I am trying to figure out how to execute "$SC xx V" RAPI commands, using the correct checksum, so I can properly interpret the response using a script. I am a bit baffled how to calculate this though, and was hoping for some explanation:
$= start of RAPI command
cc = 2-letter command
pp = parameters
xk = 2-hex-digit checksum - 8-bit XOR of all characters before '^'
ss = optional 2-hex-digit sequence id - response will echo the
sequence id - ss CANNOT be 00, which is reserved as an
\r = carriage return = 13d = 0x0D
Checksum + Sequence ID
$cc pp :ss^xk\r
I understand how to structure the body of the command, up until the ^xk\r
Can someone explain, for example, how I would know that the proper flag to attach to this command, from the OpenEVSE documentation, is ^64?
How would I go about figuring out the flag to attach to $SC 12 V or any other current rating?
Thank you very much!
Here is an online calculator.
Enter the full command in the ASCII section including the return for the CheckSum8 Xor.