EXAMPLES:
• In the case of a “Sample High” error the Bit 0 (least significant) will be set to one
and all the others to zero, therefore the byte of the Flags will have a 0x01
hexadecimal value and its HEX-ASCII representation will be 0x30 / 0x31.
• In the case of a “Sample Absent” error the Bit 2 will be set to one and all the others
to zero, therefore the byte of the Flags will have a 0x04 hexadecimal value and its
HEX- ASCII representation will be 0x30 / 0x34.
Managing Errors in RESULTS:
If a Test Tube Record is sent with a VES value equal to 0 and an Error Flag enabled (Bit 3
set to 1), the result (VES=0) must be interpreted by the Host as a ‘Reading Error of the
sample’.
RACK ID: Not Used, always “0000” (string of 4 characters without terminator)
POSITION: string of 2 characters without terminator, identifies the position occupied by
the sample into the instrument (“01”…..”04”).
H-CHK / L-CHK: CheckSum of the message, represented in HEX-ASCII. The Checksum is
calculated by carrying out the OR- exclusive of all the bytes sent from STX to ETX
inclusive. The resulting hexadecimal value is then converted into HEX-ASCII and the two
characters that represent it are sent.
ATTENTION: for debugging purposes it is possible to disable the checksum control,
replacing the H-COM bytes with the value of 0x44 instead of 0x35. In this case the two
bytes of the checksum are still sent but their value will be insignificant. The Host
computer must also manage any possible cases in which the checksum is disabled.
Reply from the Host computer (optional)
On receiving the message, the Host computer may send an ACK reply to acknowledge
correct receipt and interpretation of the message, meaning that all the fields have the
correct values, and the checksum is correct; or a NACK reply to indicate that the message
contains one of more errors: inexact checksum, incorrect length of the data field, etc…
ACK Message
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