Resistance to voltage conversion

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Steve
Posts: 43
Joined: Sun May 19, 2013 7:38 pm

Resistance to voltage conversion

Post by Steve »

I have now fitted a new air temp sensor and a new oil temp sensor. They come with the temperature vs resistance table but I need to convert this into voltage to setup the linearisations in the sensor settings.

How can this be done?

Cheers
Steve
Toyota Supra BoostLab S366HF - 821 rhhp / 644 ftlbs - Mapped by Ryan
Syvecs S6 with aftermarket DBW setup on Greddy Style Intake manifold.
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secure
Posts: 254
Joined: Tue Apr 21, 2009 7:38 am

Re: Resistance to voltage conversion

Post by secure »

I have made a worksheet in last years. It calculates the voltage multiplier with the entered pull-up resistor value. Syvecs is 3000 ohm.

so here it is..(revised)
http://www.syvecs.co.uk/forum/download/ ... 8af3d9452e

If you need more voltage resolution take a look at interpolation page on the same sheet.

Cuneyt
Last edited by secure on Mon Jul 29, 2013 1:59 am, edited 2 times in total.
Steve
Posts: 43
Joined: Sun May 19, 2013 7:38 pm

Re: Resistance to voltage conversion

Post by Steve »

Excellent, thanks for that :)

Is it possible to change the sensor breakpoints or is it a case of matching it up as best as possible to the nearest voltage point?
Toyota Supra BoostLab S366HF - 821 rhhp / 644 ftlbs - Mapped by Ryan
Syvecs S6 with aftermarket DBW setup on Greddy Style Intake manifold.
- SOLD 2017
TimH
JT Innovations
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Joined: Wed Sep 01, 2010 3:51 pm

Re: Resistance to voltage conversion

Post by TimH »

If these are sensors supplied by me, then there are Syvecs linearisation database files on the website, to save you having to do this.

If not, then simple ohm's law applies, based on a 5V supply and a 3K pullup in the Syvecs.

And, yes, you can define all the points yourself.
Steve
Posts: 43
Joined: Sun May 19, 2013 7:38 pm

Re: Resistance to voltage conversion

Post by Steve »

I have set most of it now I think, I have set them as close to the current breakpoints using the excel sheet above.

With how they were set previously the ECU was seeing ACT of 60 when it should have been 30 and EOT of 160 when it should have seen 90 odd. So they were a little out. :D

The sensors were from EFI-tuning.co.uk.
Toyota Supra BoostLab S366HF - 821 rhhp / 644 ftlbs - Mapped by Ryan
Syvecs S6 with aftermarket DBW setup on Greddy Style Intake manifold.
- SOLD 2017
secure
Posts: 254
Joined: Tue Apr 21, 2009 7:38 am

Re: Resistance to voltage conversion

Post by secure »

Tim is right please check again the pull up resistor value. It should be 3000 ohm not 3300.

I revised the sheet as well.
Attachments
SensorCAL.xlsx
NTC Resistance vs. Voltage Calc.
(28.97 KiB) Downloaded 1124 times
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