Mitsubishi Electric QJ71E71-100 User Manual page 124

(b) When "Fixed Length/Variable Length" is "Variable Length"
An area starting from the device number which is specified in the "Element Setting" window +1 is considered as
the data storage area.
The data storage area to be occupied varies depending on the setting of "Unit of Stored Data".
• When "Lower Byte + Upper Byte" is selected, the same size as the data length + one word (length for the
data length storage area) are occupied. (However, when the data length of a send packet is an odd
number, the upper byte (lower byte for "Byte Swap") of the last device is not sent. When the data length of
a receive packet is an odd number, the last data is stored with one byte of 00
• When "Lower Bytes Only" is selected, twice size of the data length + one word (length for the data length
storage area) are occupied.
Specified device
(Word)
+ 0
Data length storage area*
+ 1
Data storage area
+ n
*: The unit of the data length is fixed to byte.
● Multiple Non-conversion Variable elements can be placed in a packet.
● When "Fixed Length/Variable Length" is "Variable Length" and the configuration is set as follows, an error occurs:
• An element other than Static Data is placed behind a Non-conversion Variable element when Non-conversion
Variable is out of the Length calculating range or when there is no Length element (except for when Non-
conversion Variable is placed at the end of the packet elements).
• Multiple Non-conversion Variable elements are placed in the Length calculating range, while a Length element is
not placed.
• A Non-conversion Variable element is placed before a Length element in the Length calculating range.
122
Send
packet
Send packet: The user stores the send data.
Receive packet: The E71 stores the receive data.
Receive
packet
.)
H
Data storage area
Data storage area