Custom Sensor Setup

[rfazio1951]

I've been reading through the posts here trying to figure out how the sensors should be setup. I hope someone can clue me in on the resistor pull up that is required for certain sensors. I just can't seem to figure out what your talking about. To me if you have a sensor that gives a certain resistance for it's range of operation, like 100 ohms to 1000 ohms say for a fuel level sensor. Wouldn't I just need to assign values to the range, like 100 ohms is a full tank of fuel and 1000 ohms is empty etc. I don't see that in the config file. I guess I'm just not understanding how the sensor file and math works.

 

[dynonsupport]

Ok, lets start at the top:

If you're connecting a Dynon-provided sensor to SkyView, or one that SkyView is compatible with, all you do is hook it up per the manual, and then select the sensor from a list when you do your pin mapping. If you use one of the pre-canned EMS starting setups for major engine types from our download page, you don't even need to do that for all or most of your sensors.

Fuel tanks are special. They have a calibration procedure, unlike other sensors, that maps the resistances to fuel quantity levels.

Now as for other sensors - that is - one that isn't supported natively by SkyView that you want to use: many sensors don't have linear outputs. That is, two points with a straight line between them aren't going to be good enough to calibrate them well along their entire range of output. SkyView uses a 4th order polynomial to describe all sensors, which means you can make some funky looking curves. A linear output is still possible, but you still need to turn it into an equation that can be plotted by its coefficients. We provide documentation for how SkyView interprets these sensor definitions, but it is a bit technical. The documentation for sensor files is here: http://wiki.dynonavionics.com/Making_your_own_sensor_definitions. The sensor file is ONE of the files that is output when you export your settings.

Also, we did something of a tutorial on this topic that you can find in this thread:

 

[dynonsupport]

Also, from a technical perspective:

SkyView can't read resistance, it can only read voltage. This is technically true of just about every circuit in the world- your multimeter reads voltage if it's in volts, ohms, or amps mode, but it uses various methods to convert ohms or amps to volts so it can read them.

To read resistance, one method is to have two resistors hooked to a voltage source, and this creates a voltage divider. With a known resistor and a known voltage, you can determine the resistance of the second unknown resistor, which is the sensor in your case.

SkyView lets you choose the right pull up resistor. Unfortunately, even this requires some work, since both the maximum and minimum resistances expected change which one you want. This is comparable to choosing the "range" on a multimeter, where you need to tell it 0-200 ohms or 0-2000 ohms before you make the measurement, since it can be more accurate with the 0-200 range than the 0-2000.

If you post the min/max resistances of your sender and what pressure or temperature those represent, we can give you the values you want to put in the config file.

 

[rfazio1951]

Ok I read through the documentation and I am starting to understand the math. If I record the voltages from the skyview ems setup screen will that allow you to give me the proper setting? Or will the sensor type I have selected for that sender effect the readings? In other words is the voltage displayed actual or after the pull up resistors are applied?

 

[dynonsupport]

The pull-up resistor is what creates the voltage, so it does depend on sensor type selection. You'll want to use a sensor type that uses the resistor you want to use, and then you can read the voltage. Note that some sensors have a piecemeal curve that uses two resistors that change over at some point on the output range, so don't use one of those.

 

[alpezfly]

I need to intall a temperature sensor on the airbox of Rotax 912.
Range temperature I need to check is from- 10 to + 50 CELSIUS°.
please give me some tips:
- Is it necessary to go to a certified Dynon centre (I live in Italy)
- Can I use EMS OAT 100433 sensor connected to GP input 22 or 23 in Flight DEK D180
- Can I display temperatures in Celsius degrees
- Can I set alarm on this sensor

 

[dynonsupport]

No, Yes, Yes, Yes are the answers to those four questions

The first question has a bit more complicated an answer. If you're a home builder or otherwise authorized to work on your aircraft, then you can perform the modification yourself. If there are laws that say that there are restrictions to who can work on your aircraft, or if you need permission from the manufacturer to modify it, then you need to follow those rules. But Dynon itself imposes no such restrictions. For example, if you have a US registered SLSA, the owner can't make changes if they're not an LSA repairman or A&P, AND, the manufacturer needs to authorize any changes to the aircraft.