RPM readings just died!

nickyd · 06-21-2011, 07:09 AM

This is not my week!

On the plus side I got my eagle tree brushless rpm sensor working with the sk720 in governor mode and replay agreed with tach'd rpm. yippee really stable too.

On the minus side, a few seconds onto the last flight the rpm reading was just ramping up and then dropped to zero for the rest of the flight.(in playback and sk-plot)
The heli flew ok during the actual flight although it did seem to have dropped headspeed.
I guess the sk720 was trying to govern when no signal was actually arriving from the sensor .

Connectors and wires all look ok. I did have the sensor fitted next to the esc. maybe it overheated??

Helos4me · 06-21-2011, 08:27 AM

Nick, not too familar with the electric side but the SK seemed to function as advertised. When the sensor went south, the sk dropped to the 40% curve you put in when setting up with the wizard, I'm assuming you were in normal rpm. That would be why the rpm dropped. Why the sensor went out

nickyd · 06-21-2011, 08:31 AM

Hi. I was in idle when this happened. I have confirmed with the sk-plot which shows 100% throttle input.
My start up is to put the heli in idle. move collective to centre (zero degrees pitch) and flick throttle hold.

Will look it over this evening and dis-engage governor until the rpm readings work again......hopefully.

Castel · 06-21-2011, 09:27 AM

The SK went to safe mode which happens when the rpm sensor signal is lost. It happened to me. Check with a multimeter on the bench that the + and - soldered pins in the sensor board are getting the expected voltage. Check for resistance/continuity on the signal and sensing pins basically making sure that all connections are still ok, in my case the signal wire from sensor to SK had broken.

nickyd · 06-21-2011, 09:40 AM

Hi Castel,

Will probe with the dvm later.

Cheers,

Nick.

georgi UK · 06-21-2011, 12:14 PM

=] Nick, with gov disabled and RPM sensor checked in the software with a gear ratio, the playback will determine if the sensor is alive and kicking.

georgi UK

nickyd · 06-22-2011, 12:28 AM

Took the unit out and tested it. All seems ok. Fitted again and rpms are now working.

may be an intermittent faulty wire. will replace the cable.

Thanks.

06-21-2011, 07:09 AM	#1
nickyd Registered Users Join Date: Feb 2010 Location: Switzerland	RPM readings just died! This is not my week! On the plus side I got my eagle tree brushless rpm sensor working with the sk720 in governor mode and replay agreed with tach'd rpm. yippee really stable too. On the minus side, a few seconds onto the last flight the rpm reading was just ramping up and then dropped to zero for the rest of the flight.(in playback and sk-plot) The heli flew ok during the actual flight although it did seem to have dropped headspeed. I guess the sk720 was trying to govern when no signal was actually arriving from the sensor . Connectors and wires all look ok. I did have the sensor fitted next to the esc. maybe it overheated?? __________________ Nick Mini Titan E325 V1, SK720, FBL , Scorpion HK 2221-8, Ice Lite 50, CC 10amp BEC, MKS DS95 ,DS95i , KBDD 61mm Tail Blades, 2200mah lipo. DX6i . AP with Panasonic LX3. Sport Flyer

06-21-2011, 08:27 AM	#2
Helos4me Registered Users Join Date: May 2008 Location: San Diego, CA	Nick, not too familar with the electric side but the SK seemed to function as advertised. When the sensor went south, the sk dropped to the 40% curve you put in when setting up with the wizard, I'm assuming you were in normal rpm. That would be why the rpm dropped. Why the sensor went out __________________ 700e DFC / KDE 700XF-495 and mount CC Ice2 HV120 / BEC Pro Sk 720 Flybarless / Batt Bus

06-21-2011, 08:31 AM	#3
nickyd Registered Users Thread Starter Join Date: Feb 2010 Location: Switzerland	Hi. I was in idle when this happened. I have confirmed with the sk-plot which shows 100% throttle input. My start up is to put the heli in idle. move collective to centre (zero degrees pitch) and flick throttle hold. Will look it over this evening and dis-engage governor until the rpm readings work again......hopefully. __________________ Nick Mini Titan E325 V1, SK720, FBL , Scorpion HK 2221-8, Ice Lite 50, CC 10amp BEC, MKS DS95 ,DS95i , KBDD 61mm Tail Blades, 2200mah lipo. DX6i . AP with Panasonic LX3. Sport Flyer

06-21-2011, 09:27 AM	#4
Castel Registered Users Join Date: Feb 2011 Location: Portland, OR	The SK went to safe mode which happens when the rpm sensor signal is lost. It happened to me. Check with a multimeter on the bench that the + and - soldered pins in the sensor board are getting the expected voltage. Check for resistance/continuity on the signal and sensing pins basically making sure that all connections are still ok, in my case the signal wire from sensor to SK had broken. __________________ Compass 6HV - FBL SK-720 \| JR 8917HV \| Outrage BL9188 HV \| HW 70A ESC \| WR Super-BEC \| KBDD \| DX8

06-21-2011, 09:40 AM	#5
nickyd Registered Users Thread Starter Join Date: Feb 2010 Location: Switzerland	Hi Castel, Will probe with the dvm later. Cheers, Nick. __________________ Nick Mini Titan E325 V1, SK720, FBL , Scorpion HK 2221-8, Ice Lite 50, CC 10amp BEC, MKS DS95 ,DS95i , KBDD 61mm Tail Blades, 2200mah lipo. DX6i . AP with Panasonic LX3. Sport Flyer

06-21-2011, 12:14 PM	#6
georgi UK Registered Users Join Date: Mar 2007 Location: United Kingdom	=] Nick, with gov disabled and RPM sensor checked in the software with a gear ratio, the playback will determine if the sensor is alive and kicking. georgi UK

06-22-2011, 12:28 AM	#7
nickyd Registered Users Thread Starter Join Date: Feb 2010 Location: Switzerland	Took the unit out and tested it. All seems ok. Fitted again and rpms are now working. may be an intermittent faulty wire. will replace the cable. Thanks. __________________ Nick Mini Titan E325 V1, SK720, FBL , Scorpion HK 2221-8, Ice Lite 50, CC 10amp BEC, MKS DS95 ,DS95i , KBDD 61mm Tail Blades, 2200mah lipo. DX6i . AP with Panasonic LX3. Sport Flyer

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