ASF1400 Bidirectional Mass Flow Meter

ver

↵

version

Provides type of sensor, software, hardware and customer version

get

↵

Start single measurement

go

↵

Starts series of measurements

s

stop

Stops series of measurements

reset

↵

Resets ASF1400 device

res=1..9

↵

resolution

Sets resolution: 1 -> 12 bits; 9 -> 15 bits, see Table 2

res?

resolution

Shows actual setting

mod=F | T

↵

mode

Selects Flow- (F) or Temperature mode (T)

mod?

mode

Shows actual setting

Disp=s,d

display mode

Shows Flow (s) or Flow+Temperature (d)

*no effect in the Temerature mode

Disp?

display mode

Shows actual setting

defspi=P | G

↵

define spi

Sets SPI in Push- (P) or Get mode (G), see also Section 4.3

Notes:

• Default settings are marked in bold letters

• The commands are not case sensitive.

• In order to send a new command to the ASF1400 make sure the ASF1400 is not in measurement mode. Issue therefore a stop command

s first. After this, any instruction can be given to the ASF1400 and a new series of measurement can be started by go

↵.

4 Specifications ASF1400

4.1 Absolute Maximum Ratings

Ambient storage temperature

-65°C to 150°C

Ambient operating temperature

0°C to 70°C

Overpressure resistance

2.0 bar

4.2 Electrical Specifications

Table 3: ASF1400 DC Characteristics.

Parameter

Conditions

Min.

Typ.

Max.

Units

Power Supply DC

DC

7

9

18

V

VDD = 9 V, no load

20

mA

Operating Current

27

mA

VDD = 9 V, 3k

Ω at RS232 output

Power Dissipation

VDD = 9 V, no load

180

mW

Table 4: ASF1400 RS-232 Characteristics.

Parameter

Conditions

Min.

Typ.

Max.

Units

RS232 Output

Transmitter output loaded

with 3k

Ω

±5

±9

V

Output Voltage Swing

Power-Off Output Resistance

300

Ω

Output Short Circuit Current

±18

mA

RS-232 Input

Voltage Range

-15

15

V

Voltage Threshold

Low

0.8

1.2

V

High

1.7

2.4

V

Hysteresis

0.2

0.5

1.0

V

Resistance

3

5

7

k

Ω

www.sensirion.com

Version 2.2

6/9