Thermal flow switch FS213

for gasfor waterfor air

Principle and structure: The sealed probe contains two resistors based on the thermal detection principle. One resistor is heated (detection resistor) and the other serves as an unheated reference. When the medium flows, heat is removed from the heated resistor, changing its resistance; the difference between the two resistances is used to determine flow rate.

Key features:

• No moving parts — maintenance-free
• Thermal dual-resistor probe for reliable detection
• Continuously adjustable switching setpoint (potentiometer)
• Dual-use for liquids and gases
• Very low pressure loss; compact stainless steel construction
• 6-LED display for flow trend and switch status
• M12 socket connector; IP67 protection

Applications: Suitable for pneumatic and hydraulic systems, circulating water, cutting fluid and lubricant oil flow monitoring, and pump idling protection. Dual-use design covers both liquid and gas monitoring needs.

Technical specifications:

• Model: FS213
• Measurement ranges: Water 1–150 cm/s; Oil 3–300 cm/s; Gas 20–2000 cm/s
• Initialization time: ≈8 s
• Power supply: 24V ±20% DC
• Signal outputs: PNP, NPN, Relay (NO + NC)
• Electrical protection: reverse polarity, short circuit and overload protection
• Turn-on current: Max 400 mA (PNP/NPN); Max 1 A @24V (Relay)
• No-load current: Max 80 mA
• Response time: 1–13 s (typical 2 s)
• Protection level: IP67
• Connection: M12 socket connector
• Proof pressure: 100 bar
• Materials: Probe and housing — stainless steel
• Medium/ambient/storage temperature: -20 to 80 °C
• Medium temperature change: ≤ 4 °C/s
• Setting type: Potentiometer
• Flow indication: 6-LED display
• Weight: ≈0.4 kg