Pioneer 504CMX - PDP - 50" Plasma Panel Command Reference Manual page 17

RS-232C Adjustment Mode
Check Sum
This is data to which 2-Byte ASCII code is added to a data group returned by a GET command.
PC side
STX ID GET command
02 (hex) 2 Byte 3 Byte
A detailed example will be given below.
Example: The Check Sum value that is added when the GET command GAA returned the following 6-Byte data.
Data group (ASCII)
+ check sum
The data group is put in to binary code one
character at a time and displayed (only the
last two digits are displayed)
Note: The returned data group will be in capital letters. Please keep this in mind when introducing it into the binary display.
Example of Check Sum applications
Example 1: when the data is missing one Byte
STX GET command
02 (hex)
47 41 41
The data group is calculated according to the rules by a PC application and
when these values are added the result is 1C4 (hex).
Here, the check sum [F5 (hex)] and the calculated [C4 (hex)] do not match.
Since they do not match, the PC application sends the GET command again and gets the data again.
Example 2: when one Byte of data is unreadable
STX GET command
02 (hex)
47 41 41
The data group is calculated according to the rules by a PC application and
when these values are added the result is 1F7 (hex).
Here, the check sum [F5 (hex)] and the calculated [F7 (hex)] do not match.
Since they do not match, the PC application sends the GET command again and gets the data again.
15
ETX
03 (hex)
Set side
STX
02 (hex)
GET command
GAA
47 41
When these values are added the result is 1F8 (hex)
As the data format, F5 is converted to ASCII code and sent.
The following data is output from the plasma display side.
GET command
STX
02 (hex)
Data (6 Byte)
(missing data)
GAA 100
31 30 30 32
Data (6 Byte)
GAA 100328
31 30 33 30
GET command
3 Byte
Data (6 Byte)
100128
41 31 30 30 31
Data
GAA 100 (missing data)
Check Sum
28 F5
38
Check Sum
F5
32 38
Data Check Sum
*Byte 2 Byte
Check Sum
xx
(before calculation)
32 38
Check Sum
ETX
28 F5 03 (hex)
ETX
03 (hex)
ETX
03 (hex)
ETX
03 (hex)