I Think the drawing Bikemad put up is a good enough solution. The cycle analyst is better though. (But expensive) I am not sure yet How exactly I am going to do this but I will also put this in the dutch forum.
www.naafmotor.nl (in Dutch)
Maybe you can look into the option Bikemad gave and also post this in the dutch forum for dutch readers to find solutions online as well..
You could also buy a cycle analyst of cource.
So The way I am going to use the cycle analyst to is like explained below.
Got this from the cycle analyst home page.
Throttle Over-Ride DetailsIn order to take advantage of the speed limit, current limit, and low voltage cutout, the Cycle Analyst needs to be wired in such a way that the Throttle Over-Ride output is able to take charge of the motor controller when one of the limits is surpassed. This is already accomplished in our CA-DP and DPS models when connected to any motor controllers which have the 6-pin Cycle Analyst connector, so no additional wiring is required beyond plugging the two devices together. If you are connecting it to a 3rd party controller then it will be useful to understand the following details.
The over-ride output is an analog voltage that can range from 5V down to 0V. When it detects that a limit is exceeded, the voltage begins to ramp down from its resting point (set by ItermMax), until power to the motor is reduced and the limit (speed, current, or voltage) is no longer exceeded.
The actual output is derived from an op-amp on the circuit board, and it is capable of both sinking and sourcing current. In the original Cycle Analyst boards (identified by a lack of label on the PCB) this output was wired directly from the op-amp, so it was quite stiff, but also made the board vulnerable to damage if the Throttle Over-Ride was accidentally wired incorrectly to a voltage source. In PCB revision 7 (labelled DB2 Rev7b), 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.
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 is with a diode and current limiting resistor on the throttle line as shown in the following schematic:
In cases where the controller circuitboard is readily accessible, then you will often find that there is a series resistor already on the PCB and the throttle over-ride should ideally tap in just after this point, and then an additional resistor is not required.
With the Stand Alone and High Current versions, you will need to drill a hole through the enclosure and feed a wire to the Th pad on the CA circuit in order to access the over-ride signal.
The response time and stability of the limiting features can be adjusted by changing the gain values in the advanced setup menu. Each one is implemented as a Proportional / Integral (PI) controller. Gain settings that are too high will lead to oscillations about the set point, while gain settings that are too low may cause large overshoots and time lags before the values have stabilized.