Chapter 8 Communication Functions
8-63
• S3 format is as below.
bit 15 bit 8 bit 1 bit 0
• 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 Error type Meaning
01 Illegal Function Error in inputting function code in instruction.
02 Illegal Address Error of exceeding the area limit of reading/writing on the slave station.
03 Illegal Data Value Error when the data value to be read from or write on the slave station isn’t
allowed.
04 Slave Device Failure Error status of the slave station.
05 Acknowledge
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.
06 Slave Device Busy Error when request command processing takes too much time. The master
should request again.
07 Time Out Error when exceeds the time limit of the communication parameter as it
communicates.
08 Number Error Errors when data is 0 or more than 256 bytes
09 Parameter Error Error of setting parameters (mode, master/ slave)
10 Station Error Error when the station number of itself and the station number set by the
S1 of instruction are the same.
Error bit NDR bit
Error code
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.