Overview
The DSM modular intelligent electric valve controller uses advanced microprocessor technology, highly integrated ICs and long-life power output devices. It accepts the DC 4–20 mA control signal from the supervisory instrument and the DC 4–20 mA position feedback from the downstream electric actuator (or the potentiometer's "three-wire" signal), and outputs OPEN and CLOSE commands to control and modulate valve opening. It offers digital setting, display, limits, motor-stall protection, wire-break alarm and valve self-calibration, controlling valves, dampers and louvres reliably, stably and precisely — widely applicable in power generation, metallurgy, petroleum and chemicals.
The DSM works not only with single-phase motor actuators (e.g. DKJ and DKZ) but also with three-phase actuators and electric valve gears. Paired with traditional electric valves it multiplies reliability, stability and accuracy several times over — new life for upgrading old actuators.
Main features:
- ● Intelligent calibration: zero and span calibration of valve position and feedback current needs no potentiometer tweaks or reference instruments — press one key at the actual full-close and full-open positions and the unit automatically corrects to 0–100% and DC 4–20 mA over the newly set range.
- ● Digital setting of the valve motor-zone parameters: minimal overshoot, good stability, high control accuracy.
- ● Free opening direction: changing valve action direction or mode requires no rewiring — key setting suffices.
- ● Intelligent step size: avoids hunting or overshoot, improving control accuracy.
- ● Powerful error detection and alarms: on actuator failure the intelligent diagnostics detect, alarm and display the cause, indicating running state exactly. Different faults show different alarms, greatly shortening troubleshooting and restoring service quickly.
- ● Automatic phase protection: field wiring once had to guarantee correct three-phase sequence — wrong phase meant wrong rotation, damaging valve and actuator. Now wiring phase no longer matters: on reversed phases the phase synchroniser corrects automatically, so an OPEN command always drives the preset opening direction regardless of phase order.
- ● Abnormality protections: motor overcurrent — on overcurrent the DSZH220 stops the motor automatically. Transient reversal — when running (say opening) and a close command arrives, internal logic delays a preset time before executing, reducing current shock, extending power-device life and protecting the stem, gearbox and other mechanics from shock loads. Valve jam — if the actuator cannot overcome the valve's starting torque a jam condition exists: after an open/close start command, if the valve does not move within the preset time the internal circuit opens the relevant contacts, forcibly stopping the actuator and raising an alarm, also available via RS-485.
- ● Digital setting of alarm/protection behaviour on signal break.
- ● Non-volatile read-write memory: parameters easy to change, retained through power loss.
- ● Bumpless automatic/manual changeover: good interference immunity.
- ● Simple operation: however complex the functions, the internal software keeps the trouble to itself and gives the convenience to the user — the man-machine dialogue is easy to learn.
(AC 220 V actuators are driven directly; AC 380 V actuators need the AC 380 V power driver unit.)
Technical data
1. Scope of use
- · Actuators: supply 220 V ±15% AC, below 150 W, motors with common/open/close three-wire open-stop-close control;
- · Environment: -20 to 55℃, relative humidity below 90%.
2. Inputs
- · Control input: 4–20 mA DC, input impedance below 150 Ω;
- · Position input: potentiometer, 500 Ω–5 kΩ.
3. Outputs
- · Position feedback: 4–20 mA DC (isolated), load capability below 450 Ω;
- · Switch commands: relay contacts, 5 A at 250 V AC.
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