Math channels

A math channel is a named formula over the channels in the log. Once defined it behaves like a logged channel: it graphs, it drives a gauge, it fills histogram cells and it can be binned on an axis.

Common ones: Total Fuel Trim 1 = [Short Term Fuel Trim Bank 1] + [Long Term Fuel Trim Bank 1], lambda error as a percentage, converter slip, a corrected load.

• Reference a channel in square brackets: [Engine RPM]. Names match ignoring case and spacing, and a bare multi-word name gets bracketed for you when you commit it.
• Roles work too, so [engine_rpm] resolves on any log that has one.
• Arithmetic is + − * / ^ with brackets.
• The Functions list in the editor shows everything available, with what each argument means. Window functions such as an average over time take their window in milliseconds.
• One math channel can reference another by name. A loop is detected and reported rather than hanging.

The line under the box tells you whether the expression is valid as you type, and where the problem is when it is not.

Open it from the histogram list menu: Manage math channels…. Each channel has a name, an expression and a unit, and the unit is inferred from the channels you used if you leave it blank.