. Engine overspeed is configured on the setup screen of Service Monitoring System in electronic technician.

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Personal injury or death can result from engine overspeed. If the engine overspeeds, it can cause injury or parts damage. The engine should be equipped with a separate shutdown device, to protect against engine overspeed. Do not use for emergency shutdown.

2. Start the engine. Observe the control panel to ensure that the engine has reached the rated speed. The control panel will serve as the reference point for engine speed during this procedure.

3. Go to the configuration parameters screen in ET.

   Note: A factory password is required for adjustment of the governor gain parameters. Once the password is entered, the values for the governor gain parameters can be adjusted. If a parameter value that is not a governor gain parameter is altered, a new password will be required. If the configuration parameters screen is stopped during the adjustment of a governor gain parameter, a new factory password will be required.

   Note: Any value may be returned to the factory default setting by typing a number that is greater than the valid range. For example, typing 30,000 will reset a value to the factory default.

4. Set up a field performance test. For example, the engine has poor response during specific load changes.

5. Perform the desired load change from step 4. Observe the response of the engine by viewing the engine speed on the control panel. Observe the engine response by looking at the frequency meter or by listening to the response of the engine.

6. Determine the setting to adjust. Refer to ""Gain Explanations" " and ""Governor Minimum/Maximum Stability Factor" ".

   Note: Usually, the Governor Gain Factor should be somewhat lower than the Governor Minimum Stability Factor for optimum performance. The Governor Maximum Stability Factor is typically a smaller value than the Governor Minimum Stability Factor and Governor Gain Factor.

7. Repeat steps 5, 6, and 7 until a desired engine response can be met. Use large adjustments (10% of original gain) initially for a coarse adjustment to engine response. Use smaller adjustments (1% of total gain) as the engine response is closer to the desired response.