Calibration for analog sensor (voltage, resistance and NTC sensors)

[ArT]

It is for diesel common-rail engines (fuel pressure various from ~300 bar up to ~2000 bar).

[Daily_Driver]

Why does the UTCOMP factor in the fuel pressure reading? The fuel pressure regulator ensures that the relative pressure in the fuel rail is always the same, so that the fuel delivered per injector pulse is always constant.

I just don't see why the UTCOMP would factor in the rail pressure. It makes no sense - no ECU factors in rail pressure for fuel consumption calculation, so why does UTCOMP?

In my case (larger injectors with an OEM ECU), I have a rising rate fuel pressure regulator. As boost increases, so does the pressure, and it goes above the 1:1 of the OEM regulator. The higher pressure results in more fuel flow. Conversely, I have to turn down the base pressure to less than half of OEM (22 vs 55 PSI) to attain OEM flow rates.

Again in my case, being able to log the fuel pressure as well as boost and RPM will help me to tune the rising rate regulator.

[Daily_Driver]

I have received my device and have completed wiring it. I have a question about the NTC oil temperature sensor. On my spreadsheet, I cannot get accuracy closer than +/- 5 degrees over the range of 50-150C (122-302F). My sensor ohm range is 992 (50) to 48.1 (150), and for 5.2V using A=130 t=1.02 T0=42 I'm off by -4 @ 50, +5 @ 70, and then +9 @ 150. The closest it gets is +1 @ 90. I have input a lot of different values and can't get as close as I'd like.

I'm not a spreadsheet expert. Are there any tips for making the curve closer to my thermistor? It seems like there should be some type of formula to calculate optimum values for all three.

[ArT]

Could you share all resistance table? 992 - 48 ohm for ~100C it is ~950ohm difference and it is very low range. For example, this oil temperature sensor has ~17000 ohm difference for this range (with higher value in range you can get better accuracy).

There is also "Origin" software which can calculate these 3 parameters. Please share your resistance/temperature table.

[Daily_Driver]

Here's the entire table

Code: Select all

C        F     Resistance
-40	-40	102,122
-35	-31	73,340
-30	-22	53,249
-25	-13	39,064
-20	-4	28,939
-15	5	21,637
-10	14	16,321
-5	23	12,413
0	32	9,516
5	41	7,354
10	50	5,728
15	59	4,496
20	68	3,555
25	77	2,830
30	86	2,268
35	95	1,828
40	104	1,483
45	113	1,210
50	122	992
55	131	819
60	140	679
65	149	566
70	158	475
75	167	400
80	176	338
85	185	287
90	194	244.8
95	203	209.7
100	212	180.3
105	221	155.6
110	230	134.7
115	239	117.1
120	248	102.2
125	257	89.4
130	266	78.5
135	275	69.1
140	284	61.1
145	293	54.1
150	302	48.1

[ArT]

It will be quite hard to scale it for low value temperatures because this sensor has typical NTC characteristic above ~60C
I assume that you need it for oil temperature, so I scaled it for 80C range (from 65C to 145C)
A = 120 t=0,77 T0 = 58

please take a look at error column:

ntc-daily_driver.jpg (132.83 KiB) Viewed 82378 times

Your values are also not bad - it will be less accurate for crytical values but you have scaled it for wider range.

ntc-daily_driver2.jpg (126.76 KiB) Viewed 82378 times

Excel in attachment.

NTC_daily_driver.xls

(71 KiB) Downloaded 1638 times

At the moment I do not have access to origin software but I'll check it on origin as soon as I'll have access to this software.

[Daily_Driver]

Thank you for the info ArT. I have downloaded the trial version and know nothing about using it. I'm trying to see if the proper thing to use is a "Non-linear curve fit" tool.

If I figure out what to do, I'll post here for future reference.

[ArT]

Updated UTCOMP calculators for v3.5 version (UTCOMP update soon)
NTC calibration is now simplified.

Please note that all above posts & questions are for older calculator (<= v3.4)

[tmckeown]

Hi,

Has anyone installed autometer gauges and calibrated Reveltronics to those sensors?
I have connected reveltronics to my automater water temperature gauge and gauge shows 80 degrees celsius when I put ignition on.
It is connected to advcc port

Timo

Psi
0 = 250 ohms
25 = 158 ohms
50 = 111 ohms
75 = 75 ohms
100 = 43 ohms

Temperature
38 C = 1123 ohms
49 C = 708
66 C = 374
88 C = 175
100 C = 119
120 C = 65

[ArT]

Is it connected only to UTCOMP AdcVccX ports?
Or is it connected also to other gauge?