SCHMIDT® Flow Sensor SS 20.651

In many areas the measurement of the flow velocity and / or the volume flow at higher temperatures of up to +350 °C is very important in terms of energy efficiency, quantity detection and plant control.

 

Mechanically rugged, precise and long-term stable measurement values ​​as well as different installation sites

 

  • Drying processes
  • Engine test stands
  • Industrial burners
  • Control of the combustion air

Specifications

Technical Data
Measuring quantityStandard flow velocity wN, based on standard conditions of TN = 20 °C and pN = 1,013.2 hPa
Medium temperature TM
Measured mediumClean air, nitrogen, other gases upon request
Measuring range wN0 … 10 / 20 / 40 / 60 m/s
Lower detection limit wN0.2 m/s (at TM = 20 °C)
Measuring range TM0 … +200 / +350 °C
Measurement accuracy wNStandard: ±3 % of measured value + (0.4 % of measuring range; min. 0.08 m/s 1)
High precision: ±1 % of measured value + (0.4 % of measuring range; min. 0.08 m/s 1)
Response time (t90) wN3 s (jump of wN from 0 to 5 m/s in air)
Temperature gradient wN< 8 K/min (at wN = 5 m/s in air)
Recovery time wN< 10 s (after temperature change of ∆ϑ = 40 K and at wN = 5 m/s in air)
TM (wN > 2 m/s)± 2 K (TM = 10 ... 30 °C)
± 4 K (in remaining measuring range)
Operating temperature
Sensor head0 … +200 / 0 … +350 °C (optional)
Electronics-20 … +70 °C
Storage temperature-20 … +85 °C
HumidityNon-condensing (≤ 95 %); high relative air humidity in combination with high temperature can cause measurement deviations
Operating pressureAtmospheric (700 … 1,300 hPa) / 16 bar (optional; over pressure)
Electronic data
Supply voltage24 V DC ± 20 %
Current consumptionTyp. 50 mA (max. 250 mA)
Display4 x Duo-LEDs (green / red / orange)
Start up timeApprox. 10 s after switch-on
Type / class of protectionIP65 (housing), IP54 (probe) / III (SELV) or PELV (EN 50178)
Analog outputs ( wN, TM)Auto-U/I: 0 … 10 V / 4 … 20 mA (signal characteristic depends on RL)
Voltage output: RL ≥ 550 Ω (short-circuit protected)
Current output: RL ≤ 500 Ω
Change-over hysteresis: 50 Ω
CL ≤ 10 nF
Pulse outputs: Technology1. Highside-driver (open collector at protected supply voltage; not galvanically isolated)
High level: > supply voltage - 3 V
2. Semiconductor relay (galvanically isolated), max. 30 V / 50 mA
Pulse outputs: Signalization0 … 100 Hz or 1 impulse / m3 or free selectable frequency (10 … 100 Hz)
Fieldbus (optional)Profibus DP / DeviceNet
Electrical connectionPlug-in connector M12 (A-coded), male, 8-pole (shielded), screwed
Maximum cable lengthVoltage interface: 15 m / Current interface (pulse outputs): 100 m
Mounting positionArbitrary (atmospheric; under higher pressure preferred horizontally)
Installation tolerance± 3° relative to flow direction
Weight550 g max. (400 mm input length) / 800 g (field bus version)
Probe length (L)250 / 400 / 600 / 1,000 mm (both versions)
Cable length (remote version)Selectable: 1 … 10 m (in steps of 10 cm)
Material
HousingAluminium, anodised
Sensor tubeStainless steel 1.4571
Sensor headPlatinum resistor element (glass-passivated), ceramics
Compression fittingStainless steel 1.4571 or brass (depending on sensor option)

1) under reference conditions, related to adjustment reference

Order information

 DescriptionArticle number
Basic sensorSCHMIDT® Flow Sensor SS 20.6511546650-ABCDEFGHDD
 Options
 Standard 1        

Output signals

Basic (2 x analogue auto-U/I plus 2 x impulse)  1       
Profibus DP-V0  2       
DeviceNet  3       
Mechanical versionBasic (compact version with fixed probe)   1      
Remote version with cable length: _____ mm (1 ... 10 m)   2      
Probe length 250 mm    1     
Probe length 400 mm    2     
Probe length 600 mm    3     
Probe length 1,000 mm    4     
Measuring range and adjustmentMeasuring range 0 ... 2.5 m/s     1    
Measuring range 0 ... 10 m/s     2    
Measuring range 0 ... 20 m/s     3    
Measuring range 0 ... 40 m/s (only at H = 3 or 4)     4    
Measuring range 0 ... 60 m/s (only at H = 3 or 4)     5    
Standard adjustment      1   
Standard adjustment with factory calibration certificate      3   
High precision adjustment, including factory calibration certificate      2   
Impulse outputStandard: wN ~ f = 0 ... 100 Hz (wN, max = fmax)       1  
1 Impulse/m3 for pipe diameter (round): _____ mm (min. 20 mm)       2  
Selectable fmax: _____ Hz (10 ... 100 Hz)       9  
Temperature and pressure200°C atmospheric        1 
200°C atmospheric (coated)        2 
200°C pressure-tight        3 
200°C pressure-tight (coated)        4 
350°C atmospheric        5 
350°C pressure-tight        6 
Pressure DD: ___ (00 ... 16 bar; 00 = atmospheric; > 1 bar overpressure)         00 … 16

Accessories

Connection Technology

DescriptionArticle-Number
Connecting cable 8-pin, length 5 m, with coupler socket and open cable ends524 921
Coupler socket 8-pin, cable length selectable, (2 … 100 m; 1-m-steps), free of halogen, with cable end sleeves524 942
Coupler socket 8-pin, with screw connections, for cable diameter ø 6 ... 8 mm524 929
Power supply: out 24 V DC / 1 A; in 115 / 230 V AC (strip terminal)535 282

Mounting and Fixing Technology

DescriptionArticle-Number
Compression fitting SS 20.651 HT-p = 350 °C525 734
Welding sleeve G½, steel, according to EN 10241, 5 pieces524 916
Welding sleeve G½, stainless steel 1.4571, to EN 10241, 2 pieces524 882
Assembly kit for pipe assembly suitable for MD 10.010/10.015, including pipe clamps and collar for adjustment for the pipe diameter531 394

Measured Value Display

DescriptionArticle-Number
LED display MD 10.010 in wall housing to show volume flow and flow velocity, 85 … 250 V AC and sensor power supply527 320
LED display MD 10.010, similar to 527 320 but with 24 V DC voltage supply528 240
LED display MD 10.015, similar to 527 320 but with an additional sum function and a second measuring input527 330
LED display MD 10.015, similar to 527 330 but with 24 V DC voltage supply528 250

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