jeff48

Here is a copy of what I sent to Howard. We have both had success with using this process.

What I finally did to get reliable figures was to compare the voltage outputs from my amplifier outputs (the 10V as read by a DVOM and the 5V as reported by FC Edit).

First I hooked up the 5V (post divider) outputs (front and rear housing) to the datalogit at AN3 and AN4. I set the datalogit AN3 and AN4 outputs to simply read voltage so I entered 0=0 volts and 5=5 volts in the boxes.

I then hooked up one of the 0-10 Volt outputs to the + side of a DVOM and the - probe got attached to a chassis ground. I set the DVOM to measure Volts DC. 1 volt DC = 100 degrees C. So looking at the DVOM and seeing 5.8 Volts you are seeing 580 degrees C---9.10 Volts=910 degrees C.

Open a Watch in FC Edit to show the volts as reported by AN3 or AN4---whichever one corresponds to the 0-10V output hooked to the DVOM. Now start a log so that the Watch Box will start reporting the Voltage seen by the datalogit. It WILL be lower than you expect by a bunch.

Now go for a drive with a friend. Have the friend record the DVOM readings and the voltage readings from the datalogit at idle. Now drive along until you can stabilize the DVOM reading at another point--say 600 degrees C and then have the friend record the Volatge reported by the datalogit. Do this over and over for as many points as you like but trying to get representative samples from all along the temperature range.

Repeat the process for the other housing and AN#.

You will have a chart of points similar to the following

Front Rotor----------------------------------Rear Rotor
DVOM------Volts FC Edit------------DVOM------ Volts FC Edit
300-----------1.3-----------------------300------------1.22
400-----------2.1-----------------------400------------2.23
500-----------2.45----------------------500------------2.38
600-----------2.89----------------------600------------2.82
700-----------2.93
800 And so on
900
1000


You can then check for linearity by entering the data into a spreadsheet and making sure you still have a linear relationship between the DVOM (which is entirely accurate) and the Datalogit readings (which are corrupted by the datalogit circuitry). If they are linear (like mine) you will not need a polynomial. If they are not, have Excel generate a polynomial.

Return to FC Edit and go to AN3 change the output from Volts to degrees C and name it Front or Rear Rotor EGT. Now enter the lowest reading in the "0 volts" box and across from it enter the temperature that corresponds to it from the DVOM/0-5V chart you made. Next enter the highest reading in the "5 volts" box and across from it enter the temp that corresponds to it. If you have to use a polynomial do so now (same as we do with the TE AFR unit).

Repeat the process for the remaining Rotor.

You now have an accuratized output system that is totally set for your system.

Hope this helps. If anything is unclear, you know you can PM


Cheers
Jeff

GQMRacerX7

Thanks Jeff. I appreciate your help. I used a camera with my DMM set next to the computer to get my points. Worked great although I'm not too sure when I was on-boost that it was that safe... I attached one of the pics for the fun of it.

jeff48

That is a fantastic shot of the DVOM and computer. I wish I had been that smart....Note to others....The camera thing is the way to go.

BTW that 2.91v = 791 degrees C is real close to mine (a little over 800 on mine).

Datalogits seem to really screw up input voltages badly. 2.91v should be 582 degrees C, if all things were correct with the DL..... They should think about fixing those problems or disclosing the problems and the fixes if they are going to keep offering the AN connections.