+ User Manual
port, HDMI connector and uSD card slot while mounted on the BeBoPr. This feature was
propagated into the design of the +. Extended pin-header connectors create a similar
gap between + and BeagleBone.
Wide input power range
The step down converter has been re-designed to operate from a DC supply voltage in the
range from 12 to 24 Volts. It's still using the same (proven) step down converter as before but
some of the components have changed so that it now can operate at 24 Volts too.
More power for heaters
Since the input supply voltage is also used for the heater outputs, these can now generate
more heat (power) without exceeding the maximum allowed currents. The input power
connector has also been replaced by a type that allows 16A (instead of 12A) of continuous
current. Now it is possible to control a heated build platform and an extruder simultaneously
without exceeding the maximum current specifications.
Single fuse
The expensive and hard to get SMD fuses on the three PWM outputs have been replaced by a
single 5×20 mm fuse. This fuse is now placed into the board's input power line.
Input power LED
A green LED located near the input power connector indicates the presence of supply power.
It will not light if the fuse has blown. This LED replaces the three green LEDs
I2C connector
The BeagleBone's I2C2 bus is now routed to a 4 pin connector, no need to solder wires directly
to the board any more. This allows I/O expansion or connection of a simple I2C LCD. A level
shifter allows connection of 3.3 or 5 Volt powered devices without chance of damaging the
BeagleBone.
Emergency Stop input
The BeBoPr now also has a
hardware
emergency stop (ESTOP) input. Activation of the ESTOP
signal negates the I/O enable without depending on the software. The ESTOP immediately
disables the PWM outputs and stepper signals. A red LED signals the ESTOP state.
If preferred, the ESTOP signal can be configured to latch (remain active once asserted) until
it's cleared by software (negation of the I/O enable signal). Closing a jumper on the BeBoPr
activates the latch.
The ESTOP signal should connect to a normally closed contact or some open collector / open
drain type sensor. When not used, a jumper or piece of wire can replace the sensor. An
external opto coupler / isolator can be used to interface to 24 Volt signals.
version 1.4.9 (09/04/14)
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