ECM BB100, Инструкция по эксплуатации, Страница: 21 / 37

Control Commands
A “Control” command to the BB100 consists of a header and the command number sent
twice. A total of 7 bytes must be sent. There is no checksum sent with this type of
command. The Control command format is:
<C8> <C8> <C8> <C8> <D9> <command> <command>
For example, command number 2, the poll command (send a packet of flow data to the
remote computer), would be sent as:
<C8> <C8> <C8> <C8> <D9> <2> <2>.
The valid Control command numbers and their functions are as follows:
1: Upload status byte. Returns <A2> <A2> if the BB100 is ready to accept serial port
commands.
2: Poll command. This command causes the uploading of a packet of flow data. The data
is sent as <C8> <C8> <C8> <C8> <LPM> <CFM> <Liters Total> <Ft
3
Total>
<Frequency> <checksum byte 1> <checksum byte 2>. The flow data is uploaded in four
byte floating point number format. The packet of data is 26 bytes long. This command
is not acknowledged.
3: Clear total flow values. Sets both the Liters Total and the Ft
3
Total values to zero.
Equivalent to pressing the “CLR” key on the front panel. This command is
acknowledged.
8: Clear BB100 serial port receive buffer. May be used to recover from serial port data
errors. This command is acknowledged.
Download Selection Command
A “Download Selection” command to the BB100 consists of a header, an index, and the one
byte value sent twice. A total of 8 bytes must be sent. There is no checksum sent with this
type of command. Index values are listed below. Any indices not listed below should never
be changed by the external computer. Values successfully received by the BB100 are
acknowledged by <D0> <D0>. A data error is reported by <D1> <D1>.
The “Download Selection” command format is:
<C8> <C8> <C8> <C8> <DA> <index> <selection> <selection>.
The valid index values and selections are:
Index Function Valid Values
1 Operating Mode 0=LPM, 1=CFM, 2=Liters Total, 3=Ft
3
Total
3 UpdateRate 0=Slow, 1=Average, 2=Fast
4 Analog Output at 5V for LPM 0=10.0, 1=50.0, 2=100.0, 3=150.0
5 Analog Output at 5V for CFM 0=0.4, 1=2.0, 2=4.0, 3=6.0
6 Analog Output at 4.5V for Liters Total 0=10.0,1=100.0,2=250.0,3=500.0,4=1000.0
7 Analog Output at 4.5V for Ft
3
Total 0=0.4,1=4.0,2=10.0,3=20.0,4=40.0,5=100.0
8 Flow Averaging Period (sec) 0=0.1,1=0.2,2=0.5,3=1.0,4=2.0,5=5.0,6=8.0
Specifications and Limits 17