The Siemens SIPART PS2 is one of the most widely used smart electro-pneumatic valve positioners in thermal power, petrochemical and metallurgical plants. Controlling the pneumatic actuator through piezo valves, it offers extremely low air consumption, high control accuracy and non-contact position detection, supports the HART protocol, and allows remote configuration and diagnostics. This article compiles the PS2's main specifications, two-wire wiring, the complete initialization/commissioning procedure for linear and part-turn actuators, and field troubleshooting of common faults.

Main Specifications

• Input signal: 4–20 mA DC (two-wire)
• Air supply pressure: 1.4–7 bar
• Ingress protection: IP66 / IP67
• Explosion protection: Ex ia IIC T6 / Ex d IIC T6
• Stroke range: linear 10–150 mm; part-turn 0–90°
• Air consumption: extremely low (piezo-valve technology, near zero at standby)

Wiring

The SIPART PS2 uses two-wire wiring: the working power is taken from the 4–20 mA input loop, so no separate supply is needed. Terminals are located in the connection box at the bottom of the housing:

Note: terminal voltage is about 9 V DC — never apply 24 V DC directly to the positioner terminals. HART communication is superimposed on the 4–20 mA loop and accessed via the HART connector.

Commissioning Procedure

Auto-initialization for linear actuators

• Enter configuration: press and hold the mode (configuration) key for more than 5 s; parameter 1 appears
• Actuator type: parameter 1 (YFCT) — select "linear" for linear actuators, "turn" for part-turn
• Rotation angle: parameter 2 (YAGL) — select 33° or 90° to match the travel ratio switch. For linear strokes ≤ 25 mm choose 33°; for > 25 mm or part-turn choose 90°
• Stem range: parameter 3 (YSLP) — select stroke length; select OFF for part-turn; for linear strokes choose the next size up (e.g. 17 mm → 20.0)
• Start initialization: parameter 4 (YINIT) shows "no"; hold "+" for more than 5 s to start
• Wait for completion: RUN1 through RUN5 appear in sequence, taking about 15 minutes; do not press any key
• Exit configuration: when initialization completes, hold the mode key for 5 s to exit into operation

Auto-initialization for part-turn actuators

• Preparation: set the lever ratio switch to 90°
• Installation: mount the positioner, connect pneumatic tubing, air supply and current signal source
• Enter configuration: hold the mode key for more than 5 s
• Select "turn": use "-" to set parameter 1 (YFCT) to "turn"
• Confirm angle: short-press the mode key to reach parameter 2, set automatically to 90°
• Start initialization: hold "+" for more than 5 s; RUN1–RUN5 appear in sequence
• Exit: when complete the full rotation angle is displayed (e.g. 93.5°); hold the mode key for 5 s to exit

Manual initialization (when full stroke cannot be driven)

• Enter configuration as for auto-initialization, switch parameter 4 to parameter 5 (manual initialization mode)
• After holding "+" for 5 s, the first position setpoint appears
• Drive the actuator to the first end position with "+" and "-", confirm with a short press of the programming key
• Drive to the second end position and confirm the same way
• The remaining steps (control-parameter optimization) run automatically; RUN1–RUN5 appear in sequence

Factory reset

If modified parameters prevent initialization, restore factory settings: go to parameter 51 (PRST) and hold "+" for 5 s; a restore symbol confirms success.

Common Faults and Remedies

Related reading: Smart Valve Positioners — Universal Commissioning Workflow & Cross-Brand Troubleshooting