RoboteQ AX2850 user manual Powering the Controller Using a Main and Backup Battery

Controller Powering Schemes

There is no need to insert a separate switch on Power cables, although for safety reasons, it is highly recommended that a way of quickly disconnecting the Motor Power be provided in the case of loss of control and all of the AX2550 safety features fail to activate.

The two red wires are connected to each other inside the controller. The same is true for the black wires. You should wire each pair together as shown in the diagram above.

The yellow Power Control wire and the thin black wire MUST be connected to Ground to turn the Controller Off. When the controller is Off, the output transistors are in the Off posi- tion and no power is drawn on VMot.

For turning the controller On, even though the Power Control may be left floating, when- ever possible pull it to an unfused12V or higher voltage to keep the controller logic solidly On. In applications where the motors could be made to run through external force (electric vehicle going downhill, for example), and generate 40V or more, a diode should be placed across the fuse & emergency switch to provide a path, under all circumstances, for the regeneration current. See “Power Regeneration Considerations” on page 37.

Important Warning

Do not rely on cutting power to the controller for it to turn off if the Power Control is left floating. If motors are spinning because the robot is pushed are pushed or because of inertia, they will act as generators and will turn the controller On, possi- bly in an unsafe state. ALWAYS ground the Power Control wire to turn the controller Off and keep it Off.

Important Warning

On versions of the AX2550 with PCB revision number lower than 5.2, the backup power supply applied on the Power Control wire must NEVER EXCEED 13V. Perma- nent damage may otherwise occur. The PCB revision number can be found on the sticker on the case’s bottom.

Important Warning

Always connect the thick black wires to ground BEFORE connecting the red wires to the battery. If the motors are activated while the connection to ground is done solely via the thin black wire (or the ground wire in the RS232 cable), the ground wire will

overheat and/or melt .

Powering the Controller Using a Main and Backup Battery

In typical applications, the main motor batteries will get eventually weaker and the voltage will drop below the level needed for the internal microcomputer to properly operate. For all professional applications it is therefore recommended to add a separate 12V (to 40V) power supply to ensure proper powering of the controller under any conditions. This dual battery configuration is highly recommended in 12V systems.

AX2550 Motor Controller User’s Manual 33