General Category > eBike Mods/Legalization
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:
--- Quote from: GM Canada on November 13, 2010, 11:44:02 AM ---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?
--- End quote ---
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..
--- Quote ---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:
--- End quote ---
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?
--- Quote ---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.
--- End quote ---
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
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