Micro level preview

I must have missed something on this. All I saw was a lighted electronic
screen in a dash of a GMC. Were there more pictures? Can't tell much from
what I see.
Jim Hupy
Salem, Or
78 GMC Royale 403

> Simply magnificent! Can't wait till they are available in production form.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
> I must have missed something on this. All I saw was a lighted electronic
> screen in a dash of a GMC. Were there more pictures? Can't tell much from
> what I see.
> Jim Hupy
> Salem, Or
> 78 GMC Royale 403

>
> > Simply magnificent! Can't wait till they are available in production form.
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

Yes there are more pictures and description in previous messages
--
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
69 Vette
29 Dodge
 
Keith -

"Steve - I could make the manual mode have a lower limit that you can calibrate in. Thats a great idea.
Just set the height to the lowest level desired and then hit the calibrate button."

I've been contemplating... I'm hoping the configuration settings are stored in non-volatile RAM. I often disconnect all batteries for storage -
wouldn't want to have to re-calibrate every time.

I really like it - especially the horizon leveling. Can't wait to tell my big diesel SOB friends with auto-level hydraulic jacks - "yea - I can do
that too."

Thanks,
SW
 
> Keith -
>
> "Steve - I could make the manual mode have a lower limit that you can calibrate in. Thats a great idea.
> Just set the height to the lowest level desired and then hit the calibrate button."
>
> I've been contemplating... I'm hoping the configuration settings are stored in non-volatile RAM. I often disconnect all batteries for storage -
> wouldn't want to have to re-calibrate every time.
>
> I really like it - especially the horizon leveling. Can't wait to tell my big diesel SOB friends with auto-level hydraulic jacks - "yea - I can
> do that too."
>
> Thanks,
> SW

Can they do it from outside with an RF remote?

--
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
69 Vette
29 Dodge
 
> Keith -
>
> I've been contemplating... I'm hoping the configuration settings are stored in non-volatile RAM. I often disconnect all batteries for storage -
> wouldn't want to have to re-calibrate every time.

oops I didn't read everything.
yes the calibration parameters are stored in EEPROM, no power required

I just added the code to set the low limit, wasn't too bad, now I just have to test it.

One problem, the sensors are very nonlinear due to the mechanics, that means they are very accurate at ride height but terrible at full up and full
down.
So the low limit may not work due to mechanical geometry. cosine error basically.

But yes the calibration parameters are stored in FLASH, no power required
--
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
69 Vette
29 Dodge
 
http://www.gmcmhphotos.com/photos/g6645-ride-height.html

bdub

-----Original Message-----
From: Gmclist On Behalf Of James Hupy
Sent: Friday, October 7, 2016 4:16 PM
Subject: Re: [GMCnet] Micro level preview

I must have missed something on this. All I saw was a lighted electronic screen
in a dash of a GMC. Were there more pictures? Can't tell much from what I see.
 
Keith,

Very nice work!

I'm curious about your chart of Ride Height Data. I presume that's the raw
data from the ride height sensors. Otherwise I'd expect to see only binary
signals to the valves.

How much delay (hysteresis) do you have built into the system (like GMC's
4s.-18s.)? Is that operator adjustable as a configuration setting? I ask
primarily because it seems to me that the hysteresis needed depends upon
the characteristics of the air bags and the available pressure and volume
from the compressor. If the system is set up for bags requiring high
pressure and a slow compressor, the delay would presumably be shorter than
for a low bag pressure/fast compressor vehicle. A setting suitable for the
former might make the latter too sensitive to dynamic loads.

Do you intend to preserve GMC's long delay or to shorten it for "real time"
operation?

Still Curious Old Cat. :-)

Ken H.

> Finally ready to show off the working prototype
>
> Introducing Microlevel.
> Totally electronic
> microprocessor controlled
> True height measuring sensors
> Horizon leveling
> RF remote control
> Replaces PowerLevel and ElectroLevel
>
> http://www.gmcmhphotos.com/photos/data/6645/medium/CAM00345.jpg
>
> --
> Keith Vasilakes
> Mounds View. MN
> 75 ex Royale GMC
> 69 Vette
> 29 Dodge
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
> Keith,
>
> Very nice work!
>
> I'm curious about your chart of Ride Height Data. I presume that's the raw
> data from the ride height sensors. Otherwise I'd expect to see only binary
> signals to the valves.
>
> How much delay (hysteresis) do you have built into the system (like GMC's
> 4s.-18s.)? Is that operator adjustable as a configuration setting? I ask
> primarily because it seems to me that the hysteresis needed depends upon
> the characteristics of the air bags and the available pressure and volume
> from the compressor. If the system is set up for bags requiring high
> pressure and a slow compressor, the delay would presumably be shorter than
> for a low bag pressure/fast compressor vehicle. A setting suitable for the
> former might make the latter too sensitive to dynamic loads.
>
> Do you intend to preserve GMC's long delay or to shorten it for "real time"
> operation?
>
> Still Curious Old Cat. :)
>
> Ken H.

Ken, yes that raw analog data from the sensors, The controller only uses the sensors in travel mode, in manual or camp they are ignored ( except for
the low limit feature I'm thinking about adding ) It's only there for curiosity, I did spend a lot of time looking at charts and state change events
if you are really a sucker for punishment

there are no user settable parameters, everything is fixed.
Except low limit, travel height and the horizon level values, they are calibrated.
If I did feel the need to vary the value the system would measure the system response time and do an auto calibrate.
Theres no way the average person would be able to do that without mucho training

But the algorithm is quite complex, it's running a state machine, and multiple filters, both FIR and IIR.
When it's close it actually pulses the valve to get right on.
When you first put it into travel it uses a fast filter, then once it reaches ride height it goes to a very very slow filter. This allows it to come
up to height fast then not adjust on cloverleafs or grade changes. the slow rate is in the minutes range.
It also has different reaction times if it's filling vs if it's already at ride height.
It's control like this that make using a micro better than a mechanical switch!

The hysteresis is much better than the stock system, I measure it in ADC counts and don't have a good correlation to inches, I need to do that.
It's +- 10 ADC counts on a 10bit ADC, but the height is measured as sin(adc) 0' to 90'
someone do the trig for me ha ha

The pressure in the bags shouldn't make any difference, but I do want to test on a sully bag and a 4 bag to see if anything needs to be tweeked.
I really don't think the system in use will have any effect on the algorithm, the only delay Ive seen is the delay caused by the air lines.
If you run big valves and big airlines the residual pressure in the line could cause overshoot/undershoot as the valves open and close but the air
line still has to equalize.

This system is targeted directly at the GMC it's not a general purpose solution.

--
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
69 Vette
29 Dodge
 
Keith,

Great response. You've obviously covered all the points of concern I had.
And implemented the system with modern algorithms rather than the more
analog approach my 40 year old education would have dictated. :-)

Thanks for modernizing the GMC.

Ken H.

> ...

Ken, yes that raw analog data from the sensors, The controller only uses
> the sensors in travel mode, in manual or camp they are ignored ( except for
> the low limit feature I'm thinking about adding ) It's only there for
> curiosity, I did spend a lot of time looking at charts and state change
> events
> if you are really a sucker for punishment
> ...
 
> > Keith,
> >
> > Very nice work!
> >
> > I'm curious about your chart of Ride Height Data. I presume that's the raw
> > data from the ride height sensors. Otherwise I'd expect to see only binary
> > signals to the valves.
> >
> > How much delay (hysteresis) do you have built into the system (like GMC's
> > 4s.-18s.)? Is that operator adjustable as a configuration setting? I ask
> > primarily because it seems to me that the hysteresis needed depends upon
> > the characteristics of the air bags and the available pressure and volume
> > from the compressor. If the system is set up for bags requiring high
> > pressure and a slow compressor, the delay would presumably be shorter than
> > for a low bag pressure/fast compressor vehicle. A setting suitable for the
> > former might make the latter too sensitive to dynamic loads.
> >
> > Do you intend to preserve GMC's long delay or to shorten it for "real time"
> > operation?
> >
> > Still Curious Old Cat. :)
> >
> > Ken H.
>
>
> Ken, yes that raw analog data from the sensors, The controller only uses the sensors in travel mode, in manual or camp they are ignored ( except
> for the low limit feature I'm thinking about adding ) It's only there for curiosity, I did spend a lot of time looking at charts and state change
> events if you are really a sucker for punishment
>
> there are no user settable parameters, everything is fixed.
> Except low limit, travel height and the horizon level values, they are calibrated.
> If I did feel the need to vary the value the system would measure the system response time and do an auto calibrate.
> Theres no way the average person would be able to do that without mucho training
>
> But the algorithm is quite complex, it's running a state machine, and multiple filters, both FIR and IIR.
> When it's close it actually pulses the valve to get right on.
> When you first put it into travel it uses a fast filter, then once it reaches ride height it goes to a very very slow filter. This allows it to
> come up to height fast then not adjust on cloverleafs or grade changes. the slow rate is in the minutes range.
> It also has different reaction times if it's filling vs if it's already at ride height.
> It's control like this that make using a micro better than a mechanical switch!
>
> The hysteresis is much better than the stock system, I measure it in ADC counts and don't have a good correlation to inches, I need to do that.
> It's +- 10 ADC counts on a 10bit ADC, but the height is measured as sin(adc) 0' to 90'
> someone do the trig for me ha ha
>
> The pressure in the bags shouldn't make any difference, but I do want to test on a sully bag and a 4 bag to see if anything needs to be tweeked.
> I really don't think the system in use will have any effect on the algorithm, the only delay Ive seen is the delay caused by the air lines.
> If you run big valves and big airlines the residual pressure in the line could cause overshoot/undershoot as the valves open and close but the air
> line still has to equalize.
>
>
> This system is targeted directly at the GMC it's not a general purpose solution.

Ya, you really should test it on a sully type system. It could be easy to extend the bags with excess pressure beyond their design, so might be nice
to have a upper limit, so as to not accidentally apply so much pressure that the bags would separate from the cones and just blow up. Also, when the
system is set on travel, does it set height based on position relative to the frame or on a horizon line. If based on horizon, the long climb west to
east up the Eisenhower pass might make it try to compensate leveling for horizon and over extend the bags. Just wondering is all. Nice system
though!!
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.
 
What happens on a power level system when in manual mode?
Does the sully bag over extend and fail if you raise it too far?

In travel mode it uses sensors that measure relative to the frame, just like the stock system, just more accurate.

>
> Ya, you really should test it on a sully type system. It could be easy to extend the bags with excess pressure beyond their design, so might be nice
> to have a upper limit, so as to not accidentally apply so much pressure that the bags would separate from the cones and just blow up. Also, when the
> system is set on travel, does it set height based on position relative to the frame or on a horizon line. If based on horizon, the long climb west to
> east up the Eisenhower pass might make it try to compensate leveling for horizon and over extend the bags. Just wondering is all. Nice system
> though!!
> --
> Larry
> 78 Royale w/500 Caddy
> Menomonie, WI.
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Max rated pressure of the fi 9294 is 100psi. Max lift is achieved long
before that pressure is reached (typically below 65psi). The lift rate from
inflation is quicker with my system and the 9294 bag than the oem bag.
Also, the oe bag continues to grow out both ends very gradually as
pressures increase. When the 9294 bag reaches max lift it stops extending
rather abruptly which is easy to feel if you are paying attention while
leveling. Since there is a lot more "drop" available than "lift" from ride
height, leveling is a lot easier to achieve if the coach is maneuvered
around the camp site until the front end is low compared to the rear at
travel height then the rear lowered to match the front. That said I have
never had a failure reported to me from overinflation.

Sully
77 eleganza 2
Seattle

> What happens on a power level system when in manual mode?
> Does the sully bag over extend and fail if you raise it too far?
>
> In travel mode it uses sensors that measure relative to the frame, just
> like the stock system, just more accurate.
>
>
> >
> > Ya, you really should test it on a sully type system. It could be easy
> to extend the bags with excess pressure beyond their design, so might be
> nice
> > to have a upper limit, so as to not accidentally apply so much pressure
> that the bags would separate from the cones and just blow up. Also, when the
> > system is set on travel, does it set height based on position relative
> to the frame or on a horizon line. If based on horizon, the long climb west
> to
> > east up the Eisenhower pass might make it try to compensate leveling for
> horizon and over extend the bags. Just wondering is all. Nice system
> > though!!
> > --
> > Larry
> > 78 Royale w/500 Caddy
> > Menomonie, WI.
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
> What happens on a power level system when in manual mode?
> Does the sully bag over extend and fail if you raise it too far?
>
> In travel mode it uses sensors that measure relative to the frame, just like the stock system, just more accurate.
>
>
> >
> > Ya, you really should test it on a sully type system. It could be easy to extend the bags with excess pressure beyond their design, so might
> > be nice
> > to have a upper limit, so as to not accidentally apply so much pressure that the bags would separate from the cones and just blow up. Also,
> > when the
> > system is set on travel, does it set height based on position relative to the frame or on a horizon line. If based on horizon, the long climb
> > west to
> > east up the Eisenhower pass might make it try to compensate leveling for horizon and over extend the bags. Just wondering is all. Nice
> > system
> > though!!
> > --
> > Larry

I don't know what the max pressure is, but our systems are capable of up to 150-lbs I think, and if pushed to that limit, I just wonder what would
happen. I have inadvertently extended the bags to 75lbs with no problems. Just after about 60 lbs there is no more extension left in the bag at our
weights, so it just kinda pulls at the seam where it attaches to the cone.
--
Larry
78 Royale w/500 Caddy
Menomonie, WI.
 
> I don't know what the max pressure is, but our systems are capable of up to 150-lbs I think, and if pushed to that limit, I just wonder what would
> happen. I have inadvertently extended the bags to 75lbs with no problems. Just after about 60 lbs there is no more extension left in the bag at
> our weights, so it just kinda pulls at the seam where it attaches to the cone.

If over pressure is a concern readjust compressor cutout pressure. Or better yet install a pressure regulator between the air tank and the leveling
system.
--
Steve Southworth
1974 Glacier TZE064V100150 (for workin on)
1975 Transmode TZE365V100394 (parts & spares)
Palmyra WI
 
If you continue to pressure the bags past the upper limit, it will blow Bilstein shock seals. I blew two of them before I learned better. The upper
limit is the shocks.

Bilstein will NOT warranty shocks blown that way and will instead send you a copy of the GMC manual entry on proper jacking.

I do not think this is a problem on KYB shocks. At least I have not heard of this with KYBs.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
I think I'm going to say that if you have sully bags, and over pressure is as problem, you should lower your supply pressure.
Any other solution is questionable
Because, it is still possible to over pressure the bags and I can't prevent it just by looking at height.
--
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
69 Vette
29 Dodge
 
G'day,

MM X-7525 / Section 4 - Rear Suspension / Page 4-6 / Trouble Shooting Chart / Correction 5. Adjust pressure switch settings to
operate at 100 - 120 psi range.

IIRC the relief valve in Double Trouble's PowerLevel air tank is set at 140 psi (as measured on the 2" gage).

I'll bet dollars to donuts that the OEM bags will take 150% of that (210psi) without any problem and possibly more as that would be
a prudent design point.

Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
 
Ken / Keith,

I stumbled on to this researching the pressure question, I have no idea if it is relevant to your question but thought it might be
helpful.

Ref: MM X-7525 / Section 4 - Rear Suspension / Page 4-25 / Paragraph - Time Delay Check / Preliminary Procedures:

After the valve lever gaps have been adjusted, to a time delay check. A 4 to 18 seconds delay from the closing of one valve to the
opening of the other is recommended. Also, valves should close from full-open position within 4 seconds.

Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Ken Henderson
Sent: Monday, October 10, 2016 7:40 AM
To: gmclist
Subject: Re: [GMCnet] Micro level preview

Keith,

Very nice work!

I'm curious about your chart of Ride Height Data. I presume that's the raw
data from the ride height sensors. Otherwise I'd expect to see only binary
signals to the valves.

How much delay (hysteresis) do you have built into the system (like GMC's
4s.-18s.)? Is that operator adjustable as a configuration setting? I ask
primarily because it seems to me that the hysteresis needed depends upon
the characteristics of the air bags and the available pressure and volume
from the compressor. If the system is set up for bags requiring high
pressure and a slow compressor, the delay would presumably be shorter than
for a low bag pressure/fast compressor vehicle. A setting suitable for the
former might make the latter too sensitive to dynamic loads.

Do you intend to preserve GMC's long delay or to shorten it for "real time"
operation?

Still Curious Old Cat. :-)

Ken H.

> Finally ready to show off the working prototype
>
> Introducing Microlevel.
> Totally electronic
> microprocessor controlled
> True height measuring sensors
> Horizon leveling
> RF remote control
> Replaces PowerLevel and ElectroLevel
>
> http://www.gmcmhphotos.com/photos/data/6645/medium/CAM00345.jpg
>
> --
> Keith Vasilakes
> Mounds View. MN
> 75 ex Royale GMC
> 69 Vette
> 29 Dodge
 
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