Page 1 of 1

Adding an oil temp gauge

Posted: Mon Jan 16, 2012 5:35 pm
by Shotgun
I had an oil temp sensor all set up on my rotary engine, but I had it plugged into the end of a dual remote oil filter mount. It was not in the oil flow. Sat back in sort of an alcove. So I decided to move to were I could trust the reading. I used a stock MAT sensor in the aluminum block that I used to cover the stock oil filter mount, where oil will flow on both sides of the sensor.

Since I switched to a different sensor, I have to change the oilTemp.inc file to reflect appropriate new values. This ain't easy.

To help others seeking this information (and to provide a place for me to find it the next time I need it 8*), here is what I have.

Make the hardware modification as documented in the article for adding an oil pressure sensor. I used a 2.2Kohm bias resistor.

In my mainController.ini, at or around line 2752, I added the following line after the line defining the matGauge.
oilTGauge = OilTemp, "Oil Temp", "°F", -20, 230, -20, 40, 190, 200, 0, 0

Along about line 3185, between the definition of altDiv2 and cycleTime1, I added the line
OilTemp = { table(adc7, "oiltemp.inc") }, "°F"

In the [Datalog] section, after the entry for coolant, on about line 3276, I added the line
OilTemp = { table(adc7, "oiltemp.inc") }, "°F"

At this point, TS should log and display on a gauge the value from oiltemp.inc that corresponds to the ADC value seen on adc7. The only issue at this point is generating an appropriate oiltemp.inc file.

I measure three temps and resistances: 207.5*F/183.3ohm, 75.2*F/2.05kohm, and 21.2*F/12.19kohm, and as stated, I have a 2.2kohm bias resistor. I tried using Mike Soultanian's VB script which was uploaded to this forum. I had to modify it to only output ADC vs display values. With MAT, CLT and the wall thermometer all saying the temps are in the mid 50s, the oil temp is saying -1*F.

I generated values with a spreadsheet called Steinhart_Hart.ods that I downloaded from somewhere. The values it generates tells me that the oil is 140*F. It's been sitting in that 50*F garage for months now. So that ain't right either.

How can I reliably generate an oilTemp.inc file when I know what the parameters are?

Re: Adding an oil temp gauge

Posted: Mon Jan 16, 2012 5:49 pm
by Shotgun
Well, ..... , crap-a-doodle.

Immediately after posting the previous, I looked at the values I had input to the VBS script. I had put 7.2 in instead of the 75.2 for the middle temp/resistance reading.

GIGO.

Corrected the mistake. Generated a new table, and ...BAM!... it reads exactly the same as the MAT gauge. 54*F.

The modification I made to Mike Soultanian's generatectlfactor.vbs script was that I change line 97 to read:

objFile.WriteLine adcCount & vbTab & Round(Tu(tt/10.0, blnDegressInCelsius),1)

I copied the output cltfactor.inc file over the oilTemp.inc file in my configuration directory, then deleted the header and footer, leaving only the ADC vs temp values.