Arming issues setting up new frame

I’m setting up a new 250 heli and I can’t arm due to motor interlock. I’ve disabled arming checks for bench testing and also switched interlock from channel 8 to channel 7 and still no dice. My radio is outputting around 950 on the low end for both channels and 2000 on high end. In Mission Planner output page channel 8 just jitters a small amount, won’t move the full range no matter what I do, however, when I switched interlock over to channel 7 MP showed the full range but still no arming. Can anyone kindly look at my parameters attached and see what I’m missing? I’ve watched all the videos and read the wiki, thank you in advance.

heliparams24.param (13.9 KB)

From looking through your params, this appears to be an old version of firmware. Please upgrade to the latest version.

Copy that Bill, will do and I’ll try it again.

I did update to the latest version but no changes except for a collective pitch warning, I’m still trying to figure out why channel 8 in radio calibration just jitters a small amount constantly, hangs around 17 or 1800 and doesn’t follow my radio inputs at all therefore I can’t arm the Heli on the bench. I remember going through the same thing 5 years ago but can’t remember what the fix was. As stated I’ve read through the wiki and watched the videos but they don’t help. Ive pretty much used up all the searches for motor interlock, can’t find anyone that has the similar problem on channel 8, thank you.

Please post your new params. You will need to follow the swashplate set up procedure to set the H_COL_ANG_MIN and H_COL_ANG_MAX. Those are very important.

newheli1.param (18.1 KB)
Here are the new parameters, I went through the swashplate setup as well.

Hello Mac!

I just had a look at your new parameter file and it looks like your RC8 min/max only has a range between 1749 and 1866 PWM.

I would check to make sure that channel has -100/+100 endpoints in your radio and then re-calibrate (both in your radio and in MP).

As it states here, “The transmitter channel on which the motor interlock is set requires the PWM to be low (<1200 PWM) for motor interlock disabled (throttle hold on) and above 1200 PWM for motor interlock enabled (throttle hold off).”

Your FC is currently not seeing less than 1200 PWM and believes your motor interlock is enabled (throttle hold off), and will not let you arm in that unsafe condition.

3 Likes

Hi Mike, thanks for the help! I can’t figure out why channel 8 is outputting those values, I’ve switched radios and I’m looking at the settings now. I haven’t changed anything on channel 8 in my radio so I’m wondering if I have a receiver issue (frsky XM+ receiver) thanks again.

If your radio shows a reasonable channel output, but MP doesn’t, is it possible that you may have simply forgotten to flip that channel’s switch during RC calibration in MP?

Thanks again for all the help, I have been working with this for a while now and have gotten my channel 8 working properly. I recently changed radios and maybe that was the problem but I also switched to using qgroundcontrol and that seems easier at the time being for my setup. I just need to find the procedure for setting max cyclic pitch angle (can’t find the tutorial video that cover cyclic pitch) I’ve setup min max collective and leveled the swashplate however :slight_smile:

Glad you worked it out Mac! :grinning:

You can find some details on setting up max cyclic around 6:50 in Bill Geyer’s traditional heli collective curves tutorial, second video down on this page.

You would have the blades in line with the aircraft in the longitudinal direction (nose/tail), collective at zero, null your pitch gauge, move your roll stick (lateral cyclic) fully, then read maximum cyclic deflection.

I would adjust the value to correspond to an angle in the range recommended in your model’s manual.

As an example, the default 2500 was a bit much for my Align 450L.

1800 gives me around 8° max cyclic.