• Forbes Marshall Private Limited

Smart Positioner

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Forbes Marshall offers a new range of Smart Positioner, Series 8400S. This is a Smart two-wire device that uses a 4-20mA signal input as its set point, deriving its power from the same. It compares the set point with the actual position of the Actuator stem and eliminates the positioning error accurately using an internal PID control action.

The Smart Positioner has variants designed for use in both – safe and hazardous environments respectively. It is a microprocessor based positioner that provides fast, sensitive and accurate positioning for single acting linear pneumatic actuators. It optionally offers HART communication and a 4-20mA output signal as position feedback.

The Smart Positioner 8400SH series uses a unique contactless magnetic position sensing technique in combination with a pair of Hall sensors. This mechanism is free from backlash and friction and helps achieve a fast and accurate position. The position sensing is contactless and achieved by a combination of a shaft-mounted magnet and Hall-effect sensors mounted within the control unit.

Heart of the Smart Positioner is a small piezo based transducer, which is a low power and low air consumption device. The electrical signal from the micro-controller is converted to precise equivalent pneumatic signals through the transducer, which operates the pilot valve, which in turn supplies the proportional air to the valve actuator.

Benefits:

• Precise position control.
• Robust design.
• Auto/Manual Calibration for full stroke.
• Low Air Consumption, which ensures Payback of investment within few months.
• Can be used for Linear, Equal % characteristics irrespective of the Plug characteristics.
• Split Range feature for two valves.
• Alphanumeric LCD display.
• Diagnostic Features.
• Local & Remote Monitoring over HART protocol.
• Can be used for Air to open, Air to close application irrespective of actuator type.
• Magnetic as well as Potentiometric feedback option.
• Basic programming front fascia without configurator.
• Retro-fitting of existing positioner is possible.
• NAMUR tubeless connection for MF-series actuators. Requires less space as external pneumatic tubing is not required

Advantages of HALL based positioner:
• Contact less position feedback system
• Free from backlash
• No wear and tear of hall-feedback parts
• Easy maintenance