ECM BB100, Instruction Manual, Page: 22 / 37

Download Value Command
A “Download Value” command to the BB100 consists of a header, an index, the four byte
floating point value and a two byte checksum. A total of 12 bytes must be sent. The index is
considered an array index (to a float value) in the BB100. Any indices not in the range
specified below should never be changed by the external computer. Values successfully
received by the BB100 are acknowledged by <D0> <D0>. A checksum failure is reported by
<D1> <D1>.
The “Download Value” command format is:
<C8> <C8> <C8> <C8> <DB> <index> <value> <checksum 1> <checksum 2>.
This command is used to download the flow calibration curve. The calibration curve
consists of flow rate data in LPM at a fixed frequency interval. The curve contains 51 points,
starting at 0.0Hz with data values at an interval of 200.0Hz. A download index of zero
corresponds to 0.0Hz, and a download index of 50 corresponds to a frequency of 10,000.0Hz.
The BB100 provides the frequency as part of the packet of real-time data uploaded with a
poll command.
Upload Selection Command
An “Upload Selection” command to the BB100 consists of a header and the one byte index
sent twice. A total of 7 bytes must be sent. There is no checksum sent with this type of
command. Index values are listed in the “Download Selection” command section. This
command is not acknowledged.
The “Upload Selection” command format is:
<C8> <C8> <C8> <C8> <DC> <index> <index>.
In response to this command, the BB100 uploads the one byte selection value twice, for a
total of two bytes. This allows for error checking since the two bytes must match to be
considered valid data.
Upload Value Command
An “Upload Value” command to the BB100 consists of a header and the one byte index sent
twice. A total of 7 bytes must be sent. This command may be used to upload the flow
calibration curve. The calibration data format is given in the “Download Value” command
section. This command is not acknowledged.
The “Upload Value” command format is:
<C8> <C8> <C8> <C8> <DD> <index> <index>.
In response to this command, the BB100 uploads the four byte floating point value and a two
byte checksum for a total of six bytes.
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