What is the general threshold for pressure switch action?

Here is the professional English translation of the pressure switch action threshold settings:

⚙️ I. Typical Application Scenarios & Threshold References

Fire Protection Systems‌

Standard Type‌: Activation range ‌0.035–0.05MPa‌ (pump start pressure)

Preaction Systems‌: Lower sensitivity range ‌0.03–0.05MPa‌

Rail Transportation‌

Train braking system trigger point: ‌3.8 Bar‌ (≈ ‌0.38MPa‌), cuts off traction enable when line pressure drops below this value.

Industrial Equipment‌

Reference Point‌: Typically ‌0.5MPa‌ (calibrated at standard atmospheric pressure)

Action Threshold‌: Common setting ‌0.8MPa‌ (adjusted via precision wrench)

Hysteresis Range‌: Maintain ‌0.05–0.2MPa‌ (too small causes frequent cycling; too large reduces accuracy)

🔧 II. Adjustment Procedures

Mechanical Pressure Switches‌

Increasing Threshold‌:

  - Loosen adjustment screw counterclockwise

  - Pressurize to target value

  - Tighten clockwise until contacts activate (audible "click")

Differential Setting‌:

  Lower limit = Upper limit (e.g., 0.8MPa) - Desired differential (e.g., 0.3MPa → 0.5MPa)

Electronic Pressure Switches‌

Modify setpoint via menu interface (long-press function key for calibration mode on some models)

PID algorithm optimization for dynamic conditions

📊 III. Key Parameter Standards

Parameter‌ ‌Recommended Range‌ ‌Application Example‌

Safety Margin‌ ≥1.2× operating pressure Rated 10MPa switch ≤8MPa test

Hysteresis Rate‌ 5%–15% of full scale Food machinery: 5–8%, Industrial: 10–15%

Action Error‌ ≤±1.0% FS 10MPa scale error ≤0.1MPa

️ IV. Critical Prohibitions

Never exceed rated range‌: Test pressure ≤80% of rated value

Avoid insufficient hysteresis‌: Causes equipment cycling → reduced lifespan

Power off before adjustment‌: Always disconnect system power

Post-adjustment Validation‌: Cycle pressure 3×; actuation deviation ≤50% of accuracy class

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