The MARSA54 Government Shutdown Sale!

[curtisheisey]

John,

Hi, what are the hole centers on the
a) MrfBridge and
b) Forthcoming RF Gyro

Tx.

 

[curtisheisey]

Oh, right, as Mike said, a min alt condition would be good as well.

I would vote for either:

event triggered if
time > t_burnout + t1 &
time < t_burnout + t2
angle < maxTilt angle &
alt > altMin

or

event triggered if
time > t_burnout + t1 &
speed > speedMin &
angle < maxTilt angle &
alt > altMin

 

[jderimig]

I will send hole centers tonight.

Min alt is already there but can be tricky if staging around Mach as the baro altitude alone cannot be trusted. There is already a global 200 ft lockout for ground safety reasons.

 

[mikec]

Min alt is already there but can be tricky if staging around Mach as the baro altitude alone cannot be trusted.

I always set my min alt to about 75% of what I actually expect from sims at my burnout+delay, so hopefully that provides some margin.

FWIW, rather than a max time I'd be satisfied if motor timer events were simply inhibited after apogee. If you add too many parameters then the possibility of user error starts to creep in.

I know it's a fair amount of effort, but it would be great if you documented the exact logic that goes into the channel firing conditions for safety review (this thread has taken us a long way toward that goal). One of the things I like about the Raven is that most of the conditions are explicitly set by the user, which makes the user do more work but is nicely transparent. Not saying you should do that but it's an example.

 

[jderimig]

I agree. I started to make some codespace to allow a menu where the inhibit options are explicit .

I always set my min alt to about 75% of what I actually expect from sims at my burnout+delay, so hopefully that provides some margin.

FWIW, rather than a max time I'd be satisfied if motor timer events were simply inhibited after apogee. If you add too many parameters then the possibility of user error starts to creep in.

I know it's a fair amount of effort, but it would be great if you documented the exact logic that goes into the channel firing conditions for safety review (this thread has taken us a long way toward that goal). One of the things I like about the Raven is that most of the conditions are explicitly set by the user, which makes the user do more work but is nicely transparent. Not saying you should do that but it's an example.

 

[mikec]

My reading of the Marsa33 documentation for timer-mtr events is that if you set mode 1 or mode 2 (delay from launch/burnout) and you have a non-zero value for mode 3 (alt-up) and set the altimeter to mode 1 or 2, that lockout value is used even though nothing about it is displayed on the LCD at power-up. Correct?

What happens if you set mode 3 as the mode? Does it fire when it reached that altitude regardless of the delay values in mode 1 or 2, or are you just not supposed to do that?

If you have a channel configured for something but no continuity is detected on that channel, the Marsa beeps once instead of twice after power-on, but does it still try to fire that channel and the other channels appropriately during flight?

I'm trying my first Marsa flight this weekend and just want to be sure.

 

[Performance nut]

I realize that we aren't in shutdown anymore though this thread has been updating. So I'd kick myself if I didn't ask. Is the sale over and this is now a product support discussion?

 

[jderimig]

My reading of the Marsa33 documentation for timer-mtr events is that if you set mode 1 or mode 2 (delay from launch/burnout) and you have a non-zero value for mode 3 (alt-up) and set the altimeter to mode 1 or 2, that lockout value is used even though nothing about it is displayed on the LCD at power-up. Correct?

Mike,

Yes, the altitude set in the mode 3 altitude field must be reached when the mode 1 or 2 timer is invoked.

However if you are using a Tilt Module there is no altitude lockout in the firmware version 25B. There will be an imminent firmware upgrade when both the altitude and tilt conditions must be satisfied.

What happens if you set mode 3 as the mode? Does it fire when it reached that altitude regardless of the delay values in mode 1 or 2, or are you just not supposed to do that?

Yes if you are in mode 3, then just the alt up value is the trigger. The mode you are in is the mode in which you exit the programming sequence. For example to set the altitude lockout in mode 1 or 2, you must return to the mode 1 or 2 menu after you set the altitude in mode 3. To avoid error, first set the altitude in mode 3 and then program mode 1 or 2 if you want mode 1 or 2.

If you have a channel configured for something but no continuity is detected on that channel, the Marsa beeps once instead of twice after power-on, but does it still try to fire that channel and the other channels appropriately during flight?

If there is a continuity failure detected all the channels will attempt to fire with the EXCEPTION of any channel designated as a Timer-Mtr. Time-Mtr channels are inhibited with any detection of an anomalous condition.

 

[jderimig]

I realize that we aren't in shutdown anymore though this thread has been updating. So I'd kick myself if I didn't ask. Is the sale over and this is now a product support discussion?

Alas the sale is over.

 

[mikec]

If there is a continuity failure detected all the channels will attempt to fire with the EXCEPTION of any channel designated as a Timer-Mtr. Time-Mtr channels are inhibited with any detection of an anomalous condition.

I thought there was no continuity checking on timer-mtr? Manual says "Timer-MTR is the same as Timer except Timer-MTR does not continuity test during POST". When does it do the continuity check? Or maybe you're saying that if some other channel doesn't have continuity timer-mtr channels never fire. I guess that makes sense.

 

[jderimig]

I thought there was no continuity checking on timer-mtr? Manual says "Timer-MTR is the same as Timer except Timer-MTR does not continuity test during POST". When does it do the continuity check? Or maybe you're saying that if some other channel doesn't have continuity timer-mtr channels never fire. I guess that makes sense.

Yes, a Timer-Mtr channel cannot cause a failed continuity check condition. Other events programmed for a channel, including 'Off', need to be consistent with there continuity status.

 

[curtisheisey]

I have a Q about the RF pyro module. The instructions say not to program two events with 1/2 sec of each other. If I want to simultaneously airstart a pair of motors, can I tie both to one channel? These will be CTI type ignitors.

 

[jderimig]

I have a Q about the RF pyro module. The instructions say not to program two events with 1/2 sec of each other. If I want to simultaneously airstart a pair of motors, can I tie both to one channel? These will be CTI type ignitors.

Yes. I would suggest series wiring if only stringing 2.

 

[TandemDwarf3410]

If they did this in December/January 2018, I would get a free motor and 125 dollars if I got one on the last day.

 

[JackC]

Oh, you are supposed to fly the 33 with the LCD screen? Good to know. I just thought it was for use on the ground.

 

[AdAstraPerAspera]

Oh, you are supposed to fly the 33 with the LCD screen? Good to know. I just thought it was for use on the ground.

Huh? No. I don't think that's the case.

 

[jderimig]

Oh, you are supposed to fly the 33 with the LCD screen? Good to know. I just thought it was for use on the ground.

No. Take the screen off for flight.

 

[JackC]

No. Take the screen off for flight.

Got it! Thanks!

 

[AdAstraPerAspera]

The whole idea is that the screen comes off, so that the altimeter is smaller, the screen doesn't get broken in flight, and you only need one screen for multiple altimeters.

 

[jsdemar]

No. Take the screen off for flight.

I flew just the screen and it didn't display anything.