Shinko BCR2 - Page 8

8
(5) Negative acknowledgement
Header
(15H)
Address
Error
code
Checksum
Delimiter
(03H)
1 1 1 2 1
Header: Control code to represent the beginning of the command or the response.
ASCII is used.
Write command, Read command: STX (02H) fixed
Response with data, Acknowledgement: ACK (06H) fixed
Negative acknowledgement: NAK (15H) fixed
Instrument number (Address): Numbers by which the master discerns each slave.
Instrument number 0 to 94 and Global address 95.
ASCII (20H to 7FH) is used by adding 20H to instrument numbers 0 to 95 (00H to 5FH).
95 (7FH) is called Global address, which is used when the same command is sent to
all the slaves connected. However, the response is not returned.
Sub address: 20H fixed
Command type: Code to discern Write command and Read command.
Command
Type
Contents Description
20H Read a single piece of data Reads a single piece of data.
24H Read multiple pieces of data Reads consecutive multiple pieces
of data. (Amount of data: Max. 100)
50H Write a single piece of data Writes a single piece of data.
54H Write multiple pieces of data Writes consecutive multiple pieces
of data. (Amount of data: Max. 100)
Notes about Reading/Writing multiple pieces of data
When reading/writing multiple pieces of data, as it takes time until slave sends response
data, the master determines no response time based on timeout period below after
sending a command.
Timeout period calculation: 6 ms x Amount of data + Response delay time (*)
(*) Refer to Response delay time on p.5.
Data item: Classification of the command object.
Composed of 4-digit hexadecimal numbers, using ASCII.
Refer to ‘7. Communication Command Table’. (pp. 26 to 40)
Data: The contents of data (values) differ depending on the Write command.
Composed of 4-digit hexadecimal numbers, using ASCII.
Refer to ‘7. Communication Command Table’. (pp. 26 to 40)
Checksum: 2-character data to detect communication errors.
Refer to 5.3 Checksum Calculation on p.9.
Delimiter: Control code to represent the end of command.
ASCII code ETX (03H) fixed
Error code: Represents an error type using ASCII.
Error Code Contents
1 (31H) Non-existent command
2 (32H) Not used
3 (33H) Value outside the setting range
4 (34H) Status unable to be written (e.g. AT is performing.)
5 (35H) During setting mode by keypad operation