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ELD sends handshake response
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SeeLeveL sends reply to original ELD request if handshake response is
correct and on time.
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The "handshake accepted acknowledge" message is not used here.
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Upon power-up of the display, the "20 requests" is reset so a
handshake is needed for the first liquid level request.
The alarms are not currently supported. In the future, if they are:
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The content of Message $08 is alarm set point, high or low level
alarm, and current alarm status.
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The content of Message $0A is just a short form of Message $08,
alarm status only.
The SeeLeveL will respond to source addresses of 0x00 (ELD) only.
The SeeLeveL will not respond at all to any message that has errors, has
an invalid message, is not addressed to SeeLeveL, does not come from
0x00 (ELD), and does not follow the handshake protocol. This avoids
unnecessary bus activity and possible contention, and makes it harder to
break the code with repeated attempts using different values.
Query of Handshake Frequency
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Value: 0x2D, no payload
•
This asks for the handshake frequency, response is shown below.
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Message format:
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[0x19][0x00][0x06][0x2D][0x56][0x56]
Handshake Frequency Response
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Value: 0x2E, 1 byte payload
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The handshake frequency number occupies 1 byte in EEPROM in the
SeeLeveL gauge. The frequency can range from 1 to 255 broadcasts
per handshake request. The number is stored in hex from 0x01 to
0xFF.
•
Message format, frequency is 25 (0x19):
•
[0x00][0x19][0x07][0x2E][0x19][0x6C][0x56]
T-DP0301-B Manual
(ELD Master-> SeeLeveL
(SeeLeveL Slave->ELD
Slave)
Master)
Page 13
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