1078
Network Instructions Section 3-25
Precautions Be sure that the order of bytes in the source data matches the order in the
explicit message’s frame (order of data in the line). For example, when the
service data is in 2-byte or 4-byte units, the order of data in the frame is left-
most to rightmost order in 2-digit pairs, as shown in the following diagram.
The following diagrams show how data is stored in the data areas when the
service data is in 2-byte or 4-byte units.
1. Data in 2-byte Units
• Storing Data from the Leftmost Byte (Bits 12 to 15 of C = 0 hex)
Example: Storing the value 1234 hex in D+1
Communications
Port Error Flag
A21900 to
A21907
These flags are turned ON to indicate that the
explicit message itself was not sent from the cor-
responding ports (00 to 07) during execution of
an explicit message instruction.
The flag status is retained until the next network
instruction is executed. The flag will be turned
OFF when the next instruction is executed even if
an error occurred previously.
Communications
Port Completion
Codes
A203 to
A210
These words contain the completion codes for the
corresponding ports (00 to 07) following execu-
tion of a network instruction.
The corresponding word will contain 0000
while the Explicit Communications Error Flag
is OFF.
The corresponding word will contain a FINS
error code when that port’s Explicit Communi-
cations Error Flag and Communications Port
Error Flag are both ON.
The corresponding word will contain the
appropriate explicit message error code when
that port’s Explicit Communications Error Flag
is ON and the Communications Port Error
Flag is OFF.
The corresponding word will contain 0000 while
the network instruction is being executed and the
completion code will be written when the instruc-
tion is completed. These words are cleared when
program execution begins.
Name Address Operation
78 56 34 1234 12
Service Data:12345678HexService Data:1234Hex
Command format
Example: Address 1234 hex
stored in 34 → 12 order
Example: Cumulative time12345678
hex stored in 78 → 56 → 34 → 12 order
34
15
341D+1 2
08 07
00
12
Frame
The data in the frame is
in the order 34 → 12.
In this case, 1234 hex is
stored from the leftmost
byte in the order 34 → 12.
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