Fuji Electric ZKM, Руководство по обслуживанию

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INZ-TN5A0506-E
5.3 Response of Slave Station
(1) Response for normal command
To a relevant message, the slave station creates and sends back a response message which corresponds to
the command message. The composition of message in this case is the same as in Section 5.2.
Contents of the data field depend on the function code. For details, refer to chapter 6.
(2) Response for abnormal command
If there are problems (such as specification of a nonexistent function code) with the contents of the
command message other than transmission error, the slave creates and replies with an error response
message without following the command.
The composition of response message at error detection is as shown in Fig. 5-2 the value used for function
code field is function code of command message plus 80
H
.
Table 5-1 gives error codes.
Station No. (1 byte)
Function code + 80
H
(1 byte)
Error code (1 byte)
Error check code (CRC-16) (2 bytes)
Fig. 5-2 Response message at error detection
Table 5-1 Error Code
Error code Contents Explanation
01
H
Illegal function code Non-actual function code is designated.
Check for the function code.
02
H
Faulty address for coil or register A relative address of a coil number or resister
number to which the designated function
code can not be used.
03
H
Illegal data value Because the designation of number is too
much, the area where resister numbers do not
exist is designated.
(3) No response
Under any of the following items, the slave station takes no action of the command message and sends
back no response.
• A station number transmitted in the command message differs from the station number specified to
the slave station.
• An error check code is not matched, or a transmission error (parity error, etc.) is detected.
• The time interval between the composition data of the message becomes longer than the time
corresponding to 24 bits. (Refer to Section 5.6 Transmission Control Procedure)