LG MASTER-K 120S Series User Manual page 253

Chapter 8 Communication Functions
• S3 format is as below.
bit 15
• NDR : when the communication ends normally, this bit turns on during 1 scan.
• Error bit : when communication error occurs, this bit turns on during 1 scan. At that time error code stores bit 8 ~ bit 15.
• Error code is as follow
Code
01 Illegal Function
02 Illegal Address
03 Illegal Data Value
04 Slave Device Failure
05 Acknowledge
06 Slave Device Busy
07 Time Out
08 Number Error
09 Parameter Error
10 Station Error
Remark
-. In MASTER-K120S series, the 'MODBUS' command which has been used in MK80S series can be used.
In this case, communication channel is fixed to channel 0.
Error code
Error type
Error in inputting function code in instruction.
Error of exceeding the area limit of reading/writing on the slave station.
Error when the data value to be read from or write on the slave station isn't
allowed.
Error status of the slave station.
It's a responding code of the slave station for the master station to prevent the
master station time-out error, when request command processing takes time.
The master station marks an error code and waits for a certain time without
making any second request.
Error when request command processing takes too much time. The master
should request again.
Error when exceeds the time limit of the communication parameter as it
communicates.
Errors when data is 0 or more than 256 bytes
Error of setting parameters (mode, master/ slave)
Error when the station number of itself and the station number set by the
S1 of instruction are the same.
bit 8
Meaning
8-63
bit 1 bit 0
Error bit NDR bit