SCHMIDT® Flow Sensor SS 20.415 LED

Thermal flow sensor for uni- or bidirectional measurement of air and gases with simultaneous detection of flow direction.

SCHMIDT® Flow Sensor SS 20.415 LED

Thermal flow sensor for uni- or bidirectional measurement of air and gases with simultaneous detection of flow direction.

  • Thermopile head (very fast response time)
  • Flow velocity and switching signals
  • Probe length straight version:

- Default: 300 mm

- Special length (option): > 300 … 1,000 mm (step: 10 mm)

  • Probe length of angled version: 150 / 270 mm x 300 mm
  • Measuring ranges 0 … 1 / 2.5 / 10 m/s
  • Bidirectional measurement (optional)
  • Optimized adjustment for LF-applications (optional)
  • Extremely compact (electronics are integrated in probe tube)
  • Sensor element protected against mechanical stress
  • Linear analog output for measured flow velocity
  • Two switching outputs to signal flow direction and threshold
  • Operating status indication and serial number are visible, even when sensor is installed
  • Special version for laminar-flow monitoring in cleanrooms with quick-mounting system for simple installation beneath ceilings or at walls

Option: Monitoring of admissible speed interval (prescribed by official standards) of 0.45 m/s ± 20 % with optical signaling at the sensor (LF status indicator)

  • Laminar flow monitoring in cleanrooms
  • Flow monitoring in pharmaceutical production, semiconductor manufacturing, food production, LCD manufacturing and optical industry
  • Integration into insulators, FFUs and flow boxes

SCHMIDT Technology – Simply a question of better measurement

Technical data

Measuring quantity

Standard flow velocity wN based on standard conditions temperature of medium TM

Measured medium Clean air or nitrogen, additional gases on request
Measuring range wN (±)0 … 1 / 2.5 / 10 m/s (uni- or bidirectional)
Lower detection limit wN (±)0.05 m/s
Max. display range wN +10 % above measuring range
 

Measuring accuracy

Standard wN ±(3 % of measured value + 0.05 m/s)
High precision (optional) wN ±(1 % of measured value + 0.04 m/s)
Response time (t90) wN 1 s (configurable: 0.01 ... 10 s)
 

Operating temperature

Sensor probe 0 … +60 °C
Electronics -20 … +85 °C
 

General data

Humidity Measuring mode: Non-condensing (< 95 % RH)
Operating pressure (max.) Atmospheric (700 … 1,300 hPa)
Supply voltage 24 V DC ± 10 %
Current consumption Typ. 35 mA / max. 150 mA (including all signal output currents)
Analog outputs (wN and TM) 0 … 10 V (RL > 10 kΩ; CL ≤ 10 nF; short-circuit protected)
4 … 20 mA (RL < 300 Ω; CL ≤ 100 nF)
Switching outputs 2 x open collector (at GND), current-limited and short-circuit protected, configurable
-Channel 1 (OC1): Flow direction or threshold value
- Channel 2 (OC2): Threshold value
- External switching voltage / current: Max. 26.4 V DC / 55 mA (typ. 50 mA)
- Hysteresis: 5 % of threshold value (min. ±0.05 m/s)
(<26.4 V DC / 65 mA)
Channel 1 (OC1): direction or threshold value
Channel 2 (OC2): threshold value
Switching hysteresis 5 % of the threshold value, min ± 0.05 m/s
Error signal Only current interface: 2 mA (according to NAMUR NE43)
Electrical connection Plug-in-connector M9, male, 7-pin (shielded), screwed
Maximum cable length Voltage interface: 10 m; current interface: 100 m
Mounting position Straight: ±3° relative to flow direction (uni- or bidirectional)
Angled: Vertical downdraft flow (per design)
Protection type IP65; electrical connector: IP67 (with correctly attached cable)
Protection class III (SELV) or PELV (EN 50178)
Sensor length Angled: 150/270 mm (vertical) x 300 mm (horizontal)
Straight: Standard 300 mm; special length >300 … 1,000 mm
Weight Approx. 200 g (angled design with 270 mm x 300 mm)
 

Material

Sensor head Stainless steel 1.4404
Sensor tube Stainless steel 1.4404
Plug connector, nut screw Stainless steel 1.4404
Light ring PC
 

Dowloads

Product brochure (02/2024) Dowload PDF
Instructions for use (551742.02D) Dowload PDF
3D-STP data Dowload PDF
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