I have a Matek H743 FC slim along with a JHEMCU BS 40A BLHeli_S 2-6S ESC. The wiring I have seen shows the TX on the FC connected to the ESC. What is this wire for? I know that this ESC supports Dshor along wiht PWM and also supplies telemetry. So I would expect two wires, one from the FC to the ESC, and another from the ESC to the FC. However there is no signal to the FC since the wiring diagram shows the FC Rx pad empty. Coujld someone explain what is going on here. What wires do what and is the wiring diageam I have shown correct?
That 4in1 ESC does NOT have the telemetry (data) connection. So you could use DSHOT but you’ll miss out on a lot of the good data.
I would get a BLHELI32 ESC given the choice.
DSHOT uses the motor wires to send serial data instead of just plain old PWM, but it can be two-way as well if you are able to use bi-directional DSHOT. Then at least you get RPM data back (over those same wires).
The “telemetry” wire gives you voltage, temperature, RPM and maybe current too on some ESCs.
the TX wire is the “Telemetry” wire in BLHELI terms
No. There only needs to be one telemetry wire, it’s one-way from the ESC to the FC. The DSHOT/motor wires are two way between the FC and ESC, for error reporting and all sorts of things. BDSHOT also offers RPM data over the motor wires.
Yes, there are plenty of BLHELI32 4in1 ESCs.
BLHELI_S is a compromise to use smaller/cheaper processor chips, so there are limited capabilities.
Thanks for staying with me. Being a newbi I often don’t ask questions very clearly.
I understand that each of the PWM wires from the FC to the ESC, 4 of them, are bidirectional and cn be used as PWM or dshot in which case data is sent both ways from the ESC to the FC.
If the other single wire is for telemetry, I would expect it to connect to a Rx8 pad on the FC rather than the Tx8 pad . If the single wire is supposed to be connected to the Tx8 pad, then is data sent from the FC to the ESC on this wire?
This type of data is hard to find, at least for me.
You have one good choice with that limited ESC. Flash Bluejay firmware and use the Bidirectional Dhot firmware for the Flight Controller. No telemetry per se but Dshot protocol and ESC RPM for the notch filter. It’s the only good option for blheli_s ESC’s.
Can you suggest a 4 in 1 ESC that has all of the bell and whistles you mention? I think the ESC I have does do Dshot but probably not BDshot. Since I am making my first drone, I would like to equipt it with hardware that has all capabilities.
Dave, when you say “wiki” do you mean the Ardupilot documentation for this item?
I googled “arducopter esc telemetry” and got a number of hits to suppliers but none have any documentation for the ESC.
I am still trying to get an answer about the single wire. NORMALLY, the Tx pad of a FC means the transmit signal. The TX normally connects to a Rx on the receiving end. So in the case I have here, refer to the wiring diagrams, There is a wire between the Tx8 and the ESC. Does this mean the FC is transmitting something to the ESC? If so what? Normally, as far as I know, serial connections using usarts have one wire sending data in one diorection and the other wir receiving the data. In my case, I am wondering if the single wire is connected to the wrong pin?
I wish you get a clear answer about that ESC wire. If somebody tells you to connect to that point on your FC that would answer your question. The theory about Dschot is understood! I still use PMW on all aircraft I use, I don’t know the answer.
The telemetry data is sent from the ESC to the Flight Controller. Whether it uses the Rx or Tx pin on the Flight Controller depends on the Flight Controller. There are parameters that determine this. Some Flight Controllers can swap these, some can’t. Some only have a Tx or Rx available.
Let’s try another Google search (getting the idea?) “arducopter blheli_32”
I have done the google thing. I did not know that the FC can switch the Tx and Rx lines. If this is the case, then I guess connecting the ESC to the Tx8 pad will be ok. In any event, normally if the Tx and Rx lines are wrong nothing smokes there is usually just no communication.
I think the ESC I have will send telemetry but the Dshot is one-way. i.e. it is not a BDSshot.
When I connect these wires I will be ready for a smoke test.
Well, I keep asking what the extra wire is for. It connects between the FC Tx8 pad and the ESC. Is this the programming wire, just in case I want to do the BlueJay programming.
YHou just told me it could be either a transmit or receive depending on the configuration.
"The telemetry data is sent from the ESC to the Flight Controller. Whether it uses the Rx or Tx pin on the Flight Controller depends on the Flight Controller.
This is what I have been asking about all of this time.
