ASF1400 Datasheet, PDF (5/9 Pages) List of Unclassifed Manufacturers – Bidirectional Mass Flow Meter

ASF1400 Bidirectional Mass Flow Meter
2 Pins and Digital Interface
T xD
R xD
SCK
M IS O
M OSI
/C S
VDD
GND
The measurement values are provided as a signed
floating point number together with the corresponding
unit (sccm for mass flow, C for temperature). In case
of an overflow, the output shows oF.
2.3 Serial Peripheral Interface (SPI)
The in earlier versions available SPI interface is due
to changes in electronic components no longer
supported.
Figure 6: ASF1400 pin out.
GND and VDD (Power Supply)
The ASF1400 requires a voltage supply of between 7
V and 18 V. Since this voltage is internally regulated,
there are no stringent requirements as far as ripple
and stability are concerned.
2.1 Connector
You need an EDAC 395-010-520-102 connector to
connect the sensor. Please check the EDAC
homepage for details (www.edac.net).
Alternatively the AVX 00 6338 020 000 04 0 or AVX
00 6338 020 000 04 2 connectors can be used to
connect the ASP1400 as well. (See www.farnell.com,
order codes 635789 or 635730).
2.2 RS-232 Interface
All configurations (see also Section 3) for the
ASF1400 can be set using its RS-232 interface). To
communicate with the ASF1400 via RS-232 the
following pins are required:
RxD (Receiving Data Line)
TxD (Transmitting Data Line)
GND (Ground)
The RS-232 of the ASF1400 is configured as follows:
Baudrate
9600
Data Bits
8
Stop Bits
1
Parity
none
Protocol
none
With these settings, the ASF1400 device can be
connected to any PC or PDA equipped with terminal
software.
3 Configuration and Commands
The ASF1400 device accepts a set of commands
through its RS-232 interface (see table 3 for valid
commands; for correct settings of the RS-232 refer to
Section 2.1).This allows the user to configure the
ASF1400 device. Since the configuration is stored in
the internal EEPROM, it is maintained after power
breaks.
With the exception of the stop s command, all
commands have to be terminated by the return key
(↵, ASCII #10 or #13). After completion of a
command, the ASF1400 returns ok and is ready to
take a new instruction. Before entering a command, it
may be necessary to clear the buffer by means of
using ↵.
There is a trade-off between resolution and
measurement time. Possible settings are listed in
Table 2. Choosing 12 bit results in a measurement
interval of 142 ms. With the max resolution of 15.2 bit,
a new measurement is provided every 1280 ms. For
faster sampling rates refer to the ASF1430 high
speed mass flow meter device data sheet.
Table 2: Resolution settings using the res=value
command and corresponding response times
res=
Resolution [bit] data interval [ms]
1
12.0
142
2
13.0
284
3
13.5
427
4
14.0
569
5
14.3
711
6
14.6
853
7
14.8
995
8
15.0
1138
9
15.2
1280
Table 3: Commands of the ASF1400 device.
Command
help↵
Output
commands
Description
Lists all available commands
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Version 2.2
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