Burkert Type 8056 - Manual (Page 69)

- 69 - RS232_485_ETP_MODBUS_BU_REV02.doc
General input syntax. The information are entered in the flow meter as text line strings, with one or more
command-sequences terminated by the <CR> character. The command-sequences are executed in the
same order as they are found in the string. The execution of the commands contained in the input string
does not start until the <CR> character is received. The optional <LF> character that may follows the <CR>
is not considered but it is accepted because usually the Hyper-Terminal or similar application sends also
this extra character when the <CR> is sent.
As a rule, an input string is composed of one or more command-sequences, terminated by the <CR>
character and an optional <LF> character.
The command-sequence is composed by the following elements, exactly in this order:
• A five-letter mnemonic command, always present
• An
operator, always present
• An
optional value, present only when requested by the operator type
• An
optional comment-separator, may be present if it is also present the value
• A
comment, present only if it is also present the comment-separator
• An
optional command-separator, present only if another command-sequence follows it
With the exception of the comment element, no other extra characters or spaces are allowed in the
command-sequence.
Command. The commands are always represented by a five-letters mnemonic code and are case
insensitive, so for example the command MODSV can be written “MODSV”, “Modsv”, “modsv”, “mOdSv”
and in any combination of upper / lower case letters.
Operator. The operators permit to choose one of the three possible functions associated to the command
at which they are attached and they are:
• READ, indicated by the ? symbol. It is used to read values.
• SET, indicated by the = symbol. It is used to set values.
• HELP, indicated by the =? sequence of symbols. It is used to display a set of options or a range of
permissible values related to the command.
Value. The values can be numbers, strings or special formatted fields like the date / time or the IP
addresses, depending on what it is expected by the command. Numeric values are always checked for
validity range and strings are checked for length. IP addresses and date / time fields are checked only for
the correct syntax but not for the values, so please be careful, because in case of misspelled characters or
wrong numeric values the result may be different from what it is expected. In case of floating-point
numbers, the decimal point symbol to be used is the dot (.), not the comma (,).
Comment-separator. This is an optional element and it is indicated by the : symbol.
Comment. This element may be present only when the value to input belongs to a list of options,
composed by numbers and descriptions. Normally the user doesn’t have to supply both, but in case of
copying and pasting some values coming from a previously listed configuration, this ensures the full
compatibility between the output and the input formats.
Command-separator. This element is required when more than one command-sequence is submitted in
an input string and it is indicated with the , symbol.
For each command-sequence recognized and executed, the flow meter returns one of the following output
types, depending on it:
• a
result code, when a function execution was requested
• an
expression, when a parameter or a process data value was requested
• a
list of options or a range of values, when an help on a parameter was requested