MATE Triggerfish Trouble Shooting the Sabertooth

2X5 Motor Controller

Include Files & Display Declaration

2

ROV Type and Variable Defs

3

Setup() Routine

4

Acquire and Scale Horizontal Joystick

5

Acquire and Scale Vertical Joystick

6

Status Display

7

Values to SaberTooth Controllers

8

Send the Values

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Step 4 – Output to the Motors

What You Should See 1) Turn on the ROV power, the status light

should be blue on the Sabertooth. 1) With your multimeter set on VOLTS DC

touch the red multimeter probe to the M1A screw top and the black multimeter probe to M1B screw top. Wiggle the joystick for the S1 input and you should see the voltage change from approximately +11.5VDC to -11.5VDC.

1) Repeat step 3 for the M2A and M2B

motor connections.

The next step is to check the output that goes from the Sabertooth to the motor tether wires. The motor tether wires should still be disconnected from the Sabertooth.

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Step 5A: Motor Tether Connections

If you have completed through step 4 and obtained all the desired readings then congratulations the Sabertooth is working properly.

Though, unfortunately you still could have issues with the tether connections to the motors. Sadly this is the most common issue and the biggest source of poor ROV performance. Testing the Motor Tether connections

The easiest way to test the tether wiring is to measure the resistance across each set of tether wires going to a motor. Set up your multimeter to measure resistance on its lowest setting (typically 200 ohms Hook one of the multimeter leads one of the motor tether wires and the other end of the multimeter probe to the other motor tether wire. You should get a reading between 3-6 ohms.

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Step 5B: Bad Motor Connections - OPEN

There are two kinds of faulty tether motor connections; bad connections that result in high resistance and reduce the power to the motor and shorts were the motor will not work at all The “Wire Splices” power point describes how to make good water proof connections.

Bad Connections – High Ohms Bad motor tether connections can result from not properly soldering the motor and tether wires together. As the wires wiggle around or get pulled the connection get worse and worse and can ultimately completely separate to create an open circuit. Another source of a bad motor connection is corrosion due to pool water leaking into the wire connections. Over time the corrosion can completely eat through the wires.

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Step 5C: Bad Motor Connections - SHORT

The other type of bad motor tether connections is a short. A short is when the metal from the inside of the two motor or tether wires touches together. Keep in mind water conducts electricity so if both of the motor wire connections are not waterproof and are not touching then a weak short can develop resulting in poor motor performance. A range of consequences can occur if the motor tether wires become shorted.

Bad Connections – Short The best outcome from a short in the motor tether wires is the Sabertooth will turn itself off, due to the high current, and the Sabertooth status light will go red. Your controls will not work properly until the short is cleared. The worst outcome from a short in the motor tether wires is when the Sabertooth burns up. You will know when you smell it.

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