Hey Guys, Anyone else who is using the I2C-PWM Converter for their heavylift upgrade having issues with their Alt hold? If I turn mine on the copter shoots straight up at full power. If I decrease the throttle it will eventually cut all the power and the copter just drops. I have checked all the contacts for the pressure sensor and they all are ok. I will be swapping out the FC to the one that was ORIGINALLY on my copter before. The one I am using now is the one from the gimbal pre-radian so it was never used for flying. Im wondering if there is a defect. I would love to hear your thoughts. Josh
Ah, yes, sir, that's our new "Low Earth Orbit Altitude Hold" feature. I presume there's no method for getting debug output from the converter so you can see what it's doing, Josh? Can you put an oscilloscope on the PWM output to see what happens when you enable AH? Andy.
Josh Take a look at the Altitude tab and see if adjusting the Baro D value. Default I think is 30. Also are you using the Vario Altitude control? If you are i'll give you a scenario that might be what you see. Vario is turned on and expects that the stick will be at a 127 (mid point value). You take off, get to altitude and turn on AH. Copter starts climbing. At hover where is your stick value at hover? If it is much below 127, say 90, then the FC automatically increases to 127 (at least I think that is the logic). Reverse is true when you turn it off. I was running mine using the center spring and had to juggle the throttle a bit when turning AH on and off. But my hover point was close to 127 (50%) throttle. ยท Barometric D (Luftdruck D) o Slows down the oscillation behavior of the height regulator. A high value will increase the influence of the air-pressure on the AH-algorithm. A high value will make the AH more precise, but also a lot more sensitive to wind-gusts.
Josh... after seeing you first mention that you had the multi shooting up when enabling AH, I was a little scared to give it a go. During my last flight before I pulled the FC off in preparation to put the WKM on it, I figured I'd give it one flick for giggles. It sat there just like it had before on that same FC with the stock setup in Vario with the same settings. No weirdness etc, which now makes me think your FC might have issues. Even just normal flight it seems you have shakes and stuff which I am/was not seeing at all. Maybe there is something to this?
Hello Josh, Hardware: There is a very thin, sensitive membrane within the pressure sensor that may be damaged. Also, have a look at the comb "legs" that attach the pressure sensor to the Flight Control board PCB. If one of the legs is cracked it would produce a malfunction in flight. Do you have this sensor encased in a shroud? Here is the part in question that I am referring to: http://www.quadrocopter.com/Pressure-sensor-MPX-4115A_p_80.html Software: I am not familiar with this I2C/PWM converter, but it may be an issue with the travel adjust in the Tool. Greetings, Adam
Josh: If you have a micro-SD card in the MK Navi board, you could look at the GPX files -- they'd show you in a heartbeat whether or not you were getting wacko altimeter readings and therefore Adam's thought re: damaged pressure sensor would be correct. Andy.
Just open up the GPX file with a text editor. There's a header block and a footer block and, in between, a bunch of "track points" that look like this (with different data values between the begin and end tags. The red highlighted values below are the ones to look for. If they're wacko, then the pressure sensors is naffed up. The Altimeter data is shown in units of 5 cm, by the way. So to convert to meters, divide by 20. The <ele>..</ele> data is the elevation from the GPS unit, but that's relative to sea level and is in meters. If you know what your altitude is above sea level you could use the <ele> data to sanity check the <Altimeter> data more or less -- bearing in mind that atmospheric pressure is a rather crude way of getting altitude. I suspect if the air pressure sensor is indeed naffed, you'll be getting very odd readings. The start of the "track point is <trkpt .....> and the end is </trkpt> Holler if you have questions -- or post the GPX file and I'll have a look at it. Andym <trkpt lat="+45.6507562" lon="-122.8231492"> <ele>0.000</ele> <time>2012-10-07T21:18:08Z</time> <sat>7</sat> <extensions> <Altimeter>-3,' '</Altimeter> <Variometer>0</Variometer> <Course>000</Course> <GroundSpeed>3</GroundSpeed> <VerticalSpeed>-1</VerticalSpeed> <FlightTime>3</FlightTime> <Voltage>16.7</Voltage> <Current>25.4</Current> <Capacity>35</Capacity> <RCQuality>209</RCQuality> <RCRSSI>0</RCRSSI> <Compass>305,310</Compass> <NickAngle>000</NickAngle> <RollAngle>000</RollAngle> <MagnetField>100</MagnetField> <MagnetInclination>67,-1</MagnetInclination> <MotorCurrent>14,18,4,18,11,39,6,23,0,0,0,0</MotorCurrent> <BL_Temperature>35,36,35,37,39,46,43,40,0,0,0,0</BL_Temperature> <AvaiableMotorPower>255</AvaiableMotorPower> <FC_I2C_ErrorCounter>000</FC_I2C_ErrorCounter> <AnalogInputs>15,10,15,0</AnalogInputs> <NCFlag>0x81</NCFlag> <Servo>128,128,0</Servo> <WP>----,0,0,0</WP> <FCFlags2>0xc3,0x18</FCFlags2> <ErrorCode>000</ErrorCode> <TargetBearing>000</TargetBearing> <TargetDistance>0</TargetDistance> <RCSticks>0,0,29,-35,0,0,0,0,127,127,127,127</RCSticks> <GPSSticks>0,0,0,'/'</GPSSticks> </extensions> </trkpt>
Just open up the GPX file with a text editor. There's a header block and a footer block and, in between, a bunch of "track points" that look like this (with different data values between the begin and end tags. The red highlighted values below are the ones to look for. If they're wacko, then the pressure sensors is naffed up. The Altimeter data is shown in units of 5 cm, by the way. So to convert to meters, divide by 20. The <ele>..</ele> data is the elevation from the GPS unit, but that's relative to sea level and is in meters. If you know what your altitude is above sea level you could use the <ele> data to sanity check the <Altimeter> data more or less -- bearing in mind that atmospheric pressure is a rather crude way of getting altitude. I suspect if the air pressure sensor is indeed naffed, you'll be getting very odd readings. The start of the "track point is <trkpt .....> and the end is </trkpt> Holler if you have questions -- or post the GPX file and I'll have a look at it. Andym <trkpt lat="+45.6507562" lon="-122.8231492"> <ele>0.000</ele> <time>2012-10-07T21:18:08Z</time> <sat>7</sat> <extensions> <Altimeter>-3,' '</Altimeter> <Variometer>0</Variometer> <Course>000</Course> <GroundSpeed>3</GroundSpeed> <VerticalSpeed>-1</VerticalSpeed> <FlightTime>3</FlightTime> <Voltage>16.7</Voltage> <Current>25.4</Current> <Capacity>35</Capacity> <RCQuality>209</RCQuality> <RCRSSI>0</RCRSSI> <Compass>305,310</Compass> <NickAngle>000</NickAngle> <RollAngle>000</RollAngle> <MagnetField>100</MagnetField> <MagnetInclination>67,-1</MagnetInclination> <MotorCurrent>14,18,4,18,11,39,6,23,0,0,0,0</MotorCurrent> <BL_Temperature>35,36,35,37,39,46,43,40,0,0,0,0</BL_Temperature> <AvaiableMotorPower>255</AvaiableMotorPower> <FC_I2C_ErrorCounter>000</FC_I2C_ErrorCounter> <AnalogInputs>15,10,15,0</AnalogInputs> <NCFlag>0x81</NCFlag> <Servo>128,128,0</Servo> <WP>----,0,0,0</WP> <FCFlags2>0xc3,0x18</FCFlags2> <ErrorCode>000</ErrorCode> <TargetBearing>000</TargetBearing> <TargetDistance>0</TargetDistance> <RCSticks>0,0,29,-35,0,0,0,0,127,127,127,127</RCSticks> <GPSSticks>0,0,0,'/'</GPSSticks> </extensions> </trkpt>
Hi Josh: The only thing that seems a bit off is the compass -- did you re-cal the compass before you flew? This shouldn't account for AH problems, though -- but I didn't see any places in the data where you enabled AH. Is this correct? That could, of course, explain one or two things -- if you thought you were enabled AH but you were not.... Andy.
I don't fly with the compass at all and have it disabled in MK Tools so I haven't calibrated it. On my old setup it wasn't calibrated either and I never had an issue with it. Let me find another file that I know AH was tested... Thought I used it on that flight. Josh
How come the Carefree flag is set for the entire flight, Josh? This one was from your original non-heavy lifter flight right? The Motor Currents and BL Temps are shown and the voltage starts out at 14.8. What am I looking for? Andy.
Andy, I just re-downloaded the file and looked at it. It is my latest flight and is from my HL copter... any possibility of you opening the wrong file? This one should have AH on the entire flight and is only 40 seconds. I was going to have you look and see if there was an odd reading on the Pressure reading or not. Im not sure what im looking for. Josh
Hmm. OK. I redownloaded it. I think I got the correct file. It's only 7 seconds long. At second 4, the throttle is at about 3/4 of maximum, and the bird goes from ground level up to five feet, then by second 6 you're almost at maximum throttle and the bird is at 8.5, then if comes back to 2.29 feet by second 7, and it's at 2.95 feet by second 8, when you move the left stick back and to the left. No odd readings from the altimeter....but I fret this is obviously not the 40 second flight to which you're referring. The date/time stamp on the GPX file is 1/8/2013 at 12:20:35 pm -- but that's Pacific Time (MK_GPXTOOL corrects for local time zone). The raw data shows: <time>2013-01-08T20:20:32Z</time> (Z = Zulu time, aka GMT.) Andy.
Weird... I decided to swap out the FC's anyway and it looks like the sensor might have been bad. I looked at the "Height Value" in MK tools and with the FC that I was having issues with the height value was reading 70-80. The new FC is I just put on is reading 0-2 and is reacting correctly to changes to moving the copter up and down inside (I was just lifting the copter in my apt and watching the scope on MKTools). Ill be flying tomorrow to see how it does... Josh
Hi Josh: The good news is that you can get replacement pressure sensors. http://www.quadrocopter.com/Pressure-sensor-MPX-4115A_p_80.html Andy.