Cycle Analyst diagram for Magic Pie. Speed and current control.

[Leslie]

I did some research around some important interaction between Alan and Gary Salo regarding the CA-SA.

Alan managed to suggest the speed control fix for the magic controllers and Gary has tried and tested this since with good results.



The above diagram is a summery of the conclusion of the said discussion.  The thread is beginning to be buried since so I thought I would refresh and condense the information in its own subject heading.

Can we get a sticky for this subject so it doesn't get buried again.  And I will do some work to get the Stand alone version working like the DP versions too so we can mod the CA to not need the magnet sensors off the spokes.

[GM Canada]

One thing that is unclear to the non electrical person is the diode. In a wiring diagram it shows an arrow for direction of current. But on the diode itself it only shows a line on one end. I guess the arrow points to the line? I can recal how I did mine, it just works so I must have got it right but I do recall this was a little confusing to a rookie like myself.

Gary

[Bikemad]

One thing that is unclear to the non electrical person is the diode. In a wiring diagram it shows an arrow for direction of current. But on the diode itself it only shows a line on one end. I guess the arrow points to the line?

This should help to clarify it:



Alan
 

[Leslie]

On a normal rectifier or switching diode the line means block current and on schematics it means block current and the arrow means current to pass this direct6ion.

On zener diodes this is the same thing but the zener has a breakdown voltage that allows current to pass the block line at a set zener voltage.

             Resistor   6v zener
GND------WW------>Z---- +12
             ^6V+^            <<< current.

The voltage past this zener drops by the zener voltage, so between the arrow side of the diode and negative it will read 6v drop over the resistor.

They work like a simple regulator in some configurations.     So this zener diode works opposite to the way normal diode work and a lot of apps it is faced the opposite with the arrow facing the opposite direction to the current..

You got the diode right as this picture comes from the CA website.



As you can see the diode points to th pad.

No signal is sent to the motor controller via the th pad, nothing can get past that diode from the CA so its just a variable shunt controlled by the speed data comming in from the tacho..

In most setups, the user typically has a throttle signal that varies from close to 0 or 1V when it is off, up to 4-5 V when the throttle is fully engaged. For proper operation of the Cycle Analyst limitting features, the signal for the motor controller should be the lower of these two voltages. An easy way to achieve this without even opening the controller is with a diode and current limiting resistor on the throttle line as shown in the following schematic:

The explaination to this is terrible, what two voltages.  The lower of the two voltages 4v and 5v or does he mean 4v and 0v outright.  What?

the output line was modified to include a 1k resistor (R6) to protect the silicone. This however means that the Over-Ride line can only source or sink small currents, and if more than a mA needs to be drawn from the output, then resistor R6 should either be reduced in value to a couple hundred ohms, or possibly shorted out entirely.

Man this needs to be rewritten.  Outputs to what, from where?    My handle on this means the throttle output.  But now we need to supply more than ma to where?  The sink or the controller.  Again I suggest it cant sink more than a ma through r6, so it means that the output of the throttle may need less resistance  to sink more current away from the controller throttle input.



Not very well explained at all.

R6 is our holy grail IMO.

States that voltages under 4v need not the resistor or the diode.  Maybe the resistor will pass but the diode is there to drop the 5v output to 4.2v and resistor to 4v.  The work need to be focussed more on the r6 resistor.



In this case you need no diode or resistor as the GM throttle outputs to 3.8v and any resistance to the TH pad should return incorrect values with the diode..

It works by the way of when the speed hits the set point the th pad can sink the current from the the throttle output in to an op amp that can shunt any current from the throttle signal to the contoller until speed limiting is achieved.


What needs to be known is the amount of current that comes from the throttle to the controller and how much needs to be sunk into the CA for this to work.

The voltages are all well and fine but if the sink is too much, the voltage setting will mean nothing and die when the throttle overide kicks in and sinks the volts way below the ITermMin and slow the bike to a stop instead of limiting it.

Or if the sink is not enough then then speed limiting will be uneffective.  The advanced settings can allow some room to play by over or under stating intermmin but the importance is to get the sink close enough to use this feature reliably and to its full potential.


I just may have to get my amp meter out again and sort this out properly.

[DirtyGinge]

I think one of the basic problems with the CA is that the whole manual and guides on the web are written with the whole idea that someone is fully versed in electronics before they start......What is really needed is for an idiots guide, for the likes of myself, who , know basic electronics, but only start to modify after 5-6 pints of lager....

My two cents for the newbies who may visit the thread

What the Cycle analyst want to do is steal the voltage that was meant for the Magic Pie, so the Magic Pie gets nothing or little.....it does that by opposing the throttle signal, so if the throttle is 3v, the cycle analyst for example can set the voltage of the TH pad to 2 volt, and the electricity will happily go there instead of the controller.........bit like, if you get offered a pint, your wallet finds the pocket far more confortable than your hand .....

A resistors job is exactly that, to resist the flow of electricity, a bit like a doorman in a nightclub...and by OHM they mean how much is stopped ( i.e. how big the doorman is ), different values let more or less through

Jumper R6 on the circuitboard of the cycle analyst stops a lot of voltage going back into the cycle analyst, but the Magic pie produces more than the resistor can handle, and this means that the resistor needs to be "bypassed" in order to let the current through....in my case a metal pin soldered to both ends, now looking like a u shape.....

so to summarise quickly....
the Resistor 330 OHM stops the throttle sending too much current, so the cycle analyst can steal whats left
the Diode makes sure that the current only goes one way ( so when you turn on your cycle analyst, your bike's front wheel doesnt go cruising through your crotch ( long story, with a multimeter accident)
the R6 jumper needs to be bypassed so that the signal from the throttle can be over-ridden

after that, its just tweaking in the settings

good luck all

any help I can give, please email me paulkinsella@hotmail.com..... ...ill try to help if I can

[GM Canada]

Hi Paul

What a wonderful style of writing you have. Everything is easily understood and I had a few laughs along the way. Thank you for that!

Gary

[Leslie]

The th pad is a current sink and nothing more.  If it was voltage based as in resistive energy control by reference voltage controll we wouldnt have to play around like we do with R6 and diodes and what not..

Its prurely based on the current that comes from your throttle and is required by your controller.  The volt settings are a hit miss thing very losely implemeted on basic charasteristics most controllers throttle interface exhibit.  

The rest is getting your hands dirty and actually measuring the current that goes to your controller when you twist the throttle and sinking the correct ratio of current to the th and controller to achieved the voltage set by interm.

Its not rocket science and to s small degree, nothing to do with how much you know about electronics.  Even an expert would have problems following that write up as it does not define exactly what part and piece they are talking about.  Even an expert would to fill in the gaps to have i9t make sense.

I think it more like its written by someone who knows what bits theyre thinking of in their own head.

Other than that I suspect the diode and resistor do not belong there and looking closer at the mod it is not correct..  You may get it to work but the TH pad would be lucky to get 2.83v to sink not 4v as the manual states..

[Leslie]

In most setups, the user typically has a throttle signal that varies from close to 0 or 1V when it is off, up to 4-5 V when the throttle is fully engaged. For proper operation of the Cycle Analyst limitting features, the signal for the motor controller should be the lower of these two voltages. An easy way to achieve this without even opening the controller is with a diode and current limiting resistor on the throttle line as shown in the following schematic:

In laymen terms to read this means one does not need the diode and or resistor if you have the lower of these two voltages.  One need the diode and resistor to achieve 4v to the th pad.  As we all know the MC outputs lower than 4v.  And the voltage from the resistor and diode would take the voltage down below I repeat below 3v.

Either the web site is wrong or poorly written or you guys are right.  Either way the Mod here contradicts what is written on the Web site when it concerns the magic controller.

Jumper R6 on the circuitboard of the cycle analyst stops a lot of voltage going back into the cycle analyst, but the Magic pie produces more than the resistor can handle, and this means that the resistor needs to be "bypassed" in order to let the current through....in my case a metal pin soldered to both ends, now looking like a u shape.....

Like reducing ohms in a circuit adds more protection to the "op amp" that the R6 resistor protects?  The resistor is there to protect the op amp from higher voltages.  And reducing this resistor only puts the op amp in danger not "the MP produces too much for the resistor" (you mean op amp) yep, so we need to put the op amp in more harms way, is exactly what you are saying in this quote.  Not!

Justin means exackerly this.

If someone hooks an undermined power source to the th pad it will fry the op amp protected by R6.  If the current demand is too low from the controller off the throttle, the th pad R6 resistor needs to be shorted to lower the resistance for sinking more current off the throttle to the TH pad to make the throttle limiter effective.  The hall sensor is literally loaded higher in limit mode and current paths are split to the controller and to the th pad.  This creates a voltage drop straight over the hall sensor and 330 ohm resistor.  where there is a voltage drop you have a current impedance. in turn the current that is shunted to the th pad limits the current going to the controller.  So in essence it not voltage based its current based.

I can feed a control throttle signal to a controller 10v @.005ma and the bike it would not move a single inch.  Or I could feed the controller 4v @ 100 amps and the controller would still only draw 5ma or so from the throttle.

Its not all cut and dry.

As far as the th pad sending volts out to the controller past the .8v that the throttle gnd should slam down, with out a 330 ohm resistor the th pad volts should be slapped down easily by the hall sensors path to ground @ 0 twist..

So omitting both resistor and diode in the mod diagram should have any current from the th pad sink into the gnd at the hall sensor no problems.

So diode needing to block th op amp transients or non load voltage tails I have no clue what you talking about. Unless you were to hook up the CA to the controller first with no throttle connected.  You could have problems then.

As it states you need the diode and resistor for voltages @ 5v so the CA does not sink too much current from the throttle.

But hey I could be wrong.  I just switch my CA on and it went up in smoke and I had to switch it off to avoid a fire..  Installed and untouched since.

[DirtyGinge]

Hi

Yes I agree there is a lot more to it, and yep, shorting R6 to allow currents back into the op-amp is certainly a massive risk, especially if someone wires it wrong......

However, as this was the reason that I purchased the CA, to make the motor"legal", I had to try, and the guides written out there are somewhat cumbersome......I didnt find any basic information from anyone apart from gary on the mod that works with the Magic Pie, tried the other method, didnt like it

The average person on the street will have no idea what a voltage sink is ( toaster in the wash basin ?) or the concept of what its trying to do, so I wrote my guide to try and help them more understand the concept, then the other forum posts would begin to make sense...

I agree also that the Th pad will not sink the 4V, more like 2.5, but this is perfect in limiting the speed, expecially once my fat A$% is on the saddle.....
Shame the manufacturers cant make it a little easier for the newb

[Leslie]

Hi

Yes I agree there is a lot more to it, and yep, shorting R6 to allow currents back into the op-amp is certainly a massive risk, especially if someone wires it wrong......

However, as this was the reason that I purchased the CA, to make the motor"legal", I had to try, and the guides written out there are somewhat cumbersome......I didnt find any basic information from anyone apart from gary on the mod that works with the Magic Pie, tried the other method, didnt like it

The average person on the street will have no idea what a voltage sink is ( toaster in the wash basin ?) or the concept of what its trying to do, so I wrote my guide to try and help them more understand the concept, then the other forum posts would begin to make sense...

I agree also that the Th pad will not sink the 4V, more like 2.5, but this is perfect in limiting the speed, expecially once my fat A$% is on the saddle.....
Shame the manufacturers cant make it a little easier for the newb

Agreed,

It would help a little if the power from and to the said devices were refereed to in every instance in the write up.

Its very hard to communicate such information when the author knows the circuit well and has to communicate on a lower level or even to a person who is a little more tuned to the jargon may still get confused if details around the circuit are a little lose..

Reading it a few times helps and the dots start to join.   

[wattsup]

ok, for someone with limited knowledge of the mysterys of things leccy, what does this do, cut power to motor. for a rider in uk, a flick of a switch would be great to limit to legal outputs. would this work with external controller. i,ve seen something like this for ca but cant seem to find it again.

[motor_magic]

Has anyone got this working for the MP3?