What values to set for telemetry?

[1SQ]

I've been using my 9X radio with the open9x firmware plus FRsky DHT DIY Tx with the D8R-xp module, but dont know how to set the telemetry.

I have the A1 and X pins on the RX connected with a jumper to enable the internal voltage monitoring of the flight pack. D8r manual says "A1 (INTERNAL): MAX VOLTAGE 3.3V, DIVISION RATIO 4:1". What is that mean to me if i'm using 4s lipo? How do i set the values on my 9X so i can monitor and assign alarms to flight pack voltage?

What do i put on the following?

A1 CHANNEL 0.00 VOLTS? TO WHAT VOLTS?
RANGE? TO WHAT VALUE?
OFFSET? TO WHAT VALUE?
ALARM? TO WHAT VALUE?

pLS HELP.

[gohsthb]

First, I must be misunderstanding this. Are you powering your receiver directly from a 4s lipo? Fully charged that is 16.8 volts, the receiver is only rated for 10 volts!
So what I am going to assume you are doing is powering the Rx through a BEC. So you can only put 3.3V into either the A1 or A2 port. Any higher than that and you will need a voltage divider. That is what the "battery voltage sensor" from Frsky is, just a set of voltage dividers. What you can do is set A1 to 13.2. This comes from 3.3 * 4:1 = 13.2. So with a 4:1 divider you can read a voltage that is 4 times higher than the maximum input voltage (3.3).
Range = 13.2
offset = 0
Alarm = (set to whatever you want it to alarm at)

besides that there is always the manual.

-Gohst

[1SQ]

The receiver is powered thru the FC (KK2), according the the FRsky if A1 and X pins are jumped together it becomes a internal voltage monitoring vice external without the jumper. In my understanding of what was stated in the FRsky manual i dont need any other sensor hub to monitor RX/flight battery voltage. I will try the formula your posted.

[Kilrah]

The "internal" voltage monitor can only measure the receiver's internal voltage, i.e. what it's being supplied with, which is a constant, regulated 5V from the ESC's BEC in your case
So yes you CAN measure that, but it's useless.
If you want to measure the battery's voltage you need to connect the battery "externally", i.e use an FBVS-01, with a divider ratio of 6 (so that your 4s' battery's maximum voltage of 16.8V doesn't exceed the 3.3V measurement capability of the receiver).
Voltage range thus needs to be set to 6 * 3.3 = 19.8V.

[1SQ]

Ahhh ok, this makes it clear. I hate it buying things from China with minimal information. they should sub-contract documentation/publications to the US on all the products that comes out of that country.

[Dthomson39]

I have been playing with the simpler voltage sensor with my Taranis connected to the balance plug n a 3 cell lipo and while it works fine there seems to be a difference between the voltage measured using a multimeter and that shown on the display. Is there a way of adjusting the displayed voltage to better match the actual measured one? Also the voltage was initially lower than it ended up reading - does it take some time to calibrate itself before reading the final level?

[Kilrah]

Is there a way of adjusting the displayed voltage to better match the actual measured one?

Yes, the Range setting for the A1 or A2 port your sensor is connected to.

Also the voltage was initially lower than it ended up reading - does it take some time to calibrate itself before reading the final level?

No. Check your wiring, you might have a floating connection. Would explain the error too.

[MikeB]

Is this the small sensor that just gives you a voltage as A2?

Mike.