PDA

View Full Version : Capacitive Tank Senders



danbenua
03-19-2018, 10:46 PM
I'm installing a new 5600 and have Princeton converters for my capacitive senders. My tanks
were half full when I started, and AD values of about 1870. When I drained them to prepare
for calibration I noticed that the AD values had only dropped about 100 units to around 1770.
Is it normal to have such a small range between half full and empty? If not, I would like to
know before I start filling them.
Thx,
-Dan

Shawn McGinnis
03-20-2018, 12:37 PM
Which Princeton adapters are you using? Vans / 1SP / 2SP / 5SP? If you cycle power to the senders do you see the AD_VAL go high for one second then low for one second during self test?

danbenua
03-20-2018, 03:25 PM
My converters have no external identification, but they were purchased from Van's in 2007. With the converters powered off, the AD values are about 2500. When
power is applied, the AD values increase to about 3700 before decreasing back the the "empty" values of around 1760. The damping is too great to allow
the values to stabilize during a 1 second self test. These AD values are very different from what I saw on my old 4500 which had empty at 0 and full at 700
with these same converters.

Shawn McGinnis
03-20-2018, 03:37 PM
Your EFIS may not be setup for capacitive readers. If you disconnect the 37 pin harness from the back of the EFIS does the AD_VAL drop to 0? Or by chance are you using an SV-EMS-220?

danbenua
03-20-2018, 06:24 PM
I am using the SV-EMS-220 and I specified capacitive senders when I ordered.

Shawn McGinnis
03-21-2018, 10:18 AM
Have you set your Sensor Type to Capacitive? Which of the SV-EMS-220's Enhanced General Purpose Inputs are you using (pins 8, 22, 23 or 31)?.

danbenua
03-23-2018, 02:29 PM
The sensor type is set to capacitive, but they are connected to pins 20 and 21 as shown in the installation manual.
These were not changed when I upgraded from the 4500.

Shawn McGinnis
03-23-2018, 04:37 PM
If you are a two tank user moving them to 22, 23 would be the best choice.

danbenua
03-23-2018, 05:39 PM
So are you saying that the installation instructions are wrong for capacitive senders?

I think there are resistors in the lines to the converters. Would removing them
help. Currently pin 22 is already in use for a flap position sensor, but pin 23 is free.

Shawn McGinnis
03-23-2018, 06:38 PM
The AF-5000 manual does not specify anything for an SV-EMS and Capacitive senders.

The inline resistor is not needed with the SV-EMS but will have little effect on the system.

You can move the Princeton to pin 8, 22, 23 or 31. Which ever works for you.

danbenua
03-24-2018, 08:26 PM
Capacitive senders are mentioned is on page 164 of the manual where users are advised
to connect them to pins 20, 21 of the EMS. My opinion is that omitting the information
that capacitive senders must use other pins on the SV-EMS-220 makes the documentation
wrong. I hope for the sake of future customers that you will correct it.

BTW, shifting my senders to pins 22 an 23 worked. Is there any chance that AD values
calibrated on the 4500 will also work with the SV-EMS-220?

Shawn McGinnis
03-27-2018, 12:13 PM
I'll make a request that the manual gets updated. I would doubt that the numbers are perfectly accurate between the two technologies recalibration is the only good way to ensure the gauges read correctly.

Rob Hickman
03-28-2018, 11:03 AM
Page 135 of the install manual shows the correct pins for the capacitance tanks.

rwtalbot
05-14-2023, 06:45 PM
Just to let you know I just did an upgrade from 4500s and had the exact same problem. Luckily, I found this thread, but could I suggest a few changes in the manual would really help?

- Appendix M - "Upgrading from internal AFS internal Engine monitor board to Dynon SV-EMS-220" is blank, should refer to Page 128, "converting from AFS-EM to SV-EMS-220"
- "Converting from AFS-EM to SV-EMS-220" on page 128, table could refer to the need to change pins 20 and 21 to 22 and 23 and make the changes in the calibration pages if you have capacitive probes.
- The comment here about the probes doing a self-test on startup was really helpful. Even though I have had them for 14 years I had forgotten.
- I had issues because the sensors I have are not the current ones. It would help if you referred to the need to check the sensors are all correct in the calibration pages.
- The Dynon manual for the EMS 220 shows the function and color code for each pin. It would be useful to have that in the AFS manual.

Cheers
Richard