ASF1400 Datasheet ASF1400 | P1-P3

www.sensirion.com Sensirion AG, Laubisrütistrasse 50, CH-8712 Stäfa ZH, Switzerland, Phone: +41 44 306 40 00, Fax: +41 44 306 40 30

ASF1400

Bidirectional Mass Flow Meter

_ Unique dynamic range:

0.01 sccm – 400 sccm

_ Outstanding resolution and accuracy

_ Ultra fast response time

_ Hysteresis & offset free

_ Calibrated & temperature compensated

_ RS-232 and

ASF1400 Product Summary

The ASF1400 Mass Flow Meter enables extremely

accurate bidirectional measurement of gas flow over four

orders of magnitude. Its leading performance is based on

SENSIRION’s unsurpassed CMOSens

sensor technology.

With CMOSens

, the on-chip sensor element forms an

integrated whole with the amplification and A/D converter

circuit. This results in superior resolution, fast response

time and large dynamic range at lowest power

consumption.

All measurement data is fully calibrated and temperature

compensated by means of an internal microcontroller.

Mounted in rugged, chemically inert PBT housing the

ASF1400 is suitable for a wide range of applications. Such

include mass flow metering for process control, medical

applications, heating ventilation and air conditioning

(HVAC) solutions, as well as gas flow metrology.

The sensor housing provides two inlets for measuring the

gas flow and withstands overpressures of 2 bar (29 psi).

The ASF1400 requires a supply voltage of 7…18Vdc and

provides an RS-232 compliant electrical interface.

Version 2.2 / November

MASS FLOW

VOLTAGE

REGULATOR

MICRO

CONTROLLER

RS232 LINE

DRIVER/

RECEIVER

EEPROM

GND

VDD

/CS

MOSI

MISO

SCK

RxD

TxD

MASS FLOW

ASF1400 MASS FLOW METER

SPI

Interface

RS232

Interface

Power

Supply

CMOSens

™

SENSOR CHIP

THERMAL

SENSOR

AMPLIFIER

ADC

no longer

supported

Figure 1: Block Diagram ASF1400 Mass Flow Sensor with CMOSens

technology.

ASF1400 Bidirectional Mass Flow Meter

Introductory Description

The heart of the ASF1400 mass flow meter is

sensor technology. The ASF1400 mass flow meter

therefore provides unbeatable performance at very

attractive system cost. The lowest detectable gas flow

rate is 0.003 sccm, which means a minimum volume

of 3 mm

gas per minute can be measured. Covering

at the same time a flow range of more than 4 orders

of magnitude, the ASF1400 sets a new standard

wherever mass flow has to be measured or

controlled.

The ASF1400 device measures true mass flow

independent of the ambient temperature and pressure

changes. You simply connect the gas to be measured

to the ASF1400 device to get an instantaneous gas

flow rate at a sampling rate of up to 7Hz (please

A flow range between ±400 sccm can directly be

mea-sured by connecting the ASF1400. To increase

the range, a bypass can be used in conjunction with

the ASF1400 device (see Section 1.4 of this data

sheet).

In addition to mass flow, the ASF1400 device

provides information about the temperature on the

CMOSens

sensor element. Both mass flow and

temperature data are accessed through an RS-232.

The RS-232 interface allows you to directly connect

the ASF1400 device to a PC or PDA using standard

terminal software. If a special interface such as 4-20

mA current output or other is required contact

Sensirion for a customer specific solution.

In general, all gas types can be measured using the

ASF1400 product. However, the standard calibration

gas is nitrogen. Please contact SENSIRION, if you

would like to use the sensor for applications with other

gases.

To get you started quickly, an evaluation package

including ASF1400 devices, software, cables, rubber

hose and bypass is available from Sensirion AG.

CMOSens

sensor technology

CMOSens

is the base technology for all Sensirion

multi sensor modules and sensor systems. The

unification of semiconductor chip and sensor

technology serves as a platform for highly integrated

system solutions with excellent sensor precision and

reliability. With CMOSens

, the on-chip sensor

element forms an integrated whole with a high-end

amplification and A/D converter circuit. Due to the

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 multi 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 (“Mount&Sense”).

www.sensirion.com Version 2.2 2/9

ASF1400 Bidirectional Mass Flow Meter

1 Mass Flow Sensor Performance

Table 1: Overview of ASF1400 Gas Sensor Performance

Parameter Condition Minimum

Typical

Maximu

Units

Flow Sensor

direct measurement -400 400 sccm

( )2

using proposed bypass tube

(2 )3

-100 100 liter/min

( )4

Dynamic Range

customized bypass tube unlimited

unlimited

Resolution 400 sccm flow 0.09 sccm

< 10 sccm flow 0.01 sccm

Lowest Detectable

Flow

< 10 sccm flow 0.015

(4)

sccm

Pressure Drop 400 sccm, p

abs.

= 1 bar 120 Pa

( )5

Repeatability

0.0025 % FS

( ) 6

0.025 % m.v.

0…5 % of full scale 0.05 % FS

( ) 7

Accuracy 23 C

5…100 % of full scale

1 % m.v.

( ) 7

Offset 23°C < 0.005 < 0.02 % FS

Overpressure

Resistance

2 bar

( )8

depends on resolution setting

142 1280 ms

Response Time

( )9

(see Section 3, Table 2)

Operating

Temperature

0 70 °C

Zero < 0.005 % FS / °C Ambient

Temperature

Coefficient

Span < 0.08

% measured value /

°C

Position Sensitivity p =1 bar, small nitrogen flow ±0.008 % FS

abs

Temperature

Sensor

Measures temperature inside the sensor, but not of the surrounding air

(10 )10

Dynamic Range 0 70 °C

Resolution 0.1 °C

Accuracy 3 2 °C

All data apply for calibration conditions (20°C, 1013 mbar) unless otherwise noted.

1 sccm = 1 cm

/min at 0°C and 1013mbar pressure (1sccm = 0.001 norm liter)

using bypass tube included in Sensirion’s mass flow meter evaluation kit EK-F1

1 liter/min = 1000 sccm

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

O = 14.5 psi

Error = % of full scale (FS) or % of measured value, whichever is bigger.

Better calibration available for high volume OEM on request. Allow the Sensor to warm up for best results.

For higher overpressure resistance versions please check the EM1 product page.

For faster response times please check out the ASF1430 high speed mass flow meter data sheet

The sensor warms up by about 7°C (depending on supply voltage and ventilation).

www.sensirion.com Version 2.2 3/9

P1-P3 P4-P6 P7-P9

ASF1400

Mfr. #:

Buy ASF1400

Manufacturer:

Sensirion

Description:

Flow Sensors Sensor device

Lifecycle:

New from this manufacturer.

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