ASL1600

Media Isolated Liquid Mass Flow Meter

www.sensirion.com May 2009 V1.1 1/9

ASL1600 Product Summary

The ASL1600 Liquid Mass Flow Meter enables

extremely fast and accurate measurements of ultra low

liquid mass flows. This particularly small and light device

operates with total media isolation, hardly any dead

volume and no moving parts. The unique performance of

this Swiss made device is based on Sensirion’s

unsurpassed CMOSens

sensor technology which

combines a high precision thermal sensor element with

the amplification and A/D converter circuit and digital

signal processing on one single CMOS chip. This results

in superior resolution, fast response time and large

dynamic range at low power consumption.

All measurement data is fully calibrated and temperature

compensated by means of an internal microcontroller.

Excellent chemical resistance and bio-compatibility are

ensured. The medium only gets in contact with the

straight sensor capillary made of Duran

- (borosilicate

glass 3.3), with the PEEK™-fittings and with Teflon

used as sealing material. Typical applications for this

sensor include precise liquid mass flow and volume

measurement for analytical instruments, medical

devices, process control.

The ASL1600 requires a supply voltage of 7…18 V

and provides an RS-232 compliant digital interface.

CMOSens

Technology

CMOSens

is the base technology for all Sensirion

microsensor products. The unification of CMOS and

sensor technology serves as a platform for highly

integrated system solutions with excellent sensor

precision and reliability. Inside the ASL1600 the on-chip

sensor element forms an integrated whole with a high-

end amplification A/D converter circuit. Due to this

compact single-chip design, CMOSens

based sensors

are very resistant to electromagnetic disturbances (EMC),

another important technical advantage of this state of the

art sensor technology. As a result, CMOSens

based

sensor modules offer excellent sensor precision, fast

response time and a very large dynamic measurement

range. In addition, the digital intelligence of the

CMOSens

sensor technology enables digital interfaces

that permit an easy link with the system of the customer,

a real advantage and benefit that results in ready-to-use

problem solutions.

The core element of CMOSens

liquid mass flow

sensors is formed by mounting the highly sensitive

microchip on the outside of a straight glass capillary (

Patent 6,813,944 B2

). The liquid mass flow in the

capillary is measured through the tubing material

guaranteeing a total media isolation.

Enlarged View

Digital Signals from Chip

CMOS Sensor Chip

Calorimetric Sensing Principle

Measure through tubing material

Sensor Capillary

2009 V1.1

−

Totally non-invasive

− Maximum flows up to 4 ml/min

− Resolutions down to 100 nl/min

− Response time 30 ms

− RS-232 digital interface

ASL1600 Liquid Mass Flow Meter

www.sensirion.com May 2009 V1.1 2/9

1 Liquid Mass Flow Sensor Performance

Table 1: Overview ASL1600 Liquid Flow Sensor Performance (all data for 23°C, 1 bar

abs

unless otherwise noted).

Parameter Condition ASL1600-10 ASL1600-20 Units

Liquid Flow Sensor

Maximum Flow (bi-directional) 1000 4000 µl/min

Calibrated Minimum Flow 40 200 µl/min

Flow ≥ Calibrated Minimum Flow

3.0

a,d

3.0

a,d

% of measured value

Accuracy

Flow ≤ Calibrated Minimum Flow

0.15

a,d

0.15

a,d

% of full scale

Best Resolution

at calibrated min. flow 0.1 0.3

µl/min

at maximum flow 1.5 5.0 µl/min

Pressure Drop at maximum flow <100 <100 Pa

Repeatability reference conditions

<0.8 <0.8 % of measured value

Overpressure related Offset 0 0 % FS / bar

Overpressure Resistance

5 3 bar

Flow Detection Response Time 30 30 ms

Digital Sampling Time

(Data Readout)

depends on resolution

setting (see Table 2)

5 5 ms

Operating Temperature avoid freezing +0…+60 +0…+60 °C

25%…75% of max. flow

<0.2 <0.2 % MV / K

Temperature Coefficient

<25% or >75% of max flow

<0.4 <0.4 % MV / K

Mounting Orientation

Sensitivity

<1.5 <3 % of full scale

Temperature Sensor Measures temperature inside the sensor chip, but not of the surrounding air

Dynamic Range +10…50 +10…50 °C

Resolution 0.1 0.1 °C

Accuracy 3 3 °C

Table 2: Resolution at Different Flow Levels and Integration Times

Better available on request. For best results allow the sensor to warm up.

See Table 2

1 bar = 100 000 Pa = 0.9869 atm = 401.9 inch H

O = 14.5 psi

Reference conditions: 1 bar

abs

, T= 20°C, medium H

O, vertical mounting (electrical connector up)

Overpressure in operation; High overpressure resistance for OEM-solutions on request

For low flow measurements with high accuracy vertical mounting position (connector up) is recommended

The chip warms up by about 4K (depending on supply voltage and ventilation)

Sensor Resolution

Readout

Frequency

200 Hz

Readout

Frequency

50 Hz

Readout

Frequency

12.5 Hz

Readout

Frequency

1.56 Hz

Best Resolution to be multiplied by ...

64 16 4 1

Mass Flow Integration Time

5 ms 20 ms 80 ms 640 ms