Brake Pressure Sensor Problems

[disquek]

I've just got two of the RT brake pressure sensors plumbed into the car and wired into the DL1.

The Dash2 and DL1 both show 80-100psi of pressure when there is none (brake lines disconnected).

The specs on the website store show that the sensors should put out .5v at 0psi. However they are both putting out about .59v at 0psi.

Also, they are not the same. One says it sees 86 psi, the other says 98.

Are the sensors both bad? Can someone measure the output of these sensors at 0 psi?

-Kyle

[blentz2]

100psi without pushing on the brake huh - that explains sooo much!

[osborni]

Are you putting out a clean 5.0 vdc to the sensor?
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BMW 2000 MCoupe

[disquek]

It turns out that this is a known issue.

RT have released a new formula for the sensor which subtracts 72 from the base value.

But to be honest, this seems like a "work a round" rather than a fix.

I'd like to see the vendor of these sensors actually fix the sensor.

Kyle

[osborni]

Yeah, that would be nice.

The reality is that doing a calibration of sensors is sort of expected. The error you are seeing is around 1%, which isn't bad for a relatively low cost pressure sensor.
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BMW 2000 MCoupe

[Support]

The equations in the knowledge base are different to the ones used in the Analysis software. The ones in the DASH2 and Analysis software are based on the datasheets, the one on the knowledge base are based on our actual measurements of sensors. From the next build of the software they will all use the measured values and will give a more representative answer. In the mean time, feel free to set up your own equation with the following values to get the better answer.


Pressure in Bar 62.5*x-36.25

Pressure in psi 906.25*x – 525.625
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Posted by the Race Technology support team

[disquek]

Support,

Have you measured these senders accuracy at any point other than 0psi? What a was the result.

Mine are off by a different number than your shift (85 and 100).

For the price of these sensors, I'd expect a more accurate and consistent result. The typical range of brake system pressure is to 1000 psi. Being off by 10% of that is not reasonable.

Please reconsider these sensors for ones that are more accurate.

-Kyle

[disquek]

Bump.

I'd like to know if these senders have been calibrated or if the new formula is simply the result of seeing the error at zero PSI.

-Kyle

[Support]

Hi,

We paid to have 5 of the sensors calibrated some time ago (12 months+?) and the offset was the same thoughout - so the mystery remains as to why the spec sheet isn't right for these sensors, but we are confident that our calibration is accurate.

The problem is that sensor come direct from Bosch motorsport and despite us asking a number of times we've never had an answer. We found this problem several years ago and though it might be batch to batch variability, but we've sold 100's and they all appear to be the same. That is the problem is dealing with huge companies like Bosch, they are not too bothered about supporting unless your name is Ford/Toyota/GM etc.

Thanks,

Support
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Posted by the Race Technology support team