REVELTRONICS

hello everybody,

I installed an Utcomp-pro in my Volvo XC70 and use 2 NTC sensors to read oil and manifold air temperature. for some reasons these sensors never read temperatures below 30 degrees. when I enter in the car in the morning and the OEM car temperature sensor(outside temperature on instrument panel) read 8-9 °C the 2 NTC read 30°C while a couple of DS18B20 I connected to the instrument read exactly the same temperature as the car OEM sensor. the sensor sheet contains 2 possible calibration data: the first is for 60-150 °C and another for 50-120 °C. I do not understand if these 2 different calibration data are intended for 2 different kind of sensors and which is mine but tried both and the difference is small. I wonder if these NTC sensors are designed in such a way that they cannot read temperature below a certain value or I am using a wrong setup. can somebody advice me?

There was two calibration methods in UTCOMP's:
1. with 3 parameters A, t and T0
2. with 2 parameters with R25 and Beta

First method cna show only correct values above 60C (or above 50C if you limit your upper range)
Second method can show correct values almost in full range.

I guess you are using first method. If you have firmware 3.x you can update to latest version and use second method (with R25 and Beta)

thank you Art for your support, I now see where the problem is. I have firmware 3.4.0 and the NTC data sheet I have suggests only the first calibration method: I am currently using A -1.0 t -1.1 TO 141,3. where can I find the right parameters for R25 and Beta?

Here you have: https://www.reveltronics.com/downloads/ ... sorNpt.pdf
R25 = 47000 Beta = 3800

I ran the new firmware and setted the device to the new calibration you provided. now it works fine! thanks Art!
by the way, I installed a MAP bosch sensor: the sensor sheet gives 2 possible calibrations
a 0,66 b -0.06 absolute air pressure
a 0.66 b -1.06 boost only
I tried both calibrations but for some reasons the device goes to full-scale as soon as you give a small amount of throttle. may be there is a newer/different calibration for this sensor also?

Calibration for MAP is fine. If it goes to max value it means UTCOMP reads maximum voltage on input, seems something wrong with connections. MAP has 3 pins, one is ground, one is power supply (+5V) and one is output signal which should be connected to AdcX input. Please check these connections.

today I installed a second pressure instrument to check what the Utcomp is reading and found out that all values are correct: MAP has a top pressure of more than 3 bar. unfortunately the bosch sensor I installed has a top value of 2 bar that is why it goes so often to full scale. it is listed as a 0.2-3 bar but since it shows atmospheric pressure at 0,9(when the engine is not running) I calibrated it at A=0.66 and B=-0.96 so it can read 0 to 2.1 bar. Art can you provide me with a different sensor capable of more then 3 bar?

In such case you will need >4 bar MAP. Unfortunately we do not have such sensors in offer at the moment. I was looking bosch MAP 4bar but all available sensors were with plugin connection to manifold (without external pipe).

I can build an adapter to install the sensor just like it was bolted on a OEM pipe but with a plug for the external gummy pipe but how to calibrate that kind of sensor?

2 options:
1. find datasheet for sensor
2. scale it using external meter (you will need voltage/pressure for min/max range - it will be linear output)