Graseby 3000/500, Руководство пользователя

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Graseby Medical L t d Volumetric Infusion Pumps
12 - 10 Issue 1(April 2002) 3000/3100 and 500/505 Service Manual
Command Record Format - version 0.68 and above
A command record consists of a string of characters sent from a host to
the pump that are in a specific order and follow the rules listed here.
The general format can be summarized as follows:
< LLCDDDXXXX >
where:
< = record header 1 character
LL = record length 2 characters
C = command code 1 character
DDD = command parameters variable length - 0 to 17
characters
XXXX = record CRC 4 characters
> = record terminator 1 character
Total - 9 to 26 characters
Record Header
As shown above, the first character of any record transmitted will be
an ASCII "<" character (3C hex). This character will be recognized as
the start of a new record upon any occurrence. Therefore, this
character should not appear anywhere within the record, other than as
the record header. Should this character appear within the record, the
partially assembled record will be discarded and an attempt will be
made to begin assembling a new record. The pump will not respond to
a partially assembled record. See the section entitled 'Return Record
Format' for information regarding when a return record will be sent.
Record Length
The second and third characters are made up of the ASCII digits 0-9
and letters A-F, a-f. This two digit string, with the most significant
digit in the second character position of the record, represents the
total character count of the record being transmitted. The two digits
form a hexadecimal value representing an 8 bit number. The count
includes the header, record length digits, command code, command
parameters, CRC characters and terminator. A minimum record will
have no parameters; therefore, the minimum record length is 9
characters. Maximum allowed parameter length is 17, so the maximum
allowed record length is 26 (1A in hexadecimal). When a message is
received that is too short, too long, or the record length does not equal
LL, the pump will send a ‘return record’ indicating the problem. See
the section entitled 'Return Record Format' for information regarding
return records.
Command Code
The fourth character in any record shall be the command code, which
is transmitted by the host to the pump to tell the pump what
information or action it wishes. Command codes are ASCII letters,
case sensitive. When the pump receives a character which is not one of
the supported commands specified below, the pump will indicate
‘Invalid Command Code’ in the ‘return code field.’