Inficon SQC-310

4 - 10
PN 074-550-P1C
SQC-310 Operating Manual
4.2.1 Command Packet (Host to SQC-310 Message)
<Sync character> <Length character> <Message> <CRC1><CRC2>
Sync. . . . . . . . . . . . . . . . . . . . . . . . . The Sync character is an exclamation point
(!). Any time this character is received, the
communications for that packet is reset. The
Sync character is not included in the CRC
calculation.
Length . . . . . . . . . . . . . . . . . . . . . . . This is the decimal number of characters in
the packet (excluding the Sync, Length, and
CRC characters). This character has a
decimal 34 added to it so there cannot
accidentally be a Sync character (!)
embedded in the packet.
Message . . . . . . . . . . . . . . . . . . . . . Command as detailed in section 4.3 on page
4-13.
CRC . . . . . . . . . . . . . . . . . . . . . . . . . Cyclic Redundancy Check (CRC) is a
method to verify there are no errors in the
packet (see section 4.2.3 on page 4-12 for
detailed instructions to calculate the CRC
and section 4.4 on page 4-34 for code
examples).
NOTE: If CRC checking in the application is not necessary, send two Null
characters (CHR$0) for the CRC. SQC-310 will ignore the CRC. SQC-310
will still return a CRC in its response, but it can be ignored.