Adjust Control Valve

For information about control valves, refer to the Component Overview.

The control valve may need adjustment for specific applications or to fine-tune for best performance. The default values should work for basic operation of the valve.

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Default Valve Settings

Valve Response Rate—Enter value for aggressiveness of the control unit as it approaches target rate. A value that is too high may lead to oscillation, while a value too low may take a long time to reach target rate.

Control Deadband—Enter percent of target rate tolerance for the control valve. For example, if 2% is entered, control unit attempts to adjust flow rate until actual rate is within 2% of target rate.

Valve Delay—Enter amount of time in seconds between when first section is turned on and control unit begins to control flow rate. Valve Delay is useful when starting product application at lower speeds, such as coming out of headland areas.

Valve Advance—Enter amount of time in seconds the control unit commands the control valve to open after all the sections are turned off. Valve Advance may be used with valve delay for low rate applications to build up pressure when the master switch is turned on.

Control Effort—Enter the minimum percentage power needed for the control valve to change position.

PWM (Pulse Width Modulation) Setup Button

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PWM Setup Button

Default PWM Valve Settings

Coil Frequency—Frequency of pulses sent to the PWM valve. PWM coil frequencies synchronize for all products that have PWM valve selected.

(Reference valve manufacturer Operator’s Manual for the recommended settings.)

High Limit—Maximum PWM percent the control unit allows system to reach when product is applying.

Maximum pressure can also be used if a pressure sensor is installed and an alarm is enabled.

Low Limit—Minimum PWM percent the control unit allows system to reach when product is applying.

Minimum pressure can also be used if a pressure sensor is installed and an alarm is enabled.

(Reference Calibrate PWM Limits in Troubleshooting section for more information about setting high and low limits.)

PWM Standby (PWM valve)—When controlling a liquid product, the PWM standby value sets the duty cycle which the system maintains when all sections are closed.

To determine PWM Standby:

1. Fill applicator with product.

2. 
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   A - Test Speed Button

   Select Test Speed button (A) to enter the planned operating speed.

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3. Verify that all sections are closed.

4. Select master switch.

5. 
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   A - Manual Rate Mode

   B - Increase (+) Button

   C - Duty Cycle

   Set the rate selection to manual rate mode (A).

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6. Select Increase (+) button (B) until the system pressure reaches the pressure typically used during field operation.

7. Document the duty cycle (C). Enter the value as the PWM Standby value.

PWM Startup (PWM close valve)—Duty cycle the control unit commands to when valve is opened.

To determine PWM Startup:

1. Fill applicator with product.

2. 
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   A - Test Speed Button

   Select Test Speed button (A) to enter the planned operating speed.

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3. Select the master switch.

4. 
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   A - Specified Rate

   B - Duty Cycle

   Verify that the rate (A) is set to a value typically used during field operation.

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5. Document the duty cycle (B). Enter the value as the PWM Startup value.

Advanced Tuning

Use advanced tuning to more accurately tune the control valve when standard tuning capabilities have been exhausted. After adjusting an advanced tuning value, reset standard tuning settings to default values and retune the control valve.

1. 
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   John Deere Rate Controller 2000 Button

   Select John Deere Rate Controller 2000 button.

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2. 
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   Setup Softkey

   Select Setup softkey.

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3. 
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   A - Settings Tab

   B - Advanced Tuning Button

   Press and hold Settings tab (A) until Advanced Tuning button (B) is displayed.

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4. Select Advanced Tuning button.

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A - Fast Close Valve Kickstart Value

B - P Value

C - I Value

D - D Value

E - S Value

Enter the time in milliseconds for the fast close valve to send the signal ahead of the expected time. Default value is 300 ms.

P, I, D, and S values work together. Adjusting one value may require adjusting other values.

If switching between high and low rates within one product, reduce the P value for low rates.

P Value (B)—Determines how aggressively the system acquires the target rate. Enter a value from 1 through 100.

Higher values: Result in more aggressive rate acquisition.

Lower values: Result in less aggressive rate acquisition.

A non-zero I value is necessary for standard or fast valve systems.

I Value (C)—Determines how aggressively the system responds to the difference between the applied rate and the target rate. Enter a value from 0 through 100.

Higher values: Result in a more aggressive response to rate error.

Lower values: Result in a less aggressive response to rate error.

D Value (D)—Determines how aggressively the system corrects overshooting the target rate. Enter a value from 0 through 100.

Normally this value should be set to a low or zero value. Only increase this value if significant overshoot in target value is seen and reducing the P value has not improved the response.

Higher values: Result in a more aggressive correction to overshooting the target rate.

Lower values: Result in a less aggressive correction to overshooting the target rate.

S Value (E)—Determines the overall system gain. Enter a value from 1 through 100.

Higher values: Increase overall system responsiveness. If too high, the rate oscillates wildly around the target rate.

Lower values: Decrease overall system responsiveness. If too low, the system does not respond to rate adjustments.