2015:Electrical Main
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IO Interface Map
Sensors
Drive Base:
- two encoders (left and right)
- two channels for each encoder
- gyro and accelerometer compound board (am-2067, containing ADXL245 & ADW22307)
- Need to use strafing in autonomous!
- 2-speed shifter (pneumatic)
Lifter:
- flag sensor at bottom/home for calibration
- flag sensor at highest extent
- 63R256 encoder for interpolation between top/bottom
- do we need hard stops?
- lifter needs to be physically removed
- 2 RS775-18 motors
- 1 Camera (Stationary)
- bike brake with pneumatic actuation (double acting cylinder, single solenoid)
Gripper:
- 63R256 encoder after gearbox output
- flag sensor for inner home position
- the motor is a RS550
- 2 (or 1?) banner sensors out on grippers for tote acquisition (previously ultrasonic distance sensor)
- Flag (?) sensor for wide tote config
Stabilizer:
- pneumatic on/off (single solenoid, dual acting cylinder)
Interface Circuits
Banner Photodetector Sensors:
- Q10 Series (Q10AN6R Detector)
- Sensor is NPN open-collector output
- Sensor off-state leakage is 10uA max.
- Sensor on-state logic low is 0.5V max @ 10mA max
- RoboRIO DIO [0..9]
- Have internal 40K pullup resistors to +3.3Vdc
- RoboRIO DIO VIL=0.8V max
- RoboRIO DIO VIH=2.0V min.
- Interface Circuit
- Sensor off-state leakage of 10uA through RoboRIO pullup of 40K drops 0.4V, so logic high is 3.3V - 0.4V = 2.9V
- Logic high is safely above RoboRIO VIHmin of 2.0V
- Sensor on-state logic low of 0.5V is safely below RoboRIO VILmax of 0.8V.
- The current that the sensor must sink is (3.3V - 0.5V) / 40Kohms = 70uA, which is well below the max sinking capability of the sensor of 10mA.
- So no external interface circuit is required - the Banner Sensor detector of this type (NPN O.C.) may be wired directly to the RoboRIO DIO.
- If desired, however, a lower resistance pullup could be added to lower the impedance of the interface, which might help reduce susceptibility to electrical interference. (minimum value of pullup approx. 2.7Kohms to still give good margin for logic low condition, with 1mA current sink.)
Robot Indicators
- Lift Position
- LED strips on rear of lift which indicate gripper height position
- "Bar Graph" style display
- Adressable type LED strips so that can be turned on/off individually
- Gripper Open Width
- LED strips on rear of lift at the gripper leadscrew
- "Bar Graph" style display from the center
- Addressable type LED strips so that can be turned on/off individually
- When gripper Banner sensor is tripped (tote within grippers), LEDS change color
- LED Strip driver requirements
- 30LED/m strip is 2A/m (9.5W)
- 60LED/m strip is 3.6A/m (18W) - preferred for high resolution "bar graph" display
- Estimated total LED strip length for robot is 3m
- Total 5Vdc current requirement for 60LED/m is 10.8A for 3m (if 80% efficient 12V/5V converter, 12V current would be 13.5A)
Component Specifications
File:RoboRIOspecifications.pdf
File:2013 Motor Data Table.xls
Electrical Indicators Reference Link
