ROV 2017 Electrical Notes

Motor Controllers

Two motor controllers are used. The first is the Sabertooth 2x5 Motor Controller, which was used on Blue Puttee in 2016, and the Sabertooth 2x5 R/C Motor Controller. They essentially do the same thing, with the difference being that the R/C's have per-soldered connections for Channels and a "flip", and the standard ones don't and the DIP switch ON/OFF are different, as explained below. Either way, both are used in R/C or analog mode.

Sabertooth 2x5 Motor Controllers

Sabertooth 2x5 R/C Controllers

The pins on both devices are as follows:

B+/B-: "Battery" input. We put in 12V to B+, GND to B-

GND: Microcontroller Ground.

5V: A locally created 5V for powering the onboard microcontroller. DO NOT attach it to anything

S1/S2: Control inputs for each motor channel

M1A/M1B/M2A/M2B: The differential motor outputs, as controlled by S1 and S2.

Sabertooth 2x5 Motor Controllers DIP Switches

On the 2x5s, you'll see 6 switches. In 2016, we chose to use RC control because it's the same as the input the ESCs take.

Switch 1 & 2: Sets the input mode of the motor controllers. We use RC mode, obtained with 1=OFF, 2=ON

Switch 3: Lithium Cutoff Enable: When OFF, the switch will shut the motor controller down if it does not receive the proper voltage when running on Lithium Ion Batteries. Should be ON.

Switch 4: Mixed or independent motor control mode. We use independent, achieved with 4=OFF

Switch 5: Linear/Exponential Response. We use linear, achieved with 5=ON

Switch 6: R/C Mode/Microcontroller mode select. We had problems last year with microcontroller mode, and use R/C mode.

Sabertooth 2x5 R/C Controllers DIP Switches

On the 2x5 R/Cs, the 6 switches will be as follows:

Switch 1: Mixing mode. With switch 1 in the UP position, the controller is in mixed mode. Switch 1 in the DOWN position turns mixing mode off. Here we will switch to OFF.

Switch 2: Exponential. If switch 2 is in the UP position the controller will be in exponential mode, if Switch 2 is in the DOWN position exponential is disabled and the response is linear. We will switch this OFF, as we are using linear mode.

Switch 3: Lithium: Switch 3 in the DOWN position enables Lithium mode, for use with Lithium batteries. This will shut the controller down at 3.0 volts, preventing damage to a Lithium battery pack. However, we are not using batteries to power the motor controllers and therefore we will switch this UP to turn it ON.

Switch 4: Flip Control: Switch 4 in the UP position flips the signal if you want it to (it your robot flips upside down). Set switch 4 down to turn off.

Switch 5: Auto calibrate: In auto-calibrate mode the neutral position is read at power-up and the endpoints are automatically detected. Switch 5 in the DOWN position always uses 1000us for full reverse, 1500us for stop and 2000us for full forward. I don't think we need autocalibration, so switch DOWN.

Switch 6: Timeout: Switch 6 in the UP position enables timeout. If no signal is received for 1 second, the controller turns the motors off. If Switch 6 is in the DOWN position, timeout is disabled and the controller will run at the last commanded speed until a new command is given. We want the motors to time out if we lose control of the maestro so set this dip switch to UP.

NOTE: The RC Channels have the five volt signal inside the channel wire string (middle orange wire). This CANNOT BE CONNECTED TO THE MAESTRO. If it's connected, the motor controllers will not work.