DF-98 Electric Proportional Valve Controller

The DF-98 Electric Proportional Valve Controller (electric servo amplifier) uses an integrated operational amplifier and a new anti-misoperation circuit. It adapts to any feedback signal, and both its long-term stability and anti-interference capability have been markedly improved. It is an upgraded replacement for older electric actuator units such as the DF-1. Used together with XMT-79 series and XMT-19 series current-output PID regulators, it converts a DC continuous signal into a relay on/off signal. Used together with JDZ-type linear-stroke electric actuators, it is widely applicable to equipment heated by gas, steam, or fuel for PID regulation of pipeline valve position. It features easy operation, fast response, and high regulating accuracy.

Main Technical Specifications:

1. Input signal:

(1) DC 0~10 mA; input impedance approx. 800Ω  (2) DC 4~20 mA; input impedance approx. 250Ω

(3) DC 0~2.5 V; input impedance approx. 3.6 kΩ (4) DC 1~5 V; input impedance approx. 100 kΩ

2. Output signal: three-position relay output; contact capacity: 250 V / 3 A (resistive load)

3. Feedback signal:

(1) DC 0~10 mA; input impedance approx. 800Ω   (2) DC 4~20 mA; input impedance approx. 250Ω

(3) DC 0~5 V; input impedance approx. 100 kΩ   (4) DC 1~5 V; input impedance approx. 100 kΩ

(5) Feedback potentiometer resistance 1 kΩ

4. Insensitivity: approx. 0.5% of full scale

5. Panel size (W × H): 160×80 mm; 96×96 mm; 72×72 mm

Operation and Adjustment:

1. Wire strictly according to the wiring diagram and verify it is correct; then set the "Manual-Auto" switch to "Manual" and turn on the controller's power switch.

2. Press the "Manual - Close" button; the valve-position pointer on the controller panel should gradually move toward the start, and the valve should gradually close. When the valve is fully closed, the pointer should indicate 0%. Press the "Manual - Open" button to open the valve; when fully open, the pointer should indicate full scale (100%). If it does not reach 100%, adjust the valve-position feedback potentiometer on the regulating valve.

3. Set the "Manual-Auto" switch to "Auto" and apply a DC signal of 0~10 mA etc. matching the specification to the instrument input. As the DC signal gradually increases, the green lamp lights and the valve gradually opens, with the valve-position pointer moving toward full scale. If the wiring is correct but the valve closes as the input increases, swap the two "Open/Close" leads of the valve motor. If other conditions are normal but the valve-position pointer stays below 0%, simply swap the two ends of the valve-position feedback signal lead (do not confuse or misconnect the potentiometer leads for the potentiometer-feedback type).

4. When this controller is used with an XMT-79 series PID regulator, set the "Manual-Auto" switch to "Auto" so that the regulator's output is on (i.e., the measured value is far below the set value); the valve should then be fully open, the pointer should indicate 100%, and the red lamp should go out. If the valve is not fully open (i.e., the motor stroke is not at about 25 mm), adjust the controller's "Feedback" potentiometer until the valve is fully open, the pointer indicates 100%, and the red lamp goes out.

5. When a PID DC signal is input to this controller, PID action can be observed on the valve-position indicator. If it stays fully open (green lamp always on), the feedback voltage may be too small or absent; if it stays fully closed (red lamp always on), the feedback voltage may be too large. Check whether the system interface signals match.

6. When putting the controller into service, generally adjust in "Manual" first, and switch to "Auto" when the measured value reaches about 90% of the set value; this causes less system disturbance and stabilizes faster.

In "Manual" state, if both the "Open" and "Close" buttons are pressed, that is an operation error, and only the button pressed earlier takes effect.

7. If the controller's output action is too frequent, reduce the secondary instrument's derivative time until it is zero.