filth

Hi,

im trying to figure out how to connect a 0-10 Bar VDO Oil pressure sensor.
I have created a new sensor in race studio 3 and entered its values:

Bar -- Ohm
0 10
0,5 21
1 31
1,5 42
2 52
3 71
4 90
5 107
6 124
7 140
8 156
8,5 163
9 170
10 184

Race studio suggested me to use 2700 Ohm pull up. So i connected the Signal from the VDO Sensor to Analogue In 1 and put VRef with a 2.7k Ohm resistor to the signal line.

Doesnt seem to work. Am i missing something essential?

Thanks

Matt Romanowski

Is this an AiM VDO sensor or one you supplied? The AiM sensor is in the included sensor list and the harness with it has the resistor built in.

filth

Its my own sensor, so no built in resistor there.

So what i did is:
Connect signal line from VDO Sensor to Analog In 1
VRef with a 2.7k Pullup to the Signal line.
Created Sensor in Race Studio (Input Type Ohm, Calibration Type: none -- what does it mean btw?)
Analog GND to chassis GND

Do i need to connect one of the GND lines from the bigger connector (its a mxs strada) to chassis GND as well?

When i go to live measures, live studio always shows a reading of 5v for that sensor.

Matt Romanowski

The analog ground goes to the second VDO wire, not the chassis. If you put it to the chassis, it will always read 5 volts because there is complete resistance (signal to vref).

I haven't seen a MSX Strada harness, but assuming it's like the MXL2, MXS, MXG, it has a ground for the dash and another for the k line. The dash is the only one that has to be hooked up.

Here's how AiM does it http://www.aim-sportline.com/downloa...DO_104_eng.pdf

filth

There is no second VDO Wire. The sensor has only 1 Output wire, which is the variable Resistance

filth

Ok i fixed it, so im getting around 3 bar with engine running but -0.7bar with engine stopped. i guess there is something like a calibration needed? Can you explain how the calibration buttons in race studio work?

Matt Romanowski

There is no calibration for that sensor. The calibration is for a rotary, linear, or string style sensor where you want to set limits i.e. start, end, middle.

filth

Hmm strange thing: i only get plausible readings when i enter the sensor curve with its ohm - bar values and then set the input to mv instead of ohm. Im confused - i would expect it to work properly when i set the input type to ohm?

Matt Romanowski

I would have to play with it some. Your dash only reads voltage, so the ohm setup is to help you figure the pull up resistor and voltages.

filth

Ok i understand, that it can only measure voltage. But how come that there is an effect on the reading wheather i choose ohm or mV as the input type in the sensor creation screen?