Burkert 323271 (Type 8694) is a compact digital electropneumatic positioner designed for integrated mounting on pneumatically controlled process control valves, such as the ELEMENT Type 23xx and 2103 series. The set-point value setting occurs via a standard 4-20 mA signal or via digital communication interfaces including AS-Interface, IO-Link, or the Bürkert system bus (büS). A contactless sensor element records the valve spindle position, ensuring wear-free operation. Simple start-up is achieved via the automatic X.TUNE function, and basic settings can be configured using the integrated DIP switches.

This positioner features a robust stainless steel and PPS body, making it suitable for demanding industrial environments. The control system consists of two solenoid valves that operate according to the rocker principle, controlled with a PWM voltage to achieve high flexibility regarding actuator volume and final control speed.

Key Features

• Compact and robust design: Stainless steel and PPS construction.
• Start-up with automatic TUNE function: Simplifies commissioning.
• Contact-free position sensor: Ensures wear-free and precise position detection.
• Integrated pilot air duct: Routed directly into the actuator for a clean installation.
• Digital Communication: Available with AS-Interface, IO-Link, or Bürkert system bus (büS).

General Technical Data

Property	Specification
Operating voltage	24 V DC ± 25% (UL: NEC Class 2)
Power consumption	≤ 3.5 W
Protection class	III according to DIN EN 61140
Degree of protection	IP65/IP67 according to EN 60529, 4X according to NEMA 250 Standard
Ambient temperature	-10...+60 °C
Control medium	Neutral gases, air (Quality class according to ISO 8573-1)
Supply pressure	0...7 bar (Low air capacity) / 3...7 bar (High air capacity)
Stroke range (Linear)	3...45 mm
Stroke range (Rotary)	30...180°

X.TUNE Automatic Adjustment

The X.TUNE function must be run for a function check of the positioner to adjust to specific local features. Run X.TUNE whenever the compressed air supply is available during subsequent operation, preferably without operating medium pressure to exclude interference caused by flow forces.

Material Specifications

No.	Element	Material
1	Cover	PC
2	Seal	EPDM
3	Body casing	Stainless steel
4	Seal	EPDM
5	Screws	Stainless steel
6	Push-in connector / Threaded port G 1/8	POM/stainless steel / Stainless steel
7	Basic housing	PPS
8	M12 plug connector	Stainless steel
9	Screws	Stainless steel

Dimensions and Mounting

The positioner is designed for direct mounting on ELEMENT Type 23xx and CLASSIC Type 27xx valve actuators. The mounting position is as required, preferably with the actuator in an upright position.

Electrical Connections

Without fieldbus communication 24 V DC (M12 circular plug, 8-pin)

Pin	Pin assignment
1	Set-point + (0/4...20 mA)
2	Set-point GND
3	Operating voltage GND
4	Operating voltage + 24 V DC
5	Digital input +
6	Digital input GND
7	Analogue position feedback GND
8	Analogue position feedback + (option)

Electrical Safety

Only circuits with limited power may be used for UL approved components according to "NEC Class 2". Before working on equipment or device, switch off the power supply and secure to prevent reactivation.

Signal Flow Diagram

The position measuring system records the current position of the pneumatic actuator. The position controller compares this actual position value with the set-point value. In case of a control deviation, a pulse-width modulated voltage signal is sent to the control system as a manipulated variable to aerate or deaerate the pneumatic actuator until the control difference is zero.

Approvals and Conformities

• Explosion Protection: ATEX II 3D Ex tc IIIC T135 °C Dc / II 3G Ex ec IIC T4 Gc; IECEx Ex tc IIIC T135 °C Dc / Ex ec IIC T4 Gc.
• North America: cULus Listed; FM Explosion Protection (Class I, Zone 2, AEx ec IIC T4 Gc).
• Others: China Compulsory Certification (CCC) for hazardous applications.