Hey guys.
I am trying to write some rs232 commands for a samsung pro panel. I am having a hard time figuring out the checksum calc. can someone please help?!!!!!
This is what i have so far.
(already Works)
Power on. AA 11 FE 01 01 11
Power Off. AA 11 FE 01 00 10
(Cant figure out the checksum)
Input Comp. AA 14 FE 01 08
Input HDMI AA 14 FE 01 21
This is from the samsung manual.
Every communication will be made in hexadecimals and Checksum is the sum of all
remainings. If it exceeds two digits, for example, it is 11+FF+01+01=112, discard the
number in the first digit like below.
example) Power On & ID=0
Header Command
ID
Data Length Data 1 Check
0xAA 0x11 1 Power Sum
→
Header Command
0xFF
Data Length Data 1
12
0xAA 0x11 1 1
- If you want to control every mechanism connected with Serial Cable regardless of its
ID, set ID part to "0xFE" and send commands. At the time, each SET will follow
commands but it will not respond with ACK.

Add everything in the string except the initial "AA". You can use the Windows calculator in hex mode for this. If the result is more than two digits, the checksum is the right-most two digits.

Ex. Power On - 11+FE+01+01 = 111, the chksum is 11, so the entire string is
AA 11 FE 01 01 11.

Ex. Input Comp - 14+FE+01+08 = 11B, the chksum is 1B, the entire string is
AA 14 FE 01 08 1B.

Does this do the trick?

So what is the checksum for the HDMI command?

Just wanted to say this example helped me immensely.
I'm new to RS232 commands and Samsung's manual wasn't very clear to me on the proper syntax. Thanks!

For anyone working in Crestron's SIMPL Windows, remember that those two above commands would also need to include the escape characters.

Examples:

\xAA\x11\xFE\x01\x01\x11

\xAA\x14\xFE\x01\x08\x1B

I have a question related to this. I also need calculate the checksum for Samsung MDC. My issue is the volume command.

It is formatted as follows:
AA Header
12 Command
01 ID
01 Data Length
(1-100) Data 1(volume level)
?? Checksum

My question is the Data 1 field. Does that number need to be converted to hex? So should I enter 55(dec) or 37(hex)?

If I know that I know how to calculate the checksum.

it should be converted to hex