i3TOUCH Excellence, Руководство пользователя

Страница: 13 / 20

13
3-6-3 Data structure
Note: All numbers shown are in the protocol description are in string unless indicated otherwise.
Percentages are shown in decimal.
General Command Form
• STX. The first character is the standard Start of Text (STX) character ‘S’.
• Address. The second character is the device address.
If a device does not support addressing, these should be 0 and 9 to act as the global address.
• Type. The third character is the command type.
There are four types of commands:
o Command 0
o Ack 1
o Nak 2 (option)
o Notification 3 (option)
• Property ID.
The four and fifth and characters are the property identifier. By using one byte we have 256
• Data Length.
The sixth character is the number of characters in the parameter data section.
• Data.
Following the sixth character is the parameter data section that is as many characters long as the sixth character
indicates. If the sixth character is 00 (as with the Reset command for example) then there are no characters in the
parameter section. This parameter section contains the value (hexadecimal ) for the property.
• ETX.
The last character is the standard End of Text (ETX) ‘EN’.
Sample:
In this example (Power On to everything), the Address character 0, which is the global address for all devices connected to
the serial port. The Type character is 0 to indicate the transmission is a command.
The Property ID characters indicate a property identifier of 1, which in this protocol is the value for power.
The Length character is a 1, which indicates that there is one character of data associated with this command.
The Data has a value of 1, which is the value for ON. The ETX is command End code.