([PID.2811]/.04)+.5
should be the formula. To increase the offset, you will adjust the .5 volts accordingly. I have been doing many things to my car and still have yet to activate my sensor and begin logging it. Hopefully soon though.
([PID.2811]/.04)+.5
should be the formula. To increase the offset, you will adjust the .5 volts accordingly. I have been doing many things to my car and still have yet to activate my sensor and begin logging it. Hopefully soon though.
Hsquared racing engines RHS 427, Procharger F2, Moran Billet Atomizer injectors, Alky Control,Mast LS7 heads, Nitrous outlet kit,Tilton quad disc clutch, DSS shaft, RKT56 ZR1 trans, RPM Quaife diff. Built and tuned by yours truly.
.5v is 0psi
4.5v is 100psi
(0/.04)+.5=.5
incorrect.
(4.5/.04)+.5=113
also incorrect.
25 is the slope & -12.5 is the intercept.
(V*S)+I
Makes sense. That way .5v=0. I didn't actually run my formula or I would have known is wasn't right.
I am wondering if the formula ([PID.2811]+-.5)/.04 would work as well.
Since I have a Corvette, the EGR is turned off. I haven't gotten the output to show up in my logs yet, but I also haven't done much troubleshooting. I did go in the General tab and set the EGR to "enable" and set some (if not all) of the EGR items in the DTC's page to report and I have yet to see an output. I get the "unsupported" comment once I start the scan. I'll keep digging.
Last edited by blownbluez06; 01-13-2010 at 10:29 AM.
Hsquared racing engines RHS 427, Procharger F2, Moran Billet Atomizer injectors, Alky Control,Mast LS7 heads, Nitrous outlet kit,Tilton quad disc clutch, DSS shaft, RKT56 ZR1 trans, RPM Quaife diff. Built and tuned by yours truly.
This is the formula: (V/.04)+(-12.5).
If you have an offset, calibrate the external inputs or compensate for it in the pid but
don't substitute the Intercept (-12.5) for another number.
You can use AA battery (1.5v) to see if you have an offset.
Is the sensor properly powered/grounded?
Here is a spreadsheet for WBO2 expressions but it will work for other devices as well.
Last edited by mr.prick; 03-03-2010 at 03:31 AM.
Sorry for not responding sooner. I have been caught up with other issues. I am a solder and heatshrink guy, so it is properly powered and grounded. Thanks for that spreadsheet. I finally got it to work with the formula provided and verified it with an analog gauge. Since I have an adjustable regulator, I was able to turn the pressure up and down while monitoring the readings and it was close enough for government work. I then got a virus (damned 2010 internet security virus) and after I cleaned it out of my laptop my config files were screwed up. I also have been doing a bunch of other work to the car. I'll have to make my config files again soon. Still have other fish to fry right now.
Just curious why I would use a AA battery to verify offset. Because it's lower than 5 volts, stable voltage output and I can put a known good meter on it for comparison?
Last edited by blownbluez06; 03-03-2010 at 04:51 AM.
Hsquared racing engines RHS 427, Procharger F2, Moran Billet Atomizer injectors, Alky Control,Mast LS7 heads, Nitrous outlet kit,Tilton quad disc clutch, DSS shaft, RKT56 ZR1 trans, RPM Quaife diff. Built and tuned by yours truly.
Final follow up on this.
For any formula on a linear pressure sensor, take the total pressure range and divide it by the volt range.
100/4=25
Since you can't multiply the sensor output (also the EIO or PCM input) signal by a factor, you divide it by it's inverse. 1/25=.04
Take your ([PID]/.04) + (- your intercept).
Since the sensor starts at .5 volts, then the intercept will be .5 * 1 volt value. .5*25 is 12.5 subracted from 0, so the intercept will be -12.5
([PID.2811]/.04)-12.5 is what I used for the EGR and I had to put EGR position voltage in your table to be able to log it. It works great!
Just an FYI, if you were to use a 150psi sensor with a .5-4.5v range it would change to ([PID.2811]/.0267)-18.75
Feel free to substitute with the pid of your choice.
Last edited by blownbluez06; 06-14-2011 at 02:22 AM.
Hsquared racing engines RHS 427, Procharger F2, Moran Billet Atomizer injectors, Alky Control,Mast LS7 heads, Nitrous outlet kit,Tilton quad disc clutch, DSS shaft, RKT56 ZR1 trans, RPM Quaife diff. Built and tuned by yours truly.