Data Sheet

4 MDC22xx Motor Controller Datasheet Version 1.2. January 18, 2014

Emergency Switch or Contactor

The battery must be connected in permanence to the controller’s VMot power via an input emergency switch or

contactor SW2 as additional safety measure. The user must be able to deactivate the switch or contactor at any

time, independently of the controller state.

Precautions and Optional Connections

Note 1: Backup battery to ensure motor operation with weak or discharged batteries, connect a second battery to

the Power Control wire/terminal via the SW1 switch.

Note 2: Use precharge 1K, 0.5W Resistor to prevent switch arcing.

Note 3: Insert a high-current diode to ensure a return path to the battery during regeneration in case the fuse is

blown.

Note 4: Optionally ground the VMot tabs when the controller is Off if there is any concern that the motors could

be made to spin and generate voltage in excess of 30V (MDC2230), 50V (MDC2250) or 60V (MDC2460).

Note 5: Beware not to create a path from the ground pins on the I/O connector and the battery minus terminal.

Use of Safety Contactor for Critical Applications

An external safety contactor must be used in any application where damage to property or injury to person can

occur because of uncontrolled motor operation resulting from failure in the controller’s power output stage.

The contactor coil must be connected to a digital output configured to activate when “No MOSFET Failure”. The

controller will automatically deactivate the coil if the output is expected to be off and battery current of 1A or

more is measured for more than 0.5s. This circuit will not protect against other sources of failure such as those

described in the “Important Safety Disclaimer” on page 3.

PwrCtrl

SW1 Main

On/Off Switch 1A

Diode

>20A

Resistor

1K, 0.5W

I/O Connector

VMot

to +40V Max

Digital Out

Ground

Main

Battery

FIGURE 9. Contactor wiring diagram