Knock channel.
0 means sensor 1 for all cylinders
255 means sensor 2 for all cylinders.
If you need to combine the sensors-events it is more tricky:
0 comes from 00000000 binary
255 comes from 11111111 binary
So if you want to use sensors accordantly to cylinders (spark events) , then for example
10101010 (170) will switch sensor for every spark event.
1 at the beginning belong to bottom cylinder in ignition output table (non used one if it is not 8cyl engine).
0 at the end belong to top cylinder in same table (used always).
any desired combination except 11110000 (240) and 11110001 (241) can be used. These two disables knock.
Converting binary<-> decimal can be done by windows native calculator.
You can read it in different "language" in 1.1.26 description here:
http://www.vems.hu/wiki/index.php?page=GenBoard%2FUnderDevelopment%2FFirmwareChangesOf course you have to be sure about hardware present inside ECU for second sensor.
Gints