SIPART PS2 Positioner 6DR5 Series - 6DR5125-0EG00-0AA0   

The SIPART PS2 positioner uses a closed-loop feedback system to control a pneumatic actuator. It receives a setpoint signal (often a 4 to 20 mA current loop) and compares it to the actual valve position, measured by a sensor. Based on this comparison, it adjusts compressed air supply to the actuator using a high-speed piezoelectric valve, moving the valve to the correct position and maintaining it with low air consumption in its stationary mode.

Working principle 

1. Receive control signal: The positioner receives a control signal (e.g., 4-20 mA) from a higher-level control system like a PLC or DCS.
2. Compare and act: It compares the received setpoint with the actual valve position, which is measured by an internal or external sensor.
3. Control air supply:

• Based on the difference, the positioner sends a signal to a pisel valve.
• The pisel valve modulates compressed air to the pneumatic actuator.
• This moves the actuator to a position that matches the setpoint.

4. Minimize air consumption:

• The pisel crystal technology activates the pisel valves only when the actuator needs to move.
• This "pulsed air" design drastically reduces air consumption compared to conventional positioners.

5. Provide feedback:

The positioner can communicate its status, diagnostic information, and valve position back to the control system using protocols like HART, PROFIBUS, or Foundation Fieldbus.
It provides self-diagnostics to detect issues like leaks, stiction, and other performance deviations, which can be used for maintenance planning

Working Principle

The operation of the SIPART PS2 is a closed-loop control process involving electronic control and pneumatic actuation:

1. Setpoint Reception: The positioner receives an electrical setpoint signal (typically 4-20 mA or a digital bus signal like PROFIBUS PA or FOUNDATION Fieldbus) from a control system.
2. Position Sensing: The actual position of the valve's linear or rotary actuator is detected by a high-quality, wear-free position sensor (e.g., a potentiometer via a gear transmission or a non-contacting sensor using the GMR effect). This actual position is fed back to the microcontroller.
3. Microcontroller Processing: The integrated microcontroller continuously compares the setpoint (desired position) with the actual position (feedback value). It calculates the deviation (system deviation) between the two.
4. Pneumatic Control (Piezoelectric Valve): Based on the size and direction of this deviation, the microcontroller sends an electric control command to a highly responsive piezoelectric valve.

• For large deviations, the positioner outputs a continuous signal to quickly move the actuator (high-speed zone).
• For moderate deviations, it outputs a sequence of pulses.
• For small deviations, no positioning signals are output (adaptive or variable dead zone).

5. Actuator Movement: The piezoelectric valve converts the electrical command into a precise pneumatic pressure increment (air flow) and supplies it to the pneumatic actuator. This causes the actuator to move the valve stem or shaft.
6. Continuous Feedback: As the actuator moves, the position sensor provides continuous feedback to the microcontroller, closing the control loop until the actual position matches the setpoint.

Key Features of the Working Principle

• High Efficiency: The use of a pulsed air design via the piezoelectric valve means air is only consumed during the actual movement, resulting in significantly lower air consumption compared to conventional positioners.
• Automatic Commissioning: The device can automatically determine the zero point, full-scale value, positioning speed, and dead zone during a simple initialization process, optimizing its performance for the specific valve/actuator assembly.
• Diagnostics: The integrated microcontroller enables advanced diagnostics, such as monitoring for leaks, stiction, valve seat wear, and performing partial stroke tests (PSTs) on emergency shutdown (ESD) valves, enhancing overall plant safety and preventative maintenance.

 Full Datasheet

Positioner Transmitter Feature  

• Manufacturer: SIPART PS2
• Product No. :  6DR5125-0EG00-0AA0                                                                                                                                                             
• 6DR5 - SIPART PS2 electropneumatic positioner in enclosure made of polycarbonate, aluminum and stainless steel
• Version 1 - With HART, not explosionprotected
• For actuator: 2 -Double-acting
• special number: 5 
• special number: 0E  
• Connection thread electrical/pneumatic: G - M20 x 1.5 / G¼
• Limit monitor: 0 - Without
• Option modules: 0 -  Without
• Brief instructions: A - German/English/Chinese
• Special number:A
• Mounted pressure gauge block: 0 - Without

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

Basic Ordering Information