Adding formula's to vaiables in Analysis

[Jimster]

I've got my sensors sesors setup and working with my dash2, but I can't remember the values for the sensor which I'm using. The formula it created is this


what is the syntax to use the same formula in RT Analysis?

Thanks

Jim

[pault]

It would look something like

83.59 * VAR_02XX * VAR_02XX + 123.93 * VAR_02XX

where VAR_02XX is the correct variable number for your oil pressure input.

Paul

[Jimster]

Thanks Paul, but I still can get it working, I've tried the following but getting an error:

83.59 * analog 18 * ananlog 18 + 123.93 * analog 18

83.59 * OilPressure * aOilPressure + 123.93 * OilPressure

The sensor is connected to Analog 18, which I have renames OilPressure.

[pault]

The analog 18 input in a user equation is called VAR_0217. You can select it from the Variable list that is on the bottom, right of the equation editor window. In either case, your equation should look like

83.59 * VAR_0217 * VAR_0217 + 123.93 * VAR_0217

I cut and pasted the above equation into the equation editor and it accepts it. I'm using version 7.3.24 of the analysis tool.

Paul

[Jimster]

Thanks for you help paul, I'm now able to add that formula, but if I look at the oil pressure in the values table it reads around 7000psi, strange as it's perfect on my dash2 reading around 50 - 60psi

[pault]

Well it sounds like there may be another math step needed to make it work in analysis. I don't have have a dash 2, so I've never looked through its documentation or anything about how they connect together.

When I get a chance over the next couple of days, I'll see if there is something in the documentation to help explain the differences.

Paul

[faraday]

What does Analysis say if you just leave the sensor type as volts

[Jimster]

If I leave it as volts I get around 0.34 volts

[tristancliffe]

83.59 * 0.34^2 + 123.93 * 0.34 = 51.7

Use brackets so that the calculation is done in the right order.

(83.59 * VAR_0217 * VAR_0217) + (123.93 * VAR_0217)

That should work.

If in doubt with equations always ALWAYS do it manually to see where the problem is. It takes seconds to type 0.34 * 0.34 * 83.59 into a calculator.

[Jimster]

Magic!!! works like a dream now.

Thanks for all your help guys.

[pault]

Thanks for finding the proper solution and pointing out a "flaw" in the way the user variables are calculated. It looks like they are sequential and don't use the standard precedence (do multiplies before adds).

Paul