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Radio - Servo - Gyro - Gov - Batt > Problem using 94758Z servos on eCCPM - NEW FINDINGS!
 
 
kirk
Veteran
Location: Thornton, Colorado

I3DM

You may want to search thru this thread or contact MarkF (I think) from the thread. If I remember correctly they were doing tests on the airtronics PCM Rx's and discovered something different about the power bus and reset voltage of the RX that could cause the issues you are describing. (one of the guys on the thread bought one of my PCM rx's and used it for some of the tests)

http://runryder.com/helicopter/t734...ht=homebrew+PCM

Wish I could help further!!!

From my experence I believe you are drawing more current than the power bus of the Rx is designed for causing the Rx to reset. Like I stated earlier we ran into this issue with a 40% carden running duel PCM Rx's (One side is running 3 8611's, 2 8411's, a throttle servo, and a couple of matchboxs). We changed over to JR rx's and have not had any problems since. Also note that the loads on the servos and Rx are much greater in the air so if it seems fine on the bench it might not be okay in the air.


Kirk
03-11-2005 Over year old.
 
 
I3DM
rrProfessor
Location: Israel

actually, the loads on an eCCPM system are not as hard as on mCCPM, since all 3 servos are working together, but of course im gonna load it on the bench (using my own designed "finger meter" ) in order to make sure.

Team pilot for Radix, Helidirect, Logictech, ThunderPower, Fromeco, Gaui
www.liorzahavi.com
03-11-2005 Over year old.
HOMEPAGE  
 
 
kirk
Veteran
Location: Thornton, Colorado

I3DM

"actually, the loads on an eCCPM system are not as hard as on mCCPM"

Load wise on the servo you are correct but from a current standpoint I think the power bus of the RX would see a greater load and more current draw with a ECCPM setup per given cyclic or collective command (you have 3 servos moving not 1 or 2)... I am sure someone on this board can do the math, I unfortually have seen it tested in the air

Good luck dude!!!

Kirk
03-11-2005 Over year old.
 
 
z11355
rrMaster
Location: 10000 is enough time wasted.

I love that in pursuit of the latest 'must have' megapower servo/engine/bling,
absolutely ZERO consideration is given to how the change will affect the rest of
the system.

What a shock that using multiple servos that require a small nuclear powerplant
to power them have a problem getting all the power all of them need from some
tiny thin traces on a printed circuit board that was designed for hundreds of
milliamp current draw.
03-11-2005 Over year old.
HOMEPAGE  
 
 
TMoore
rrProfessor
Location: Cookeville, TN

Lior,

It's amazing what a lowly nicad battery can do in the face of this new lithium ion technology.

Since you seem to have a handle on the power issue. Please read the following in case you have other issues.

If you are running CCPM and need specific software functions to address interaction issues, which you shouldn't really have and don't want to pony up the coin for the 14MZ, the Stylus has had these functions for a while now.


Your Stylus has the following:

CP3-Delay controls the feel of the fore/aft to match the roll cyclic feel.
CP-Linear adjusts for off center servo arms at swashplate extremes.
CP-EPA allows endpoint adjustment for all CCPM Servos.
CPS-Delay allows you to match the servo speed to the slowest servo in the system eliminating swashplate dance.
Servo Limit sets maximum servo deflection no matter what mixing program is invoked that could possibly overdrive the servo in question.

BTW, the Stylus still works pretty good for regular collective machines too, as you know.

All these software options are detailed in the manual that I emailed you last year. It's just a friendly reminder to you of some of those ultra neat functions that won't cost you an arm and a leg to enjoy.

TM
03-11-2005 Over year old.
HOMEPAGE  
 
 
I3DM
rrProfessor
Location: Israel

TM,
Thanks for the reminder, the Stylus is obviously a top of the line radio, and i like it very much !
BTW - any idea how much amp draw can go through the ch B in the Rx ?

Team pilot for Radix, Helidirect, Logictech, ThunderPower, Fromeco, Gaui
www.liorzahavi.com
03-11-2005 Over year old.
HOMEPAGE  
 
 
TMoore
rrProfessor
Location: Cookeville, TN

To my knowledge the current draw is pretty much the same as any other comparable RX out in the marketplace. The biggest thing that will dictate max current draw is the size and length of the wires going to the switch harness, the switch itself, the servo leads and the battery leads. This is the real limiter, IMHO. The servo junction block is a pass through on the RX board and as I said in an earlier post the B-Failsafe voltage is 3.6 volts. The servo pins that are soldered to the board are gold plated and fairly beefy. The wire sizes used in RC avionics were never designed for the current demands that we are placing on them. Do the calculations and you will see how close to the edge you really are.

This is one reason that I use digitals sparingly.

TM
03-11-2005 Over year old.
HOMEPAGE  
 
 
I3DM
rrProfessor
Location: Israel

Just talked to ATX support too (Jack) - he says the shut off voltage of the Rx is 4.4V and apperantly he agrees that the regulator seems to be the problem too - what do you think Terry ? you think the 2 regulators is a good idea ? (and ya i know im stuborn, im really after getting this to work).

Team pilot for Radix, Helidirect, Logictech, ThunderPower, Fromeco, Gaui
www.liorzahavi.com
03-11-2005 Over year old.
HOMEPAGE  
 
 
hhart
Senior Heliman
Location: San Jose, CA

I3DM,

If you are afraid of rx limiting the current output to servo, why don't you just run seperate power bus to ccpm servos and using only signal tapping of rx. this way, power is not suck down from receiver, but instead from new power bussing.

You have to be carefull however, voltage that goes to servo and signal that connected to rx has to be of the same magnitude, other wise, logic gate would not shuts off completely and causing servo to burn excessive power even during idle.

hhart
03-11-2005 Over year old.
 
 
TMoore
rrProfessor
Location: Cookeville, TN

Lior,

I don't see why 2 regulators won't work, but you have to have the battery capacity too.

TM
03-11-2005 Over year old.
HOMEPAGE  
 
 
I3DM
rrProfessor
Location: Israel

hhart, i thought of that too, but that requires a serious modification to connections.

does anyone see a reason why the twin regulators in parallel wouldnt work well ?

Team pilot for Radix, Helidirect, Logictech, ThunderPower, Fromeco, Gaui
www.liorzahavi.com
03-11-2005 Over year old.
HOMEPAGE  
 
 
TMoore
rrProfessor
Location: Cookeville, TN

Lior,

It used to be on the Infinity PCM's that the Battery Failsafe was set to 3.6 volts. Per the Stylus manual the B-Failsafe is set to 4.7 volts if that function is activated in the TX.

Do you have B-Failsafe activated in the TX?

TM
03-11-2005 Over year old.
HOMEPAGE  
 
 
I3DM
rrProfessor
Location: Israel

Yes it is active.

right now i have the entire twin regulator system installed on the machine with 2 switches, so that i can check easily with either one of the regs or both (just flipping switches).

im just waiting for some heatshrink tubing tommorow, so that i could recover the Duralite pack after installing lead #2 and i can start thinking of test flying the machine.

Team pilot for Radix, Helidirect, Logictech, ThunderPower, Fromeco, Gaui
www.liorzahavi.com
03-11-2005 Over year old.
HOMEPAGE  
 
 
TMoore
rrProfessor
Location: Cookeville, TN

Disable B-Failsafe and rerun the tests.

TM
03-11-2005 Over year old.
HOMEPAGE  
 
 
I3DM
rrProfessor
Location: Israel

just did - exactly the same, on either of the regs (alone) it freezes with the LED meter going down about half way, and as soon as i turn both switches on - walla, everything is perfect with the LED meter staying on the top green light no matter what i do.

Team pilot for Radix, Helidirect, Logictech, ThunderPower, Fromeco, Gaui
www.liorzahavi.com
03-11-2005 Over year old.
HOMEPAGE  
 
 
TMoore
rrProfessor
Location: Cookeville, TN

Good, it seems that you have solved the problem. Maybe it wasn't enough regulator capacity.

TM
03-11-2005 Over year old.
HOMEPAGE  
 
 
I3DM
rrProfessor
Location: Israel

Thats what i would say, im starting to feel confident in this system since it is very obvious that as soon as #2 regulator goes on, the system performs flawlessly.

Team pilot for Radix, Helidirect, Logictech, ThunderPower, Fromeco, Gaui
www.liorzahavi.com
03-11-2005 Over year old.
HOMEPAGE  
 
 
ShuttleSmasher
Senior Heliman
Location: Owner of TheModelWorx.co.uk

i3dm, you should use the fromeco Super Regulated Reliaswitch, its perfect for the job, 9=10 amps cont, and 30 amp peek.

take a look...
http://www.fromeco.org/Shop/aSuper Reliaswitches.htm

we use them on our dyna-x's with ko pro po servo's

Gary

Team Dyna-X
03-11-2005 Over year old.
HOMEPAGE  
 
 
hhart
Senior Heliman
Location: San Jose, CA

I3DM,

Another way that you could do is to install big fat capacitor in the power bus for each cyclic servo. Maybe inorder of uFarad. This way, when cyclic uses peak current, local to servo power bus, this extra capacitor could supply current back. In another sense, it would stabilize power bus local to servo.

Another concerns is, would this shift regulator phase margin? if the control loop poles shifted to negative side, you are screwed. regulator would oscilates.

hhart
03-11-2005 Over year old.
 
 
I3DM
rrProfessor
Location: Israel

Just got off the phone with Jack from Duralite, he says i should use 2 regulators also, so i guess i was on the right track !

Team pilot for Radix, Helidirect, Logictech, ThunderPower, Fromeco, Gaui
www.liorzahavi.com
03-11-2005 Over year old.
HOMEPAGE  
 
 
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Radio - Servo - Gyro - Gov - Batt > Problem using 94758Z servos on eCCPM - NEW FINDINGS!
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