Pressure sensor

MoTeC supplied sensors, valves or wiring discussion

Pressure sensor

Postby JohnTSI on Wed Feb 04, 2015 9:42 am

I would have thought I could find this somewhere or in the SDL tables but I have two 150psi Motec pressure sensors MEPT 150Gs. I cannot seem to find any 150psi sensors in the SDL config tables, strange considering its the Motec sensors. Does anyone have the config file for these? I know they should be linear. I tried to used the setup for a Honeywell 100PSI sensor and changed the 100psi voltage (4.509) to 150PSI and deleted all points between there and 0 (.5V) only having 0 volts and the voltage they used for 100 psi and it doesn't seem to be correct with the reading I am getting.

Thanks
JohnTSI
 
Posts: 9
Joined: Mon Jan 26, 2015 9:45 am

Re: Pressure sensor

Postby Scott@FP on Wed Feb 04, 2015 11:02 am

Be sure the calibration is in volts or millivolts for that device, some devices use a millivolts table unlike an ECU which uses volts plus 3 decimal places. Usually the data entry field for the calibration will indicate whether it needs mV or V plus 3 decimal places. Its easy to miss, we've all been there. Also they are usually a straight linear cal, if you test it and it needs an .009 volt offset at your calibration point to match, both ends of the cal need that same offset.

In other words if its supposed to be 1.300v at 100 KpaA but it is 1.309v, you'd use a two point cal of .509v for 0 KpaA and 4.509 for 500 KpaA for a 4v span unit with a .5v offset. 4v (span) / range abs in kpa = voltage change per kpa, add offset (.5v) = 1.300v @ 100 Kpa.
Scott@FP
 
Posts: 420
Joined: Thu Jul 10, 2008 6:57 pm

Re: Pressure sensor

Postby JohnTSI on Wed Feb 04, 2015 10:49 pm

It seems I must not have either resent the config file after I rescaled the sensor the first time or did something else incorrectly because it was still set to 100psi instead of the 150.

Here is another stupid question I have a couple other motec pressure sensors here the labels have seemed to come off of. Is there another way to tell what sensors they are without the label?
JohnTSI
 
Posts: 9
Joined: Mon Jan 26, 2015 9:45 am

Re: Pressure sensor

Postby Scott@FP on Thu Feb 05, 2015 3:54 am

Sort of. Majority of screw-in round body transducers have a 0.5v-4.5v ratiometric output. So if you plug one in exposed to atmo and it reads very close to 0.5v its probably a gauge or sealed gauge sensor, crank it up with a pressure regulator and see where it is at 4.5v. If it reads between 0.6v-2.5v its probably an absolute multi bar range sensor, divide the atmo reading into the span (4v) and you get the approx. range, 4v / 0.8v = 5 bar. If it reads just under 4.5v its probably a 1 bar. 10+ bar abs sensor might fool you.
Scott@FP
 
Posts: 420
Joined: Thu Jul 10, 2008 6:57 pm

Re: Pressure sensor

Postby JohnTSI on Fri Feb 06, 2015 12:09 am

Thanks Scott, got it all sorted now apparently the second sensor I thought was a 150 was actually a 75. Swapped in a 100psi sensor on the fuel side and rescaled the 150 for oil and everything is working properly. Now just have to install the backpressure sensor and we should be about ready to redyno.
JohnTSI
 
Posts: 9
Joined: Mon Jan 26, 2015 9:45 am


Return to Sensors, Valves and Wiring

Who is online

Users browsing this forum: No registered users and 1 guest