Airspeed sensor upgrade woes

[ululi1970]

My setup:
SR10 Pro, FW 2.1.7
SP-ASS-70 air speed sensor

I was experiencing random "sensor lost" occurrences after upgrading the RX FW to 2.1.7. On the Frsky download page I saw that there was an update for the FW for the SP-ASS-70 sensor, specifically to "Solve problems with incompatible ACCESS receivers.".
After updating the FW on the ASS-70, the sensor lost messages went away. However, the readings are totally wrong. What should be about 50 kts now reports 18 kts. I did rediscover the sensor, same deal.
Tried a V2 ACCST receiver, same deal. It looks like FrSky screwed up the calibration curve of the sensor with the upgrade (BTW, I double checked, I did use the right FW).
If I blow into the pitot tube, a ASS-70 with the original firmwmare reads 147 kts (the maximum speed). On a ASS-70 with the updated FW it reads 68 kts.
Thinking that it may be a simple matter of a rescaling factor, I played with the ratio factor in the OTX sensor menu. If I set the ratio so that when I blow into the Pitot tube it reads 147 kts, lower values are not
represented correctly (as measured in our lab wind tunnel).

So right now the two speed sensors that I updated are basically useless. Is there anywhere where I can get a copy of the original firmware?

 

[Fireflite88]

Following

 

[HENNY]

I guess your TX is at version v2 rf module firmware.

Try deleting the sensors in the telemetry page and re discover sensors.

 

[ululi1970]

I did delete it and rediscover it, same problem. Also tried it with another ACCESS receiver and with a ACSST V2 receiver. Same problem. It appears to be an issue with the sensor FW itself. I wish there was a way to roll back the upgrade.

 

[HENNY]

I don't believe its an update issue. You can roll back the updates at any time. The RF V1 and V2 are on the FRsky website.

 

[ululi1970]

The problem it's the firmware that runs on the speed sensor, not the firmware that runs on the receiver nor the one that runs on module on the transmitter. On the Frsky website i can only download the firmware that I ended up installing

 

[HENNY]

Are you near Aloft. You could call Wayne and see what he could help you with.

 

[ululi1970]

Unfortunately I am on the other side of the country

 

[MikeB]

I'll ask an obvious question! The download has two files, one for the ASS70, the other for the ASS100. You did flash the one for the ASS70 didn't you?
Then there is the other possibility, have FrSky swapped the names of the files, and the ASS70 file is actually for the ASS100, and vice-versa?

Mike

 

[ululi1970]

Yes, I thought about that. So I did try to flash the ASS100 file. The flash went through, and the sensor was recognized, but when I tested it (blowing), it did not move from 0 kts.

 

[Wayne]

By any chance is your sensor rather old? I'll ask FrSky if they have some ideas..

 

[ululi1970]

It was purchased from you guys in April. Would be nice to have the original firmware available. Btw, somebody else reported the same problem on the GitHub frsky repository. Have not heard from Frsky yet... Maybe you have more clout

 

[Wayne]

I wrote to FrSky about this but have not heard back yet. I flagged it to the main tech that writes the code.

 

[ululi1970]

Thanks.

 

[paolod]

Any updates to this? I am having the same issue. Reports a constant 18knots after firmware upgrade.

 

[ululi1970]

Paolod, they posted a new version of the firmware that fixed the problem for me

ASS-70 - FrSky - Lets you set the limits

www.frsky-rc.com

 

[paolod]

Same issue. Didn’t help.

 

[paolod]

Any updates from anyone?

 

[Wayne]

Checking with FrSky again..