Omron SYSMAC CJ1W-PRM21, Руководство по эксплуатации

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Command / Response Reference
Section 5-2
Note With the message service, there is no guarantee that a message to a destina-
tion node will reach its destination. It is always possible that the message may
be lost in transit due to noise or some other condition. When using the mes-
sage service, it is advisable to prevent this situation from occurring by per-
forming resent processing at the node where instructions are issued. With the
CMND instruction, resent processing is performed automatically once the
number of retries has been set, so be sure to specify a number other than “0”
for the number of retries.
5-2 Command / Response Reference
This section describes the FINS commands that can be sent to the PROFI-
BUS-DP Master Units and the responses to each command.
The command, response, and (where applicable) the results storage blocks
are given with the commands in graphic form as shown in the following dia-
gram. If the data is fixed, it is included in the blocks. If the data is variable, it is
described following the blocks. Each box represents 1 byte; two boxes repre-
sent 1 word. The following diagram shows 2 bytes, or 1 word.
Response codes applicable to the command are described at the end of the
command description.
5-2-1 MEMORY AREA READ (0101)
The MEMORY AREA READ command is used to the last diagnostics data
message the PROFIBUS-DP Master Unit received from the specified slave
station. The command frame requires three byte data type specifier, specify-
ing the information, and one byte specifying the slave station address.
The number of items to read must be 244 - the maximum data size of the
PROFIBUS-DP diagnostics message - or less.
Command Format
Response Format
Two bytes
Slave station address
No. of items
(binary)
Command
code
01 01
Data specifier
FF 81 00
End code Command
code
01 01
Diagnostics data
(for number of items)