[vhbill]

Can anyone tell me what module I need to interface the Van's flat capacitance fuel sensor plates to a 0-5V input fuel level gauge such as the Dynon D-180?

Bill
RV-6A

 

[JordanGrant]

I don't know who makes it or what its called, but the Advanced Flight Systems guys (the engine monitor makers) have a module that works great in their system.

 

[moodyjr]

Vans Capacitance Plates Interface

I have the Vans plates in my RV-8A & purchased the Princeton Electronics senders to interface with GRT EIS 4000 I am using in the panel ($95 each last year). The EIS inputs use a 0-5V signal.

In any event, I ended up using the EIS inputs for other parameters and have subsequently purchased 2 no. 1-1/4 in dia UMA (capacitance) fuel level indicators which use a 0-5V signal.
I have bench tested this combination & it works OK so these senders would probably be OK with any other indicator which used a 0-5V signal.

To be on the the safe side, first check with Todd Stehouwer at GRT/ Princeton
616 243-8800 PH
616 245-7707 FAX
[email protected]

I am having some problems with the interface between the senders & my tanks. The senders are set up for capacitance of 200-500 pF. For some reason my tanks measure about 100 pF. Still sorting this one out with Todd.

cheers
John Moody
RV-8A

 

[N941WR]

Bill,

Post this on Dynon's forum, better yet, search their forum. I'm sure it has come up before.

When you are done, please post the answer back here as others of us will need that info as well.

Thanks.

 

[chaskuss]

Here is a DIY Solution

Can anyone tell me what module I need to interface the Van's flat capacitance fuel sensor plates to a 0-5V input fuel level gauge such as the Dynon D-180?

Bill
RV-6A

Bill,
20 years ago (September 1989), Jim Weir wrote an article in KITPLANES on how to make these modules yourself. I have a copy of the article, which I can email to anyone interested. I don't want to post it here, as I have not asked permission to do so from the author. Simply contact me off list.
Charlie Kuss

 

[ArVeeNiner]

Dynon sells them

Dynon sells those modules.

 

[chaskuss]

A Question?

Can anyone tell me what module I need to interface the Van's flat capacitance fuel sensor plates to a 0-5V input fuel level gauge such as the Dynon D-180?

Bill
RV-6A

Has anyone tried to use the Electronics International Capacitance to Voltage Converter Module sold by Vans for the above purpose? I'm referring to:

IE P-300C on page 31 of Vans new Accessory Catalog. These are only $45 each. I spoke to Dale at Vans. He said that they were designed for the EI gauges (BIG $$$).

I'd like to find something that will work with the common resistive type fuel gauges (Vans, Stewart Warner or Mitchell)

Charlie Kuss

 

[N941WR]

Charlie,

Dynon sells the converters for $50. If you are running a Dynon, why not use their units?

These should also work with other fuel gauges.

I've been using mine for two years now with no problems.

 

[chaskuss]

Found it

Dynon sells those modules.

Thanks Kelly,
Adding Dynon to my Google search terms results in

Capacitance to Voltage Converter for Vans Capacitance Plates #100654-000 @
$50 each. Does the Dynon EIS use a 0 to 5 volt reference?
Charlie Kuss

 

[chaskuss]

Will they work with Resistive Analog Gauges?

Listers,
Does anyone know if the Dynon, Electronics International or Princeton converter modules will work with the more basic analog fuel gauges sold by Vans, Stewart Warner or Mitchell? Do any of these converter modules contain a "trimming" potentiometer to calibrate the Vans Capacitance Senders to these gauges? Usually a "trimming" potentiometer will have an external adjustment point (usually an adjustable screw).
Charlie Kuss

 

[az_gila]

But Jim Weir did...

Bill,
20 years ago (September 1989), Jim Weir wrote an article in KITPLANES on how to make these modules yourself. I have a copy of the article, which I can email to anyone interested. I don't want to post it here, as I have not asked permission to do so from the author. Simply contact me off list.
Charlie Kuss

...put them on his web site for all to read - 1989 Kitplanes article...

http://www.rst-engr.com/rst/articles/KP89SEP.pdf

..and 3 DIY pages here - later from 2000...

http://www.rst-engr.com/kitplanes/KP0006/KP0006.htm
http://www.rst-engr.com/kitplanes/KP0007/KP0007.htm
http://www.rst-engr.com/kitplanes/KP0008/KP0008.htm

No copyright violations were conducted in the making of this post....

 

[rzbill]

Bill,
20 years ago (September 1989), Jim Weir wrote an article in KITPLANES on how to make these modules yourself. I have a copy of the article, which I can email to anyone interested. I don't want to post it here, as I have not asked permission to do so from the author. Simply contact me off list.
Charlie Kuss

I have this breadboarded on the bench right now. Looks like it works OK, However, due to the low cost of the Dynon convertor and the unit noted through Vans, I will probably look there rather than finishing the Jim Weir units. Burning boards and making a chasis takes me longer than doing the initial circuit build. FYI for others, Jim assumed 360 picofarad tank capacitance. I measured my empty tanks at 180 pf.

 

[chaskuss]

Dynon unit won't work

I have this bread boarded on the bench right now. Looks like it works OK, However, due to the low cost of the Dynon converter and the unit noted through Vans, I will probably look there rather than finishing the Jim Weir units. Burning boards and making a chassis takes me longer than doing the initial circuit build. FYI for others, Jim assumed 360 picofarad tank capacitance. I measured my empty tanks at 180 pf.

Bill,
I just received an off list reply from Kelly (post 6). The Dynon units have the calibration adjustment in the main instrument, not in the converter module. Due to this, they would not work using standard resistive gauges. That is what I asked about in post #10.
Looks like I'll go with the Jim Weir DIY modules. Are you building your converter modules from Jim's 1989 article or the newer 2000 article that Gil provided the links to?
Charlie Kuss

 

[rzbill]

Rats - I was looking for an easy way out.

OK, if you are correct, the Dynon won't work for me and neither will the EI unit through Van. I have not personally investigated the Dynon unit but I will take your word for it. The EI unit appears to be specifically designed to work with their gage used with capacitance sensors. According to the EI web site, the convertor outputs a 5v square wave. I need a 0-5v DC that I can use with a GRT EIS 4000 (per the obsolete Rev G manual I have).

I am using the 2000 downloads from RST that Gil posted.

Don't expect to get some of the resistor and cap values by walking into Radio Shaft. Their selections are nearly nil nowadays. That has slowed me down a bit since I hate ordering something that is cheaper than the shipping.

I have the oscillators working. I will probably breadboard the comparator section this week. I have already designed a board, but have not had time to burn it. One of my engineers with avionics design experience suggested some changes to the traces after he saw it. (reduce RF sensitivity)

 

[rzbill]

I am having some problems with the interface between the senders & my tanks. The senders are set up for capacitance of 200-500 pF. For some reason my tanks measure about 100 pF. Still sorting this one out with Todd.

cheers
John Moody
RV-8A

John,
Maybe the plate jumper is broken and you are only getting the capacitance of the one plate that is closest to the BNC connector. If mine measure 180 pf and you are around 100 (90?), this might be it. It would certainly be unusual for that to be the case in both tanks though.

 

[chaskuss]

PCB group buy?

snipped
I am using the downloads from RST that Gil posted.
snipped
I have the oscillators working. I will probably breadboard the comparator section this week. I have already designed a board, but have not had time to burn it. One of my engineers with avionics design experience suggested some changes to the traces after he saw it. (reduce RF sensitivity)

Bill,
I seem to remember someone mentioning that there is a company which will design and manufacture printed circuit boards in small quantities. Anyone know who the company is or what something like that would cost? Perhaps if 5 or 10 builders were interested, we could do a "group" buy of PCBs for this project??? (assuming the price was reasonable)
Charlie

 

[az_gila]

PCB Express is one...

Bill,
I seem to remember someone mentioning that there is a company which will design and manufacture printed circuit boards in small quantities. Anyone know who the company is or what something like that would cost? Perhaps if 5 or 10 builders were interested, we could do a "group" buy of PCBs for this project??? (assuming the price was reasonable)
Charlie

...or maybe two companies...

http://www.pcbontime.com/price_list.html#proto

http://www.pcbexpress.com/products/prices.php

You can also double up or triple up a design on a bigger board and seperate them your self to get a lower price if your final boards are small, if you can keep the actual fabricated board under a size price break dimension.

 

[rzbill]

I'll consider it, but its not ready to order

Charlie,
Buyers need to understand that I am an amateur (with some previous success) at electronics and the actual board trace design is untested as of today. I have not selected the chassis or IO cable connections so the board is really not ready to print yet. I will consider your proposal. PM me in a few weeks to see if I have gotten any further (9-5 job gets in the way).

 

[rzbill]

Probably won't continue with RST plan

Gentlemen,
I have reviewed the Dynon Capacitance to Voltage convertors and plan to use them unless further information indicates otherwise. I understand the Dynon units mentioned above do not have internal signal adjustment so the instrument or indicator must take on that duty. I believe the GRT EIS 4000, which I plan to use, has this ability.

I can report that the RST schematic does work on the bench per oscilloscope testing. I did have to increase the gain on the output OP-AMP (to get 1v to 6v output swing) probably because of the lower capacitance of the RV tank plates vs his example plates, but otherwise it was unchanged from Mr Wiers design.

To finish, the work ahead of me is worth a lot more than the cost of the Dynons to burn boards, design a chassis that is WAY bigger than the Dynon and figure out where to mount my rats nest. I would much rather do it with the Dynon units and then publicly hand over the numerical settings needed in the EIS.

Sorry for bailing.

 

[Noah]

Capacitive Senders for use with AFS

Reopening this old thread. There seem to be several options for capacitive converters, notwithstanding the homebuilt versions discussed above. Not sure which are compatible with Advanced Flight Systems as there is not much info available for what is needed. Options seem to be:

Option 1: Buy from Vans, P/N IE ACS CAPAC. CNVTR., $208
Option 2: Buy from Dynon, P/N 100654-000, $50
Option 3: Buy from AFS, P/N not listed on website, price unknown.
Option 4: Buy direct from Princeton, can't locate a website for Princeton (?)
Option 5: Buy Dynon part from Aircraft Spruce, P/N 10-02159, $49.95

Obviously a big price difference in the Vans and the Dynon converters. How many of each are needed - assume 1 for each wing or are these dual channel to handle both tanks? Is Princeton no longer making these units, or are they no longer selling them?

Thanks in advance for any help on this.

 

[Brantel]

If you go Dynon, you need two. They clip right on the wing root to the BNC connector installed in the tank.

 

[dhall_polo]

dynon and afs ok

I have (2) dynon capacitive senders talking to my AF3500.

Works great.

Don

 

[Noah]

I just spoke to Todd at Princeton regarding the output range for his converters. He makes and sells 3 different models. The model ending in 1S has one setpoint, you press a button on his unit when powered up, tanks empty and this defines 0 volts. The range on this unit in a Vans installation is about 0-3V. The upper range is not settable.

The 2S has two setpoints. When the unit is powered and with tanks empty, you press a button on the converter and this defines 0V, empty. Then you fill the tanks and hit a button which defines full and this sets the output at 5V. Hence with this unit you are getting the full 0-5V output. Both the 1S and the 2S are $95 purchased direct.

The 5S has five setpoints, so you start at zero, hit the button to define 0V = empty. Add 25% tank capacity and hit the button - repeat 3 times to give you a fairly linear 0-5V output signal with tank level. The 5S unit is a little more $.

With all these units you THEN have to do a separate software calibration in your EFIS/EIS where you fill the tank in small increments of 2 or 3 gallons (follow the manual) and define setpoints in the EFIS/EIS to indicate the tank level corresponding with the voltage being sent by the converter. Bottom line, any of these will work but if you want the highest resolution (use of the full 0-5V EIS input signal), you don't want the Dynon converter or the Princeton -1S model - buy the -2S or -5S.

Todd (of Princeton) is housed in the same building as GRT, 612-245-7700.

 

[Brantel]

Good info Noah...Bet if Princeton would advertise some of this, they would sell many more units!!! They need a website! (or make it easier to find)...

 

[N282S]

EIS4000 auxsf auxoff values

Gentlemen,
I have reviewed the Dynon Capacitance to Voltage convertors and plan to use them unless further information indicates otherwise. I understand the Dynon units mentioned above do not have internal signal adjustment so the instrument or indicator must take on that duty. I believe the GRT EIS 4000, which I plan to use, has this ability.

If you do plan to use the Dynon sensors with the vans capacitive plates and the eis4000, which looking at your log pages I believe you are, then you will need to come up with the auxsf and auxoff values.
After much trial and error, I found these values to work:
auxsf = 1367
auxoff = 865

But, if your not using the dynon sensors with the grt eis4000, well then, never mind.

 

[rzbill]

Maffs and Gazintas may just work after all

I want to give a hand to Steve and Brian for the info below that helped me get in the ballpark when using the Dynon convertors and the GRT EIS.

When I started messing with it, I was getting zilch and wondering if something was broken. (especially my wiring)

After much trial and error, I found these values to work:
auxsf = 1367
auxoff = 865

I

I did some curve fitting by using the voltage levels posted by Brian (different thread) since they applied to the Dynon convertors in an RV7 tank shape. I decided to determine the y=mx+b values that would fit the lower part of the curves up to the inflection points around 14 gallons. While the EIS 4000 does not have the ability to deal with the nonlinear curve, the graphical display on the Horizon 1 will do OK through the use of a map of paired values. I'll deal with the 14 gal to full part of the curve using the map.

Anyway, after doing the math, I came up with an auxsf value of 135 (m of mx+b fame). Hmmm. Why is it 10 times different than Steves? AHA! there is an EIS setting that moves the decimal point on the display. Once I took that into account, my auxsf was 1350. In EIS language, that is really close to Steves 1367.

Next, the AuxOff value (b). Math said the value needed to be around -500. Fine. To enter a negative in the EIS, you double it and add a 1 (so 1001). My actual "negative value" entry is running slightly larger at around 1051 in order to get zero when the tanks are empty (and a proper read on 5 gal) but again, in EIS language, that is not very far from Steve. (865 = neg 432)

I'm not done doing the gage calibration, but the early results were encouraging to me.

Thanks Gents.