ACOEM Met One Instruments GAS-1060, User Manual

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Parts List Page 141
Appendix A. Advanced Protocol
The Advanced protocol allows access to the full list of instrument parameters.
A.1 Command Format
All commands and responses sent to and from the Instrument will be in the following packet format
to ensure data is reliable.
Table 13 – Packet Format
1 2 3 4 5 6 … 5+n 6+n 7+n
STX (2) Serial ID Command ETX (3) Message
Length (n) Message Checksum EOT (4)
Where:
<STX> ASCII Start of Text = 0x02 hex.
Serial ID The Serial ID assigned in the Main Menu

Communications Menu

Serial Communication Menu.
<ETX> ASCII End of Text = 0x03 hex.
Checksum The XOR of the individual bytes except for STX, ETX, EOT and
Checksum.
Message length Must be in the range 0 to 32. Responses from the instrument can have
a message Length of 0 to 255.
<EOT> ASCII End of Transmission = 0x04 hex.
Examples
A basic request for Primary gas data would be as follows:
Table 14 – Example: Primary Gas Request
Byte Number 1 2 3 4 5 6 7 8
Description STX ID Command ETX Message
Length Primary Gas
Conc Checksum EOT
Value 2 0 1 3 1 50 50 4
Checksum
Calculation 0 0

1=1 1

1=0 0

50=50
50
And a sample response: