The WIKA PCA is a mechanical pressure switch with a flameproof enclosure. When the process pressure reaches its preset threshold, the internal microswitch changes state to activate or interrupt an electrical circuit.
Key Features
- Flameproof enclosure: Ex d design for suitable hazardous-area applications.
- Wide setting ranges: From 0.2–1.2 bar up to 200–1,000 bar, with vacuum ranges also available.
- Robust construction: Aluminium alloy or stainless steel enclosure; stainless steel wetted parts as standard.
- Electrical contacts: SPDT or DPDT, with switching capacity up to 250 V AC and 15 A.
- Repeatability: Set-point repeatability of ≤1% of span.
- Safety options: SIL 2- or SIL 3-qualified versions are available for selected configurations.
Suitable Applications
- Chemical and petrochemical plants: Pressure monitoring in demanding process environments.
- Oil and gas facilities: Pressure-dependent control and switching in suitable hazardous areas.
- Power generation: Process pressure monitoring and safety-related switching.
- Water and wastewater systems: Pressure control in compatible process equipment.
- Mining and industrial plants: Reliable switching in harsh environments and confined installation spaces.
Technical Highlights & Selection Considerations
When selecting the PCA, confirm:
- Pressure range: Choose the correct operating and switching range; vacuum versions are also available.
- Sensor element: Diaphragm designs are used for many ranges; piston elements may be used for medium and high ranges, particularly for liquid applications.
- Contact arrangement: Select SPDT for one changeover circuit or DPDT when two separate circuits are required.
- Electrical load: Check voltage, current and contact type. PLC inputs may require optional gold-plated contacts suitable for low switching loads.
- Enclosure and certification: Verify the required Ex d approval, enclosure material and environmental conditions.
- Safety integrity: If used in a safety instrumented function, confirm the exact model's SIL qualification and system requirements.
FAQ
Q1: Does the WIKA PCA require an external power supply?
No separate supply is required for the mechanical switching mechanism to operate. The switch contacts control the connected electrical circuit.
Q2: Is the PCA suitable for hazardous areas?
It has a flameproof Ex d enclosure. Confirm that the specific model's certification matches the hazardous-area classification.
Q3: What is the difference between SPDT and DPDT?
SPDT provides one changeover contact. DPDT provides two changeover contacts, allowing two separate circuits to be switched.
Q4: Can it be connected to a PLC?
Yes, with an appropriate contact configuration. For low-power PLC inputs, confirm whether the optional gold-plated contact version is required.
Q5: What information is needed for a quotation or replacement?
Provide the full model or part number, pressure setting range, required set point, process connection, enclosure material, contact arrangement and required hazardous-area or SIL approvals.
