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Multiplex 4000 More Programming Questions

Old 06-07-2003, 08:24 PM
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jtholley03
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Default Multiplex 4000 More Programming Questions

How do I reverse the just the trim?

Rudder servo - I have arm on Futaba 9001 servo as close to mechanical center as possible. I have to dial in 10 in center to physially center it. Control maxed at 100% and travel 109 each way. When I run the trim center to ten I'm losing throw on the right throw. Anyway to get this back? I have my mechanical throws maxed.

Thx
Old 06-07-2003, 08:46 PM
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HarryC
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Default Multiplex 4000 More Programming Questions

To alter centre whilst moving the travel end points along with the centre, use the servo centre, not the control centre trim. Put the control centre trim back to zero. Go to menu 1, servo, Centre+lim, adjust the centre value to probably +10%. Servos go to true centre and stay there while this parameter is activated so you can't adjust it "live", have to make an adjustment, come out of the centre parameter say by pressing top right triangle button and see where the servo goes to.

There is another hint in your explanation. You say travel is maxed at 109%, I take it you mean servo travel. If your LIMIT is still set at the default 100% then your servos are stopping at 100% and are not travelling that last bit of stick movement. Move the stick slowly and watch the servo carefully, you will see the servo stops moving before you get to the end of stick movement - the last ~1/10th of stick movement is wasted. Menu 1, servo, centre+lim, alter limit value to 109 in both directions.

BTW, be careful about asking to reverse the trim! You can actually do this, have the trims working the opposite direction to the controls which makes a whole puzzling mess of trying to trim the plane in flight!

Harry
Old 06-07-2003, 09:00 PM
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Default Harry to the rescue

Thx I should know that by now.

But seriously I DO need to reverse my trims.

My controls work correct but my trim is backwards on the Rudder and Aileron since I have them reversed. Was a fun day of flying trying to trim in reverse.

Now if the damn rain would stop I can go tear it up again.
Old 06-07-2003, 09:21 PM
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HarryC
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Default Multiplex 4000 More Programming Questions

Ah, you made the deadly "error" of reversing a control instead of reversing the servos! Not a major problem as long as you remember to reverse the trims too, as you found out! I bet that flight was fun. I have my own rule of never ever never reverse the controls, I always set direction at the servo level. There's no reason not to reverse the controls as long as you know all the effects it has and consequently the rules to be followed to ensure that there are no unexpected effects. I find it just easier to leave it alone and work at the servo level.

To reverse the trim menu 1, controls, TRIM TRAV, select the number value with bottom right triangle button and press R. The number will go from + to -, or - to + and that reverses the trim effect.

H
Old 06-07-2003, 11:05 PM
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Default I knew you would tell me I F'd up

Ok, I learned wrong. Determined to do it correct, tell me how to properly reverse the servos. I get it but miss the obvious (if you can't tell).

Thx for the help.

PS the heli goin down is from a Futaba receiver not from pulling up.

Not an "ID 10 T" error (IDIOT) as it would appear.
Old 06-08-2003, 07:46 AM
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HarryC
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Default Multiplex 4000 More Programming Questions

You can carry on using control reversing if you want as long as you work through all the effects it has downstream of the control. A control is at the top of the stream so everything is downstream of it and will be affected. But if you miss one of them, you get the sort of problem you ran up against and it's guaranteed that you won't notice it until you are in flight.

Since the servo is at the end of the stream there is no further downstream to affect, so altering direction at the servo has no other effects and therefore I feel safer doing that. Thanks to Multiplex software, each input at the servo is independently set for its direction, rather than just some sort of global direction for that servo. So for example if aileron and flap and spoiler are input to your ailerons, each one of those inputs can be reversed without having any effect on the direction of the other inputs into the servo. Go to menu 1, servo, travel/curve, choose the input (there is no choice if servo is assigned direct to a single control rather than to servomix), activate the travel value by pressing bottom right triangle button, then press R to reverse the direction. You will see the graph swap its slope around as you do it.

The reason that the trims don't reverse with the controls is that trims are actually proper independent controls in their own right just like the two big sliders E and F, they are not simply slave pots wired into the control stick. The full range of assignable controls is not just A to M, at the end of the assign controls menu you will find TA to TD waiting to be assigned to a function. Like all controls they are not automatically assigned to a function, however they do default to being mixed into the stick next to them at 30%. It's the only time in the Profi radios that mixing takes place at the control level instead of the at the servo level. That is why if you reverse the control you get the problem. Reversing the control reverses the stick effect, but the trim is an independent control being mixed in a particular direction and it will continue to mix in that direction until you go into its mixing software and reverse it. The trim's mixing software is menu 1, controls, TRIM TRAV. The value shown is the mixing rate and the +/- shows the direction of mix. I find the default mix 30% a bit coarse so my master model is set to 20% except for throttle.

This method allows the trims to be used as separate controls. Someone on RCU once said he wanted a servo to control a proper elevator trim tab using its own channel, but working off the elevator trim lever which in turn would have no effect upon the elevator servo, could any radio do it? Of course the reply was the Mpx 4000 can. Set TRIM TRAV to zero% so it does not affect the ele servo, then go through the standard process to assign a control and servo. Assign the relevant T for your mode to Aux 1 function and assign the trim tab servo to aux 1. For some other application, leave TRIM TRAV at normal value so it works on the main servo, aux 1 and its servo could be used for something utterly different to the main control with its own travel curve. Or rudder trim could be assigned to aux 1 but no servo assigned, and aux 1 mixed to the servos for twin throttles so that rudder trim impacts the separate throttle values. The creation of trims as independent assignable controls allows for all sort of possibilities for the creative and adventurous.

Harry
Old 06-08-2003, 01:37 PM
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Default Awesome

OK TA-TD now I know what they are.

Is there anyway to force MORE travel out of a given servo?

Thx for the awesome info.
Old 06-08-2003, 06:04 PM
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HarryC
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Default Multiplex 4000 More Programming Questions

To get max servo travel you need the control travel to be at 100%, servo travel to 109% and servo limit to 109%.

Multiplex 109% travel equals a JR Tx at its max allowable travel of 150% and a Futaba at its max allowable travel of 140%. At those percentages all three of those brands are generating a servo signal of 0.9ms or 2.1ms. There is physically no more travel available.

Harry
Old 06-08-2003, 08:16 PM
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jtholley03
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Default Ok I have that - Switch ?

Have a pull pull on rudder that I was just trying to get an extra 1/4" on each side but guess not. I have it maxed out both mechanically and electronically.

I have 2 3-way switches. #1 and #12. I have my flaps assigned to the #12 switch to act as ailerons. Middle of switch is off. How can I use the 3rd position. I only get one switch choice for 12. I would like the other throw to be flaps coupled to elevator instead of having that on switch one. While we're at it I would like to throw 15% expo in when I switch the flaps to ailerons.

As always you are a wealth of knowledge. Can't wait until I know this thing inside out.
Old 06-08-2003, 08:52 PM
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HarryC
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Default Multiplex 4000 More Programming Questions

Other brands of radio can hard-code into the processor whether a switch is 2 or 3 position since the radio comes like that and you can't change it. Multiplex expects you to fit what you want so it can't hard code an input as being a 2 or 3 position switch, therefore you have to select it in software. This applies only to secondary switch inputs S01-S12, a control input G-M expects a proportional input so they interpret 3 position switches correctly.

To tell the radio that a switch S01 - S12 is a 3position switch, assign a Transfer switch to it. Transfer switch is the 3 position software interpretation. Then when you want to assign parameters like mixing or expo to that switch you assign them the T switch, not the S switch. You can still assign things to the S switch which behaves as a 2 state switch while at the same time assigning things to its 3 state T switch!

Menu 2, switches, scroll to Transfer sw: T1
then choose From switch S12

Now assign mixers, expo etc to T1 and not to S01 or S12. Assign switch in the normal way, keep scrolling up through the list and you will find T1 comes immediately after S12. However there is a crucial difference between assigning an S or T switch. You just get one menu option for each S switch and toggle its on/off state using R. With T switch keep scrolling and you will see there is T1-1, T1-2, and T1-3. These correspond to the 3 possible switch positions, T1-3 is switch up and T1-1 is switch down T1-2 is middle. You assign the position that you want. Lets say you want switch up (T1-3) to be the ele->flap mix. Go to menu1, servos, flap servo, ele input , make sure that you put the switch to the up position and then set switch to be T1-3*. If the asterisk is not there with the switch physically in the correct position, press R to bring it on. If the * is on in one position it is off in both other positions. If you leave the * off in one position it is on in both other positions, useful when you want something off in one position, flight mode etc.

If you want switch down to be the mixer, then set the switch to be T1-1*

Go to expo and set switch to T1-X* where X is the position you use to switch the aileron on. You may wish to reset the aileron input in the flap servo to T1-X rather than to S12.

Harry
Old 06-08-2003, 09:16 PM
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jtholley03
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Default Thx

NT

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