1800IF - PAGE 15 OF 19
Valvcon Corporation
http://www.valvcon.com
phone: 603-249-9020 fax: 603-249-9140
Positioner Board Identification
Controls
1. ZERO - Clockwise adjustment (Minimum Input Signal - set at approximately 50 % for 4-20mA full range
operation)
2. SPAN - Counterclockwise adjustment (Maximum Input Signal- set at approximately 80 % for 4-20 mA full
range operation)
3. NULL - Null Point adjustment
4. LIMIT - Fail Last Position adjustment (set at zero if not using Fail Last Position feature)
LED Indicators
1. "S" and "R" LED's located at the top left corner of the positioner board. These LED's are found only on mA and
0-5 volt units.
"S" - Signal LED. Indicates proper connections and operation of the milliampere signal. The LED illuminates on
application of a 2 milliampere control signal and will increase in brightness as the signal is increased.
"R" - Reversed Polarity LED . When this LED is illuminated and the "S" LED is not illuminated, it indicates that the
signal wire is in the wrong polarity at the terminal strip.
3. RUN - Illuminates each time the positioner requires the actuator to run.
4. CW - Illuminates each time the actuator is powered in the clockwise direction.
5. CCW - Illuminates each time the actuator is powered in the counterclockwise direction.
6. BRK - Illuminates for approximately 1/2 second each time the RUN LED turns off, indicating application of the
electronic braking system to prevent overrunning the new position.
Calibration Procedure
1. Apply the minimum control signal. Adjust the ZERO adjustment until the actuator is in the fully closed, or
desired minimum position. If the RUN and CW LED's are on, back off the ZERO adjustment until both LED's go
off.
2. Apply the maximum control signal. Adjust the SPAN adjustment until the actuator is in the fully open position, or
desired maximum position. If the RUN and CCW LED's are on, back off the SPAN adjustment until both LED's
turn off.
3. Set the NULL adjustment to 70 - 75%. If excessive hunting occurs, decrease this setting in 10% increments
until the hunting stops. Optimum control will occur at the highest setting possible at which no hunting occurs.
