0316453 JOHNSON NEEDLE VALVE, Low speed

An improperly calibrated control could cause an engine overspeed or other damage to the engine. To prevent possible serious injury from an overspeeding engine, read this entire procedure before starting the engine.
Start-up Adjustments
1. Complete the installation checkout procedure in Chapter 3 and the prestart menu settings in Chapter 4.2. Close the Run contact. Open the Failed Speed Override contact. Be sure the Idle/Rated contact is in Idle (Open). Apply power to the control.3. Check the speed sensor.Minimum voltage required from the speed sensor to operate the control is 1.0 Vrms, measured at cranking speed or the lowest controlling speed. For this test, measure the voltage while cranking, with the speed sensor connected to the control. Before cranking, be sure to prevent the engine from starting. At 5% of rated speed and 1.0 Vrms, the failed speed sensing circuit function is cleared.
TO PROTECT AGAINST POSSIBLE PERSONAL INJURY, LOSS OF LIFE, and/or PROPERTY DAMAGE WHEN STARTING THE ENGINE, BE PREPARED TO MAKE AN EMERGENCY SHUTDOWN to protect against runaway or overspeed should the mechanical-hydraulic governor(s), or electric control(s), the actuator(s), fuel control(s), the driving mechanism(s), the linkage(s), or the controlled device(s) fail.
4. Start the engine.If there is insufficient fuel to start the engine, increase the Start Fuel Limit (Menu C). (The control will reduce fuel as required when the speed setting is reached. It requires extra fuel to accelerate the engine to idle speed.) It may take a few starts to determine the final setting of the Start Fuel Limit. If the start time is excessive, increase the Start Fuel Limit. If the start time is too fast or flooding is occurring, decrease the Start Fuel Limit. We recommend trying both hot and cold starts to determine a final setting.5. Adjust for stable operation.If the engine is hunting at a rapid rate, slowly decrease the Gain (Menu A) until performance is stable. If the engine is hunting at a slow rate, increase the Reset time. If increasing the Reset time does not stabilize the engine, it also may be necessary to slowly decrease the Gain OR to slowly decrease the Gain and increase the Compensation.This completes the Start-up adjustments. We recommend saving the settings at this time by pressing the "=" key on the Set Point Programmer.Dynamic Adjustments
The objective of the dynamic adjustments is to obtain the optimum, stable engine speed response from minimum load to full load and speed operating conditions. All adjustments apply to both sets of dynamics, 1 and 2. Use the set point with "1" following when the Alternate Dynamics contact is open and "2" when closed.1. No-Load Adjustments Do this adjustment without load applied.Slowly increase the Gain set point until the engine becomes slightly unstable, then reduce the Gain as necessary to stabilize the engine.After obtaining acceptable performance at no load, record the Actuator Output as read on Menu D. Set the Gain Breakpoint (Menu A) to this reading.2. Minimum Load Adjustment Do this adjustment at the minimum speed and load conditions at which the engine is operated. Be sure to select Rated Speed to switch to the maximum-fuel limit. Speed may be set either with the Raise and Lower commands in local or with a 4 to 20 mA speed reference in remote.Observe the movement of the actuator. If the activity of the actuator is excessive, reduce the Gain set point slightly to get the actuator movement to an acceptable level.If there is a slow periodic cycling of the engine speed above and below the speed setting, there are two possible causes: * Gain is too high and Reset is too low. Reduce the gain by 50% (i.e., if the gain was 0.02, reduce it to 0.01) and increase Reset slightly. Observe the movement of the actuator. Continue to increase Reset until the movement is acceptable but not excessive. A final value of Reset should be between 1.0 and 2.0 for most large engines. If the Reset value exceeds 2.0, but this procedure continues to improve performance, increase the Compensation set point 50% and repeat the procedure.* Gain is too low. If the preceding procedure does not improve the slow periodic cycling of the engine speed, the control may be limiting cycling through the low gain control region set by the Window Width set point. Increase the Gain set point to minimize the cycling. If actuator movement becomes excessive, reduce the Compensation set point until movement is acceptable. In some cases, Compensation may be reduced to zero and only the Gain and Reset adjustments used. This should be done only if necessary to eliminate excessive actuator response to misfiring or other periodic disturbances. Reduce the Window Width set point until the limit cycle amplitude is acceptable without excessive rapid actuator movement.3. Full Load Adjustment Do these adjustments at the speed and load ratings at which the engine is most often operated.If operation in this range is satisfactory, no further dynamic adjustments are necessary. If during changes in speed or load, excessive speed errors occur, increase the Gain Slope adjustment until engine performance is satisfactory. If excessive actuator movement again occurs, do procedure 4, then repeat procedure 3. If the settling time after a speed or load change is too long, reduce the Reset set point slightly and increase the Gain slightly. If slow-speed hunting occurs after a load or speed change but decreases or stops in time, increase the Reset set point slightly and reduce the Gain set point. See Figure 4-4.
The use of negative gain slope should be considered carefully. Low gain at high fuel levels will result in poor load rejection response or possible overspeed. To prevent possible serious injury from an overspeeding engine, the Max Fuel Limit, Menu C, must be set near the full load output current demand to prevent excessive integrator windup and a subsequent low gain condition.
4. When speed and load changes occur, the control should switch automatically to high gain to reduce the amplitude of the offspeeds. Reduce (or increase) the Window Width set point to just