[Jaine Perotti]

I already PMed you Anton, but I will post this so that others who are asking similar questions might understand.

No, you can not limit the output of a spike. The spikes are relay switches, which can only be programmed to be on/off. You either have the full voltage running through them, or none at all.

Here is a simplified version of what would need to be done:

To do what you want to do, you need to use a speed controller, not a relay. Speed controllers have an analog input/output. In your program, their range of values is 0-254, 0 being full reverse, 127 being neutral, and 254 being full forward.

The way a speed controller works is this: based on these values in your program, the speed controller will give pulses of electricity to the motors at a specific wavelength. For a slower speed, the speed controllers will give pulses at a lower frequency, and for a higher speed the speed controllers will give pulses at a higher frequency.

So using a speed controller, set the output to the values that you desire in your program. Using this method, you can easily set a motor to run at half speed.

Hope this helps,
-- Jaine