METSO - Intelligent valve controller- NDX Series - NDX2512HG-NNON0000

The Metso NDX series intelligent valve controller works by using a microcontroller to continuously read the input signal, valve position, and pressures, then it calculates and outputs a control signal to an I/P converter. The I/P converter adjusts the pressure to a pneumatic relay, which in turn controls the actuator to move the valve to the correct position. This is achieved through a closed-loop system where a contactless sensor continuously measures the valve's position, which is then fed back to the microcontroller to modulate the output until the valve reaches the desired position.

Operating principle

• Measurement: The microcontroller (μC) receives an input signal and continuously measures the valve's position with a contactless sensor, along with supply and actuator pressures, and device temperature.
• Calculation: The microcontroller calculates a control signal for an I/P (current-to-pressure) converter based on the input signal and the current valve position.
• Signal transmission: The I/P converter converts this electrical signal into a pneumatic pressure, which controls the pneumatic relay.
• Actuation: The pneumatic relay directs the pneumatic pressure to either apply force to the actuator to move the valve or to vent pressure to the atmosphere.
• Feedback loop: The contactless position sensor continuously sends the valve's actual position back to the microcontroller, allowing it to adjust the control signal to the I/P converter and the valve to achieve and maintain the desired position with precision.

Key features

• Local and remote configuration: The device can be configured and operated both with a local user interface and remotely via a PC with asset management software.
• Diagnostics: It has advanced self-diagnostics to ensure measurements are operating correctly and provides performance and communication diagnostics for maintenance.
• Energy efficiency: The design can achieve significant energy savings by reducing air consumption by up to 90% compared to other solutions.
• Versatility: The controller is designed for use with a wide variety of control valves, including rotary and linear, single and double-acting types.

The Neles (formerly Metso) NDX Series intelligent valve controller works by using a powerful microcontroller to compare a desired input signal (typically 4–20 mA) with the actual position of the valve, then modulating the air pressure to the actuator until the positions match. This creates a precise closed-loop control system.

Operating Principle

The process involves several key components working in unison:

1. Input Signal Processing: The device receives an electrical input signal (e.g., a 4–20 mA loop-powered signal) which represents the desired valve position set by a control system (DCS or PLC).
2. Position Feedback: A contactless position sensor continuously measures the actual physical position (linear or rotary) of the valve stem or shaft.
3. Microcontroller (µC) and Control Algorithm: A powerful internal microcontroller uses a control algorithm (PID control) to compare the input signal (setpoint) with the feedback signal (actual position).
4. I/P Converter: Based on the microcontroller's calculation, a control signal is sent to an I/P (current-to-pressure) converter. This component converts the electrical control signal into a proportional pneumatic pressure signal.
5. Pneumatic Relay: The I/P converter controls the operating pressure to a pneumatic relay (output stage). The relay then uses the supply air to rapidly increase or decrease the pressure to the valve actuator.
6. Actuator and Valve Movement: The changing air pressure moves the actuator, which in turn moves the attached control valve to the required position. The valve movement is continuously monitored by the position sensor, closing the feedback loop.

Key Features Related to the Principle

• Closed-Loop Control: The continuous feedback and adjustment ensure high accuracy and stable control performance.
• Advanced Diagnostics: The internal intelligence of the NDX allows for advanced self-diagnostics, providing data on valve operation, air consumption, and performance, which aids in predictive maintenance.
• Versatility: The same controller unit can be used for both linear and rotary, single-acting and double-acting valves, adapting to various actuator types through configuration.
• Low Air Consumption: The design of the pneumatic relay is highly efficient, reducing energy consumption and operational costs.

More detailed information and resources can be found in the product manuals available from suppliers like Valmet or through distributors.

 Full Datasheet

Positioner Transmitter Feature  

• Manufacturer: Metso - NDX Series
• Product No. : NDX2512HG-NNON0000                
• PRODUCT GROUP - NDX - Intelligent Valve Controller Series NDX Compact Model
• PNEUMATIC ACTION: 2 -  Double Acting (suitable also for single acting actuators)
• PNEUMATIC CAPACITY : 5 - Normal capacity (80 Nm³/h)
• FAIL ACTION: 1 -  Fail safe
• ENCLOSURE: 2 - Flameproof / Explosion Proof - Epoxy coated anodized aluminum housing and cover
• COMMUNICATION / INPUT SIGNAL RANGE: H - 4-20 mA with HART communication
• TEMPERATURE RANGE: G -  General: -40 ... +85 °C / -40 ... +185 °F
• APPROVALS FOR HAZARDOUS AREAS 1: N - No approval
• APPROVALS FOR HAZARDOUS AREAS 2: N -  No approval
• PNEUMATIC CONNECTIONS & GAUGES: 0 -  Standard, 1/4 NPT, no gauges
• VARIANT: N -  Neles
• DIAGNOSTICS: 0 -  Advanced diagnostics Not applicable to 6. sign. “F”
• RESERVED: 0 -  None
• RESERVED: 0 -  None
• RESERVED: 0 -  None

There are several Model of positioner, for more details read the PDF below

Basic Ordering Information 

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