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

Specifications

Technical data
Measuring quantity	Standard flow velocity w_N, based on standard conditions ¹⁾
Measured medium	Clean a orr, nitrogen, additional gases on request
Measuring range w_N	(±)0 … 1 / 2.5 / 10 m/s (uni- or bidirectional)
Max. display range w_N	+10 % above measuring range
Lower detection limit w_N	(±)0.05 m/s
Measuring accuracy
Standard w_N	±(3 % of measured value + 0.05 m/s) ²⁾
High precision (optional) w_N	±(1 % of measured value + 0.04 m/s) ²⁾
Response time (t₉₀) w_N	1 s (configurable: 0.01 ... 10 s)
Operating temperature
Sensor	0 … +60 °C
Storage temperature	-20 … +85 °C
Material
Sensor head	Stainless steel 1.4404
Sensor tube	Stainless steel 1.4404
Plug connector, nut screw	Stainless steel 1.4404
Light ring	PC
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 output w_N	0 … 10 V (R_L > 10 kΩ; C_L ≤ 10 nF; short-circuit protected) 4 … 20 mA (R_L < 300 Ω; C_L ≤ 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)

¹⁾ Standard conditions: T_N = 20 °C and p_N = 1,013.25 hPa

²⁾ Related to adjustment reference; "fmr" = final measuring range

Subject to technical changes.

Order information

	Description	Article-Number
Basic sensor	SCHMIDT^® Flow Sensor SS 20.415 LED	551 490 -	A	1	C	D	E	F	G	H	I
	Options
Mechanical type	Sensor length angled: 150 mm x 300 mm		3
	Sensor length angled: 270 mm x 300 mm		1
	Sensor length straight: 300 mm		2
	Straight, special length: _____ mm	Length: 310 … 1,000 mm (10 mm steps)		9
Protection	Without protective coating			1
Mechanical fixing	Threaded bush M25 with counternut				1
	Threaded bushing M25 with thread adapter M25 x 1.5 to PG21				2
	Threaded bushing M25 with shank nut				3
	Welding bushing				4
	Flange bushing				5
	Without fixation material				6
Measuring range	Measuring rang 0 … 1 m/s					1
	Measuring range 0 … 1 m/s, unidirectional, with option LF indication of threshold monitoring (0.45 m/s ± 20 %)					4
	Measuring range 0 … 2.5 m/s					2
	Measuring range 0 … 10 m/s					3
Measurement direction	Unidirectional						1
Measurement direction	Bidirectional						2
Representation of direction	Unidirectional							1
	Switching output OC 1 = direction signal (only bidirectional)							2
	Zero flow corresponds with halved analog signal (only bidirectional)	0 m/s = 8 mA / 5 V output signal							3
Output signals	0 … 10 V								1
Output signals	4 … 20 mA								2
Adjustment accuracy and calibration	Standard adjustment without certificate									1
	Standard adjustment unidirectional with factory calibration certificate									4
	Standard adjustment bidirectional with factory calibration certificate									5
	High precision adjustment with. factory calibration certificate									2
	High precision adjustment with factory calibration certificate, bidirectional									3
Sensor programming	Factory setting										1
Sensor programming	Customer-specific programming of switching polarity, threshold value, splitting signal, response time										2

Accessories

Connection technology

Description	Article-Number
Coupler socket, 7-pin with soldering sleeves for cable Ø 0.14 mm²	535 278
Connection cable with coupler socket, 7-pin, 5 m length, open cable ends, material PUR	535 279
Connection cable with coupler socket, 7-pin, length selectable (2 … 100 m; 1 m steps), open cable ends	505 911 - 4
Connection cable with angled socket, 7-pin, 10 m length, open cable ends, material PUR	535 281
Power supply unit: output 24 V / 1A DC, supply voltage 115/230 V AC (strip terminal)	535 282

Mounting and fixing technology

Description	Article-Number
Assembly kit for pipe assembly suitable for MD 10.010/10.015 including pipe clamps and collar for adjustment to pipe diameter	531 394

Measured value display

Description	Article-Number
LED display MD 10.010 in wall housing to show volume flow and flow velocity, 85 … 250 V AC and sensor power supply	527 320
LED display MD 10.010, similar to 527 320 but with 24 V DC voltage supply	528 240
LED display MD 10.015, similar to 527 320 but with additional sum function and second measuring input	527 330
LED display MD 10.015, similar to 527 330 but with 24 V DC voltage supply	528 250

Miscellaneous