700-SDI-RADAR-300WL-Man Rev 2 11 Apr Mar 2022
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Part# 21371
HS PROTOCOL
The request is sent from the data logger to the flow meter:
<0x25> ID CSUM
0x25:
The first byte sent in the request is % character. Its ASCII value in HEX is 0x25.
ID:
Exactly two bytes long. This is the unit ID written as two ASCII characters.
For example, if the polled unit ID is 2, then ID will be sent as “02”. In HEX
representation it is the following two bytes: <0x30><0x32>.
CSUM:
Checksum, calculated by adding in modulo 256 the two byte values of the ID.
If the device ID is 2, then ID was sent as <0x30><0x32>.
Checksum is then 0x30+0x32 = <0x62>.
After receiving the request, if the device ID matches, the flow meter will respond with the current
averaged flow velocity reading:
<0xA5> ID SPEED CSUM
0xA5:
The first byte sent in the response is byte with HEX value of 0xA5.
ID:
Exactly two bytes long. This is the unit ID written as two ASCII characters.
For example, if the unit ID is 2, then ID will be sent as “02”. In HEX representation
it is the following two bytes: <0x30><0x32>.
SPEED:
The speed readout in currently selected units, formatted as real (float) number
With exactly three digits after the decimal dot separator.
For example, if the current averaged speed is 5.7143, it will be reported as
5.714, or in HEX values: <0x35><0x2E><0x37><0x31><0x34><0x33>.
LEVEL:
The level readout in meters, formatted as real (float) number with exactly three
digits after the decimal dot separator.
For example, if the current averaged level is 5.7143, it will be reported as
5.714, or in HEX values: <0x35><0x2E><0x37><0x31><0x34><0x33>.
CSUM:
Checksum, calculated by adding in modulo 256 the two byte values of the ID and
All byte values from the SPEED.
Second possible command is sent from the data logger to the flow meter:
<0x2b> ID CSUM
0x2b: The first byte sent in the request is ‘+‘character. Its ASCII value in HEX is 0x25.
ID: Exactly two bytes long. This is the unit ID written as two ASCII characters.
For example, if the polled unit ID is 2, then ID will be sent as “02”. In HEX
representation it is the following two bytes: <0x30><0x32>.
