First experiences with Xact servos: Success, then not so much

[Landru]

My first experiences with Xact servos are a mixed bag.

Discovering the telemetry sensors for a HV5611 was straightforward with a GR8 bound to my QX7 ACCESS. Executing the programming Lua script went without a hitch.

However, after setting the servo's Physical ID, Servo ID, and S.port channel ID all to 6, the servo does not respond to the channel 6 S.bus output. More worrying, it is no longer discoverable by the programming script. However, it does respond to a PWM signal, and the telemetry data seems to be active.

Have I now got myself a PWM-only servo?

Flashing new firmware to the servo did not fix the problem. I have a bunch more Xact servos but am hesitant to risk another one until I get a handle on the issue.

Any suggestions? Am I overlooking something? My sole reason for buying a bunch of Xact servos was for their S.bus capability. It's a disappointing start.

 

[Landru]

A knowledgeable user on RCGroups pointed me in the right direction: After programming a servo, it may be necessary to delete and rediscover all its telemetry sensors. It's a pain if you have a bunch of sensors referenced in logical switches. Anyhoo, that's how it works.

One other thing threw me for a loop: In the Lua script, it's necessary to 'select' the 'Yes' option for 'Save to changes to flash' in order to apply the changes. There is no other prompt or mechanism to save.

Anyone stumbling on this thread in future may find the discussion and details on RCG useful.

 

[Wayne]

Thanks for the feedback. Was wondering if you had managed to put it into f.port mode and that was causing the issue, but guess it is more FrSky weirdness.

 

[Wayne]

OK - I guess it sort of makes sense.. You changed the ID, so it needed to discover it again. FrSky could do this better..

 

[Landru]

Yup, I think there's room for improvement.

Better documentation would be a good start. There's pretty much nothing that I could find aside from the RCG thread.

On the bright side, the HV5611 I've been playing with on the bench is very nice. I love the idea of going all S.bus.

 

[Wayne]

They for sure have some good features packed in there for the money. I'd like to do some videos and things about them, but time is always ticking..

 

[Landru]

I hear you.

BTW I wasn't particularly interested in the servo telemetry until I saw it in action.

 

[Wayne]

Yeah, that mirrors my experience.

 

[Landru]

Voltage for 5701?

Hey Wayne, did your team happen to test the 5701 on 2S Lipo?

I just noticed that there are two versions of that servo according to the FrSky Website:
5701 (D5701) : 3.6–6.0V
HV5701 (H5701) : 6.0–8.4V

I suspect that I have lower voltage 'D' version. My plan was to use them on 2S but perhaps that's not a good idea.

Best,
Andrew

 

[Wayne]

We had a discussion about this with FrSky. They have confirmed it is a 2S compatible servo. Just the HV version is optimized for a little better power at 2S, but less at lower voltages. Some other servos brand have done the same thing, it is kind of annoying. The differences are so tiny I do not feel it warrants 2 different servos, it just confuses customers.

 

[Landru]

Wonderful. Thanks for the very fast response, Wayne!

I totally agree about the possibility for confusion.

FrSky even offers different firmware for the different variants. I'll do my best to avoid using the wrong version. Hopefully, it wouldn't be a fatal error.

 

[Landru]

BTW a fellow over on RCG made a suggestion that I thought was very good:

That FrSky receivers be configurable to output the F.bus signal on the servo pins.

A telemetry-enabled Xact installation would be very easy with such an option.

I know you have FrSky's ear so I thought to mention the idea here.

 

[Wayne]

Good idea.