SCHMIDT® Flow Sensor SS 20.400

Thermal flow velocity 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 130 … 300 mm
Measuring ranges 0 … 1 m/s to 0 … 20 m/s
Bidirectional measurement (optional)
Detection of flow direction (optional)
Optimized adjustment for LF-applications (optional)
Sensor programming (optional)
Cleanroom sensor
Extremely compact (electronics is integrated in sensor tube)
Sensor element protected against mechanical stress
Linear analog output for measured flow velocity
Two switching outputs to signal flow direction and threshold

Clean rooms and pharma
Laminar flow monitoring in flow boxes
Monitoring of cleanroom overflow
Cooling air monitoring
Flow measurement in test benches

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 air or nitrogen, additional gases on request
Measuring range w_N	(±)0 … 1 / 2.5 / 5 / 10 / 20 m/s (uni- or bidirectional)
Lower detection limit w_N	(±)0.05 m/s
Measuring accuracy
Standard w_N	±(3 % of measured value + [2 % of fmr; min. 0.05 m/s]) ²⁾
High precision (optional) w_N	±(1 % of measured value + [2 % of fmr; min. 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-in connector, nut screw	Stainless steel 1.4404
General data
Humidity	Measuring mode: Non-condensing (< 95 % RH)
Operating pressure	Atmospheric (700 … 1.300 hPa)
Supply voltage	12 … 26.4 V DC
Current consumption	Typical < 35 mA (max. 150 mA, current of switching outputs included)
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)
Electrical connection	Plug-in-connector M9, male, 7-pin (shielded), screwed
Maximum cable length	Voltage interface: 10 m; current interface: 100 m
Mounting position	±3° relative to flow direction (uni- or bidirectional)
Protection type	Sensor probe: IP66; electrical connector: IP67 (with correct attached cable)
Protection class	III (SELV) or PELV (EN 50178)
Sensor length L	130/200/300 mm
Weight	Approx. 60 g max. (L = 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 20.400, thermopile head (also available as: ATEX version (cat. 3G, zone 2; please refer to SS 23.400 ATEX)	518 210 -	X	Y	D	Z	R	-	P
	Options
Mechanical type	Sensor length 130 mm	(only available with 0…10V output signal)		1
	Sensor length 200 mm		2
	Sensor length 300 mm		3
Measurement range	Measurement range 0 … 1 m/s			1
	Measurement range 0 … 2.5 m/s			2
	Measurement range 0 … 5 m/s			3
	Measurement range 0 … 10 m/s			4
	Measurement range 0 … 20 m/s			5
Measurement direction, adjustment accuracy and calibration	Unidirectional – standard adjustment				1
	Unidirectional - default adjustment with factory calibration certificate				6
	Bidirectional – standard adjustment				2
	Bidirectional - default adjustment with factory calibration certificate				7
	Unidirectional – high precision adjustment incl. factory calibration certificate				3
	Bidirectional – high precision adjustment incl. factory calibration certificate				4
	Unidirectional LF - optimized for Laminar Flow application, high precision, with factory calibration certificate (only for measuring range 1 m/s)				5
Analog output	0 … 10 V					1
Analog output	4 … 20 mA (not for sensor length 130 mm)					5
Representation of direction	Bidirectional switching output OC 1						1
	Bidirectional: halved analog signal 0 m/s = 12 mA / 5 V						2
	Unidirectional						3
Sensor-programming	Factory setting								S
Sensor-programming	Customer-specific programming of switching polarity, splitting signal and response time								K

Accessories

Connection technology

Description	Article-Number
Plug-in power supply 24 VDC / 1 A output, 100-240 VAC, 2 m cable length, M12-plug connector (screwed, only usable with "Interface Splitter 4xx")	571630 + splitter
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 open cable ends (length 2 … 100 m; 1-m-steps)	505 911 - 4
Connecting 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
Wall mounting flange, stainless steel, clamping ring PTFE	520 181
Compression fitting, stainless steel, G½, atmospheric pressure	532 160
Wall mounting bracket, aluminium anodized	503 895
Mounting flange, stainless steel 1.4404	551 740
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
SCHMIDT® 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
SCHMIDT® LED display MD 10.010, similar to 527 320 but with 24 V DC voltage supply	528 240
SCHMIDT® LED-display MD 10.015; similar to 527 320 but with additional sum function and second measuring input	527 330
SCHMIDT® LED display MD 10.015, similar to 527 330 but with 24 V DC voltage supply	528 250

Miscellaneous