SCHMIDT® Flow Sensor SS 20.420

Thermal flow sensor for unidirectional or bidirectional measurement of flow velocity of air with simultaneous detection of flow direction.

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
Measuring range w_N	(±)0 … 1 / 2.5 / 5 / 10 m/s
Lower detection limit w_N	(±)0.05 m/s
Measuring accuracy
Standard w_N	±(5 % of measured value + [1 % of fmr; min. 0.05 m/s]) ²⁾
High precision (optional) w_N	±(3 % of measured value + [1 % of fmr; min. 0.05 m/s]) ²⁾
Response time (t₉₀) w_N	0.2 s
Operating temperature
Sensor	0 … +60 °C
Storage temperature	-20 … +85 °C
General data
Humidity	Measuring mode: Non-condensing (< 95 % RH)
Operating pressure (max.)	Atmospheric (700 … 1,300 hPa)
Supply voltage	12 … 26.4 V DC
Current consumption	Typ. < 6 mA (max. 10 mA)
Analog output	0 … 10 V (R_L ≥ 10 kΩ; C_L ≤ 1 nF; short-circuit protected)
Electrical connection	Non-detachable cable, 3 wires, length 5 m, with ferrules
Maximum cable length	15 m
Mounting position	±3° relative to flow direction
Protection type	III (SELV or PELV)
Protection class	IP65
Probe length	60/110 mm (order option)
Weight	Approx. 40 g (sensor llength of 110 mm)
Material
Sensor head	Ø 9 mm x 10 mm stainless steel 1.4404
Sensor tube	Ø 9 mm stainless steel 1.4404
Cable sheath	PVC

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

	Description	Article Number
Basic sensor	SCHMIDT^® Flow Sensor SS 20.420 basic version: w_N; cable 5 m; output signal: 0 … 10 V	538 045 -	A	1	C	D	E	F
	Options
Sensor type	Standard		1
Mechanical type	Sensor length 60 mm			1
Mechanical type	Sensor length 110 mm			2
Measuring range	Measuring range 0 … 1 m/s				1
	Measuring range 0 … 2.5 m/s				2
	Measuring range 0 … 5 m/s				3
	Measuring range 0 … 10 m/s				4
Measurement direction, setting and adjustment	Unidirectional – standard adjustment (5-%-class)					1
	Unidirectional – standard adjustment with factory calibration certificate (5-%-class)				5
	Bidirectional – standard adjustment (5-%-class), representation of direction with halved analog signal: 0 m/s = 5 V output signal (analog output 50 %)					2
	Bidirectional – standard adjustment with factory calibration certificate (5-%-class), representation of direction with halved analog signal: 0 m/s = 5 V output signal (analog output 50 %)					6
	Unidirectional – high precision adjustment with factory calibration certificate (3-%-class)					3
	Bidirectional – high precision adjustment with factory calibration certificate (3-%-class), representation of direction with halved analog signal: 0 m/s = 5 V output signal (analog output 50 %)					4
Analog output	0 … 10 V						1
Connection cable	5 m cable with open ends							1

Connection technology

Description	Article-Number
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
Wall mounting bracket, aluminium anodized	503 895
Mounting flange, stainless steel 1.4404	551 740
Compresson fitting, stainless steel, G½, atmospheric pressure	532 160
Welding sleeve, stainless steel 1.4571, G½, according to EN 10241, 2 pieces	524 882
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 the wall housing to visualize the volumetric flow and the flow velocity (or other measures), 85…250 V AC and sensor supply	527 320
SCHMIDT® LED display MD 10.010; as with 527 320 but with 24 V DC voltage supply	528 240
SCHMIDT® LED display MD 10.015; in the wall housing to visualize the volumetric flow and the flow velocity (or other measures), with additional sum function and second measuring input, 85 … 250 V AC and sensor supply	527 330
SCHMIDT® LED display MD 10.015; as with 527 330 but with 24 V DC voltage supply	528 250