Ports and Plugs

The sockets on MV are not the same Left&Right
Re Analogue port Pin Assignment

the manual is correct, but confusing.

The diagram on page 31 shows the pin assignments, but you have to note the shape of the socket holes........the "T" shapes are towards the outer edge of the Motorvator.

Strange Voltages on Action Port
Re Action Outputs

The RIght Hand PIN will not necessarily be +5V. In fact, it will be whatever voltage is on the Action Power Input.

The Left Hand PIN will be either Action Power Input - 0.7V, or Ground (when the Action Port is ON).