FRC Robot Wiring

Baltimore Area Alliance FIRST Robotics

October 26, 2013

What We Will Cover

Basic concepts of electricity and circuits

Each part of the FRC circuit will be

discussed and wiring requirements

explained.

Details are based upon the 2013 FRC rules.

Basic Electricity Ohm's Law

Voltage = Current * Resistance or

Current = Voltage / Resistance or

Resistance = Voltage / Current

Batteries in series add their voltages, not their currents

Batteries in parallel add their current, not their voltages

Resistances or loads in series block more current and split voltage

Resistances or loads in parallel use more current and share the voltage

Series Parallel Example

Determine voltage and current in each part of the circuit

Parallel

resistance =

R1*R2/(R1+R2)

Power Power is calculated by multiplying voltage by

current to get watts, E x I = W

Amp hour ratings of batteries are only useful if based on a time to discharge. To discharge faster, derate by 10 to 30% or more as the battery ages

So with a 17 amp hour battery discharging over 2.25 minutes is capable of delivering:

17 * 60 / (1.3 * 2.25) = 348 amps continuously

While this might seem like a lot, one CIM motor has a 344 amp stall current. A 4-wheel drive with 4 CIM motors might each draw close to 40 amps.

Pieces Parts Battery, Wire, Main Circuit Breaker, Lugs

Power Distribution Board (PDB), Fuses, More Wire,

Terminals and Connectors

cRIO, Digital Modules, Analog Modules

Digital Sidecar, D-sub Cable, Wiring Connections

Analog Breakout Board, Cabling

Bridge, Power Converter, Cabling

Jag, Victor, Talon, Vex, Servo, Power Wiring, Motor

Wiring, Signal Wiring

Compressor, Solenoid, Spike

Camera, Power, Ethernet

Power Wiring Block Diagram

This is an ungrounded system!

Battery to PDB Battery, NP18-12 12VDC

or ES17-12

Wire, 6 guage

Anderson Connectors

Main 120A Circuit Breaker

Lugs, KPA4CUNPL or YAZV6CTC14FX

Electrically insulate the cable connections with heat shrink or electrical tape

Battery to PDB Wiring Schematic

PDB Incoming Power, 6mm Shanks

Snap Action Maxi-Style breakers, press-in

Up to 8 12VDC 40A circuits, WAGO terminations for one 6

to 12 ga. wire

12 additional 12VDC circuits up to 30A each, WAGO

terminations for one 10 to 24 ga. wire

24VDC connection for cRIO

5VDC for Ethernet Camera

12VDC for Ethernet Bridge

PDB Connectors

2x

To cRIO

To E-net Camera

To PS for E-net Bridge

WAGO Block Wire Insertion

Spring-loaded

contacts

Use a screw-driver

to open a space

to insert a single

wire.

cRIO Hardware

cRIO Chassis with Modules

cRIO Chassis

NI9201 Analog in Slot 1

NI9203 Digital I/O in Slot 2

NI9472 Digital Out in Slot 3

Power Wiring

Ethernet Port

Serial

Port

Must be mounted such that the metal chassis does not contact the metal of the robot frame.

Leave Slot 4 empty

RJ 45 Ethernet

Cable

Analog Breakout Board

Mounts to NI9201 Analog in Slot 1

12 VDC Power from PDB using a 5A breaker

Jumper chooses use of AI8

Here for monitoring battery voltage

Input wiring uses standard

3-pin PWM cables

and provides 5VDC

power to analog devices

Example Analog Device Wiring

Start with a standard 3-pin PWM cable

Attach to the analog breakout board

Attach to the rate row of pins on the Gyro making sure the

ground wire is closest to the corner of the circuit board

Digital Sidecar (DSC)

Allows device connections to NI9403 Digital I/O

Module in cRIO chassis

Uses 37-pin ribbon or shielded cable from module to

this board

Operates on 12VDC

12 VDC Power

Wiring,

20A Circuit

Robot Signal

Light

Not used in FRC

GPIO Relay Outputs

PWM Outputs

Robot Signal Light (RSL) Wiring

Use 2-wire cable from Digital Sidecar to RSL

Cut connector off of cable end at RSL and connect

(-) to center (N), (+) to (La) or (Lb), and jumper between

(La) and (Lb)

RSL connection on Digital Sidecar has plus and minus

terminals. Make this connection last.

Lb

La N

Example Digital Input Wiring Limit Switch Has common connection for Gnd (-) Has N.O. and N.C. connections for Signal

Gnd (-)

+5VDC

Signal

When activated, Limit Switch changes common connection from N.C. terminal to N.O. terminal

not needed

Example Line Sensor Wiring

Blue wire to (-)

Brown wire to +24VDC on Solenoid Breakout Board

White or Black wire to GPIO most inboard pin

– White is Dark Operate (D.O.)

– Black is Light Operate (L.O.)

Operates on 11 – 30 VDC

Digital Output Wiring Digital Outputs provide the ability to turn on a device like an LED light

Gnd (-)

+5VDC

Signal

not needed

Relay Output Wiring

Relay Outputs provide forward, reverse and off signals suitable for a Spike relay. They are actually two relays on three pins. So can be used to control two different outputs each referenced to the same Gnd.

Gnd (-)

Reverse

Forward

PWM/Servo Output Wiring

Servos require use of jumper adjacent to PWM cable connection. Non-servo PWM devices must not have this jumper installed.

Jumper

(-) closest to edge, 6VDC on center pin, signal on most inboard pin

Solenoid Breakout Board

Mounts on NI9472 Module in Slot 3

Provides (8) 1A Digital Outputs, 21W Max. Total Load

12 VDC Power from PDB using a 10A breaker

or 24VDC Power from PDB connector that powers

cRIO

Output wiring uses standard

2-pin cables

and switches 12 or 24VDC

power to devices

Solenoid Output Wiring Solenoid Outputs provide the ability to turn on devices like double solenoid valves (requires 24VDC)

Gnd (-)

Output

DC Motor Controllers

Jag – Best for fine low-

speed motor control

Victor – Supports higher

current applications

Talon – Direct replacement

for Victor

Vex – for small loads

Jag on PWM

Tan or gray is older version, black is latest

PWM cable

Jag on CAN 2 Methods:

Serial

Ethernet with 2CAN module

Daisy Chain to more Jags

RJ12

RJ45 RJ12

RJ12

RJ45

100 ohm resistor across center contacts of RJ12 connector of last Jag to terminate CAN bus

RJ45

RJ12

RJ12

Victor/Talon on PWM The wiring and functionality of the Victors are the same as

the Talons

The Talons are new and more robust. They are sealed.

PWM cable

Fan wires

Jumper for Coast or Brake

VEX Motor Wiring

Uses 6VDC from Digital Sidecar so jumper must be installed.

Jumper

(-) closest to edge, 6VDC on center pin, signal on most inboard pin

Wireless Bridge

`

12V to 5VDC

Power

Converter

DAP-1522 LinkSys Bridge

Ethernet cable

Ethernet Camera

DAP-1522 LinkSys Bridge

Ethernet cable

Axis 206 Camera

Acknowledgements/References Team 358 has an excellent web document with many of the same topics

covered in this presentation

http://team358.org/files/programming/ControlSystem2009-

/components.php

Section 4, “The Robot”, Rules 34 - 74 for the 2013 FRC game

FRC Data Sheets on

Power Distribution Board

Digital Sidecar

Analog Breakout Board

Solenoid Breakout Board

Jag (Black) Getting Started Manual from

http://www.ti.com/lit/ug/spmu131b/spmu131b.pdf