Mitsubishi MELSEC LJ71C24, User Manual

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9 DATA COMMUNICATION USING THE PREDEFINED PROTOCOL
POINT
To place a Conversion variable in a packet, the following requirements need to be
met.
(1) To place Conversion variable in send packet
Multiple Conversion variable elements can be placed in one packet, and they
can be placed in desired positions in the data division.
(2) To place Conversion variable in receive packet
Multiple Conversion variable elements can be placed in one packet in the
cases other than [Variable Number of Data] and (a) - 1) of [Fixed Number of
Data].
[Variable Number of Data]
Only one Conversion variable can be placed in one packet, and any of the
following 1) and 2) need to be met.
1) For discriminating the data length of a Conversion variable, any of the
following items is placed immediate after the Conversion variable.
Static Data
Terminator
Check code + Static Data
Check code + Terminator
2) A "Length" is placed before a Conversion variable. (The Conversion
variable needs to be included in the calculating range.)
[Fixed number of data]
(a) Variable number of digits
1) When the number of data is 2 or more, or the number of data is 1 with
no delimiter, only one Conversion variable can be placed in a packet and
it needs to be placed in the order mentioned in [Variable number of
data].
2) When a Conversion variable (the number of data is 1, with delimiter, and
variable number of digits) and the following four elements are placed in
the same packet, these four elements need to be placed behind the
Conversion variable (the number of data is 1, with delimiter, and variable
number of digits).
Conversion variable (variable number of data)
Conversion variable (fixed number of data and variable number of digits)
(The case of (a) – 1. Excluding a case where "Number of Data" is '1' and
"Delimiter" is not "No Delimiter".)
Non-conversion variable (variable length)
Non-verified reception (variable number of characters)
Note that two or more of these four elements cannot be placed in the
same packet.
(b) Fixed number of digits (1 to 10)
1) When a Conversion variable (variable decimal point) and the four
elements mentioned in (a) – 2), these elements need to be placed
behind the Conversion variable (variable decimal point).
2) When a Conversion variable (unsigned) and the four elements
mentioned in (a) – 2), these elements need to be placed behind the
Conversion variable (unsigned).