accessories
Power Accessories
VEX Power Expander,
continued
VEX Power Expander •
2
Usage
• Connect a secondary 7.2V battery to the power connector of the Power Expander. The Power
Expander LED should flash green briefly signaling power is being supplied to it.
• Connect up to four (4) Microcontroller Motor Ports to the “In” ports of the Power Expander
using VEX PWM Cables.
•Connect VEX Continuous Rotation Motors or VEX Servos to the corresponding “Out” ports of
the Power Expander.
• Slide the Power Expander PWM Lock to secure cables.
• Turn on your Microcontroller. The feedback LED should now show the status of the Power
Expander and motors/servos should respond normally based on the secondary battery power.
Note: When using Non-Keyed PWM Cables on the VEX Power Expander, the Gnd/Blk wire
should be closest to the key slot on the STATUS and IN Ports, and it should be the furthest
from the key slot on the OUT ports.
Status Port
The VEX Power Expander includes a Status port that can be connected to an Analog/Digital
input on the VEX Microcontroller. The VEX Microcontroller can use this data to calculate the
approximate voltage of the battery connected to the Power Expander. To determine this value,
divide the Power Expander read-out by 70.8.
Example:
The VEX Power Expander returns a value of 531.
531 / 70.8 = 7.5
7.5V is the current voltage of your Power Expander battery.
If the battery drops below 339, the internal Circuit Breaker may have tripped. Set the joysticks
to neutral for 5 seconds to let the Circuit breaker reset.
LED Feedback
The VEX Power Expander also incorporates an internal circuit breaker to prevent damage to
the unit or connected devices. Refer to the following LED status chart for more information.
The Feedback LED provides the battery and circuit breaker status of the unit.
Green
Battery Good
Yellow
Battery Low
Red
Battery Critical
Slow Red Blink
Circuit breaker is tripped
Fast Green Blink
Circuit breaker was tripped / Battery Good
Fast Yellow Blink
Circuit breaker was tripped / Battery Low - Charge soon
Fast Red Blink
Circuit breaker was tripped / Battery Critical - Charge Now
