There are different models to select from in-line and on-line methods of installation.

S421 inline Consumption meter for compressed air and gases

The consumption sensor S421 is based on the thermal mass flow principle. It measures volumetric standard flow over a wide measuring range. The result is pressure and temperature independent. S421 is an in-line type sensor which is mounted into the pipe. There are 7 models available for ¼”, ½”, ¾”, 1” , 1 ¼”, 1 ½”, and 2” tubes. The version with display shows the actual volumetric flow and the total consumption. The consumption counter can be set via the keyboard. Various settings such as gas type, flow unit, reference standards, can be set ex factory or through our service kit. The service kit consists of a PC software and a interface box which connects the sensor to the USB port of the PC. Every sensor includes an analogue output (4…20mA) for flow and an isolated pulse output for the consumption counter.


Easy and affordable installation

Units freely selectable via keypad m³/h, m³/min, l/min, l/s, kg/h, kg/min, kg/s, cfm

Compressed air counter up to 1,999,999,999 m³

Analogue output 4…20 mA, pulse output (galvanically separated)

High measuring accuracy also in the lower measuring range (ideal for leakage measurement)

Negligible small loss of pressure

Thermal mass flow principle

Gas type adjustable via software (N2, O2, CO2, N2O, Ar)

Application range

Compressed air balancing, compressed air consumption measurement

Leakage air / leak rate determination

Mobile compressed air measurement in front of single machines/plants

Flow measurement of process gases like e.g. N2, O2, CO2, N20, Ar

Flow measurement at nitrogen generators

Technical information

Measured units: m³/h, m³/min, l/min, cfm, m/s, kg/min, kg/h, kg/s
(Reference standard can be programmed)
* Air: Ps= 1000 hPa, Ts= 20 ºC
Other gases: Ps= 1013, hPa, Ts= 0 ºC
Accuracy: +/- (2% of measured value + 0,3% full scale)
Temperature drift: 0.05% / K
Pressure drift: 0.5% / MPa
Stated accuracy at: Ambient/process temperature 23 ºC +/- 3 ºC
Ambient/process humidity <90%, no condensation
Process pressure 0.6 MPa
Process connection: R thread (ISO 7-1),
Flange EN 1092-1, ANSI / B16.5, JIS B2220
Principle of measurement: Thermal mass flow
Sensor: Glass coated resistive sensor
Measuring medium: Air, N2, O2, Ar, N2O, CO2
Operating temperature: -30 up to +50°C / -10 to +50°C with local display
Operating pressure: up to 1.6 MPa / up to 4.0 MPa (optional)
Analoge output: Signal: 4 ... 20 mA
Scale: 0 to maximum volume flow
Accuracy: 0.06 mA
Pulse output: 1 pulse per m³, l, ft³ of kg, insulated switch
Output max 30 VDC, 20 mA
(pulse length: 30 - 120 ms, depends on consumption rate)
Power supply: 12-30 VDC, 100 mA
Display: 128 x 64 pixels, with backlight
Material: Measurng section: Stainless steel 1.4404 (sus 316L)
* Ps= Standard pressure
* Ts= Standard temperature

Insertion on-line S401 – S452 series

S401 Flow meter

The S401 flow sensor  is based on the thermal mass flow principle. It measures volumetric standard flow over a wide measuring range. The result is pressure and temperature independent.
The sensor installation into the pipe is done through a ½” ball valve. This makes it possible to do the installation under pressure without shutting down the compressed air line. The sensor is available in two measuring ranges and with or without display. The version with display shows the actual volumetric flow and the total consumption. Via the keyboard tube diameters and the consumption counter can be set.

Every sensor includes an analogue output (4…20mA) for flow and an isolated pulse output for the consumption counter.

When installing the sensor a straight stretch of 15 times the inner diameter of the pipe is required at the inlet (up stream) of the sensor probe and 5 times the inner diameter at the discharge (down stream) of the probe. To avoid disturbing the laminar flow it’s advised not to use T-connectors, but only a hot tap or drill collar!

Characteristics and advantages

  • Insertion type sensor for installations under pressure
  • Thermal mass flow, independent of pressure and temperature changes
  • Velocity, flow and consumption can be displayed
  • IP65 casing provides robust protection in rough industrial environment
  • Very fast response time
  • High accuracy and wide measuring range
  • Tube diameters of 1" to 12". Other diameters on request

Technical information

Measured unit: m³/h, m³/min, l/min, cfm, m/s, kg/min, kg/h, kg/s
Accuracy: ± (3% of measured value +0.3% full scale)
Medium: Air, gas, non explosive
Operating temperature: -30... 140°C - probe tube
-30... 70°C - casing
-10... 50°C - casing with local display
Operating pressure: Up to 5.0 MPa
Analogue output: Signal: 4...20 mA
Scaling: 0... max range
Max. load: ≤ 500R
Pulse output: 1 pulse per consumption unit, insulated switch output, max. 30 VDC, 20 mA
Power supply: 12...30 VDC, 100 mA


S430 Pitot tube flow sensor - measures flow, consumption, pressure and temperature

S430 is based on the pitot tube principle to measure flow.

Properly installed the sensor can measure in wet and dirty gases as occurring, for example, at the discharge of a compressor. Through the internal self-calibration the sensor features long term stability, wide turn-down ratio and good

temperature stability. It can be used in compressed air and non-corrosive gases. Through a 1/2” G-type ball valve the sensor can be inserted into the pipe under pressure. Various output signals allow the sensor to be connected to our displays and/or third party displays and PLCs.

Features and advantages
• Flow and consumption measurement in wet air or high mass flow / velocity applications
• Insertion type, easy installation under pressure through ball valve possible
• High temperature applications up to 200 °C
• No mechanical wear parts
• Measurement at compressor outlet possible
• All parts which are in contact with flow medium are made of stainless steel

Technical information

Flow range: 10..200 Sm/s
Sm/s: Standard meter per second at 20ºC and 1000 hPa
Pressure range 0...1,6 MPa
Temperature range: -40...+200ºC
Accuracy: Flow: 0.5 % F.S.
Pressure: 0.5 % F.S.
Temperature: 0.5ºC
Pipe diameter DN25 (1") up DN300 (12")
Reference conditions Programmable, default P=1000 hPa and T=20ºC
Medium: Wet and dry air and non corrosive gases
Output signal: 4..20mA (flow value)
Pulse (consumption)
Modbus/RTU (all signals available)
SDI (CSiTEC specific)
Medium temp.: -40...200ºC
Ambient temp. -20...60ºC
Operation pressure: 0....1.6 MPa
Power supply 24 VDC, 150 mA
Display options 2" color- & graphics display with keypad
Process connection: 1/2"G type

S450 Heavy duty industry Flow meter

S450 has been designed for harsh environments. The NEMA 4X housing with IP67 is able to withstand all weather conditions. All parts which come into contact with the measuring device are manufactured from stainless 316L steel. This enables the use of the sensor in the pharmaceutical and food industry but also for measuring aggressive and polluted gas.

The measuring of compressed air and gasses in explosion sensitive areas is made possible through choosing the ATEX implementation. Various gases can be measured, such as air, oxygen, argon, CO2, natural gas, hydrogen, methane and so forth. In principle, any gas mixture is to be measured when its components are known and its composition is constant.

In the modern production world instrumentation should provide interfaces to the existing factory and automation systems. S450 compressed air flowmeters supports a wide variety of connection forms which include the traditional 4…20 mA and pulse output, fieldbus interface for HART, Modbus and M-Bus. The C450 has been modularly developed and the desired form of connection is easily chosen.


  • Direct measurement of mass flow and standard flow without the need for pressure compensation
  • Wide range of tube sizes are supported with insertion type for big pipe diameters and in line types for small pipe diameters
  • No moving parts, non clogging
  • All parts which come into contact with the measurement medium are manufactured from stainless 316L steel
  • Robust metal enclosure suitable for out-door applications in harsh environments.
  • Wireless Bluetooth interface for sensor settings on site
  • Display shows flow rates, consumption, medium temperature and diagnostic results
  • 2 analogue outputs (4-20 mA) and 1 pulse output
  • Available options:
    • Fieldbus interface: HART, MODBUS, M-BUS
    • Hazardous approval ATEX: II 2 G Ex d IIC T4
    • 2 directional measurement
    • Flow conditioning

Technical information

Measuring range: 0.4 ... 92.7 sm/s *(standard range calibration)
0.8 ... 185 sm/s *(max calibration)
*sm/s: standard meter per second
Accuracy: ±1.5% of reading +0.3% full scale
Stated accuracy at: Ambient/process temperature 23ºC +/-3ºC
Ambient/process humidity <90%, no condensation
Process pressure at 0.6 MPa
Repeatability: 0.25% of reading
Response time
< 5 seconds
Sampling rate: Display and outputs are refreshed every 200 msec.
Tube diameter: Insertion type: DN25...DN1500
In line type: DN15...DN80
Process connection: Insertion type: ½" G type thread (ISO 228-1)
In line type: R thread (ISO 7-1), Flange EN 1092-1, ANSI 16.5, JIS B2220
Measuring medium: Any gas where the components and the mixing ration are constant and known.
See order information for a list of standard gases.
Operating temp.: -40 ... +150°C (medium temp. insertion type)
-40 ... +100°C (medium temp. in line type)
-40 ... +65°C (ambient temp.)
Operating pressure: 1.6 MPa (16 bar) - insertion type
4.0 MPa (40 bar) - in line type
Analogue output: 2 x 4 ... 20 mA, up to 500 R load, active/passive selectable, measurement channel selectable, scaling programmable
Pulse/Alarm output: Alarm or pulse output. 1 pulse per 1, 10 or 100 consumption units. Alarm programmable.
Power supply: 16-30 VDC, 7 W
Housing: NEMA 4X, IP 67
Sensor material: Stainless steel 316L
Approval: CE, RoHS
ATEX : II 2 G Ex d IIC T4 (Optional)
Fieldbus (Optional): MODBUS, HART, M-BUS
Configuration interface: Service kit