Have 3 busses - Bat, Essntl & Main, but Main inop

[cleesgt]

I'm getting 12v readings on a D1000 for Bat & Essential busses (EMS C37 pins 1 & 2), but Main bus (pin 23) reads 4.9 volts. I've spent a couple days trying to figure out why. Facts:
- I took the Volt sensor definition file and added pin 23 to accept a voltage readout: C37_P1 C37_P2 C37_P23
- checked DB 37 connector pin 23 where it connects to EMS and it reads ~12v.
- checked Sensor Debug Data - Value column reads 4.99xx, Raw column reads 4093 (constant).
- checked Sensor Input Mapping wizard and copied Bat settings to Main (identical, but one reads accurately, the other doesn't).
Floundering and need some advice. Thanks

 

[dynonsupport]

You can't use pin 23. If you could, we would have put it in the sensor config file originally.

Pins 1 and 2 are special inputs that can measure up to 33V. All other inputs are only 5V. Thus, you are putting 12+V on a max 5V input so it will just read 5V all the time. This doesn't damage it, but it just rails out.

If you really need to read 3 voltages, then you need to use a voltage divider (two resistors) to reduce the voltage to a range that tops out below 5V, and then you need to enter that as a special voltmeter with a transfer function to back out the resistor divider so the gauge shows the right voltage.

If you don't use one of the enhanced general purpose inputs and set the pull-up to none, then you'll also need to do some complex math to deal with the internal pull up which will give you a non-linear curve.

Some info about making your own sensor files:

http://wiki.dynonavionics.com/Making_your_own_sensor_definitions

 

[cleesgt]

Using the Dynon support advice above, I made a voltage divider that looks like this:

--- +12v (Main bus) ---1000 ohm res---Dynon EMS pin 23
|
330 ohm res
|
GND
- The 12v becomes 3v at pin 23, and shows up on the display as 3v (good so far).
- I copied the 'voltmeter' sensor definition for pins 1 and 2, and pasted it back in (added a new definition) for pin 23 (removed C37_P1 and C37_P2, and added C37_p23).
- changed the equation in the new sensor definition file to Y=4X+0 (was Y=1X+0 for pins 1 & 2), essentially increasing the slope by a factor of 4 (3v x 4 should = 12v readout)
- the sensor debug data 'value' column shows ~3v reading, which is what you would expect with the voltage divider.
- Not sure why the equation doesn't apply the multiplication factor to increase the display value to 12v?

 

[dynonsupport]

Pretty sure you can't have two sensors in the sensor file with the same ID, even if they have different pins they relate to. That wasn't something we planned on. Try changing the ID to something like VOLTAGE2 and let us know.

 

[cleesgt]

Renamed the new sensor definition to VOLTAGE2 as recommended above. The definition was not recognized by the program - in Sensor Mapping the first column remainded Volt, the second column was highlighted in red VOLTAGE MEASURE, and the last column was blank. when trying to reassign the Volt column, voltage was not an option, leading me to believe the program does not recognize VOLTAGE2 (believe only accepts VOLTAGE MEASURE matched with the Volt function). When trying to access the red-highlighted VOLTAGE MEASURE there was no response when the Select button was pushed. I would appreciate a work-around, if possible, and not letting this feature rest as undoable. Thanks.

 

[dynonsupport]

Did you change the Function or the ID in the sensor file?

You need to change the ID, not the function. The function must be VOLTS, but I think you need an ID of "Voltage Measure" and "Voltage Measure Divided" or any unique term for the second one.

 

[cleesgt]

It worked! Thanks. below is the process to add a third voltage readout (that can exceed 5 volts):
-Install voltage divider in your wiring harness as described in message above.
-copy VOLTAGE MEASURE sensor definition for pins 1 & 2, and make the following edits:
-change id name to your liking, but do not change function name (will disable definition).
-assign to a voltage pin (check install guide, I used C37_P23).
-name it (I used "MAIN").
-paste it back in to sensor definition file.
-in Sensor Mapping, reassign pin to new definition.
-in Sensor display layout, (in each of 100%, 50%, 20%) click on the Sensor button, find the new sensor, and place it on each screen (& assign type, size, etc.).
-copy the display voltage reading with C_x1 set to 1 (line 16 below). Then find the actual voltage from the 37 pin connector entering the EMS (mine was pin 23). Divide the actual voltage by the display voltage. Change "C_x1=1" to read "C_x1=(insert your new ratio)". It should be close to 4 if you use the resistors used above). Mine was 4.05.
[I may have missed a step, or a label above...]

Sensor definition:

sensor={
id=VOLTAGEMEASURE2
;Verified
function=VOLTS
pins=C37_P23
name=MAIN
min_val=0.0
max_val=30.0
resolution=1
round=.1
is_piecewise=0
low_coeff={
c_x4=0
c_x3=0
c_x2=0
c_x1=4.050
c_x0=0
}
low_resistance=NONE
low2high_cross=0
high_coeff={
c_x4=0
c_x3=0
c_x2=0
c_x1=0
c_x0=0
}
high_resistance=NONE
high2low_cross=0
window=.2
shift=3
age=16
}

 

[Bruno]

Geez..you Guys amaze me..

It's like I was reading chinese...

Man I would love to be able to do that.... :-[


Bruno

 

[swatson999]

I'm not really concerned about the voltage on my various busses (jI'm set up to measure the main buss, which is enough for me), but since the backup battery state of charge can only be seen by diving down into system setup menus and such, might it be possible to split off the positive lead on the Skyview backup battery and send it to Pin 2 and display it?

Just thinking out loud....

 

[mmarien]

Better solution coming:

http://dynonavionics.com/cgi-bin/yabb2/YaBB.pl?num=1332478394/7#8