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Gesytec (Bayern-Hessen) Protocol
Block Checksum Characters <BCC>
Block Checksum
Characters <BCC>
The Block Checksum Characters are calculated beginning with a seed value
of 00000000, binary (0x00), and bitwise exclusive ORing with each of the
characters of the command string (or response) including the framing
characters <STX> and <ETX>. The checksum works as an error check. The
command terminator determines the presence or absence of <BCC>.
If a command is terminated by <ETX> then the next two characters are the
checksum, if the command is terminated with <CR> no checksum is
attached.
The block checksum is represented by two characters, which represent a 2
digit hex number (1byte) (e.g. 1 byte 0xAB hex checksum will be
represented by the two characters ‘A’ & ‘B’).
The checksum is referred to as <BCC> throughout this document.
Gesytec Commands
Instrument Control Command
(ST)
The following commands are supported by the Gesytec protocol:
●
Instrument Control Command (ST)
●
Data Sampling/Data Query Command (DA)
There is one control command supported by the Gesytec protocol.
This <control command> is a single letter, which triggers an action in the
instrument. These commands are active only when service mode is inactive
and the zero/span option is present.
Command ‘N’ initiates a filter change.
The following are the different acceptable formats of the ST command:
<STX>ST<address><control command><ETX><BCC>
OR
<STX>ST<address><control command><CR>
OR
<STX>ST<address><SP><control command><CR>
OR
<STX>ST<address><SP><control command><ETX><BCC>
The <address> is optional, which means it can be left out completely. The
<address>, if present, must match the Instrument Address. Additional space
can be present after the <address>.
Thermo Fisher Scientific
Model 5030i SHARP Instruction Manual
D-3