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When I use RC to output a perfect RC waveform to S1 and S2 ports in sabertooth,it always lose control
and when I connect 3 0.1uF capacitors to the motor terminals and case,it is sometime lose control
and When I connect 2 0.1uF Cap to S1 and S2.1 out of 10 times it still loses control even I off my RC.
But when I off the RC it will stop 2 seconds then run again.
I really cannot figure out the reason,EMF and noise should be filtered out by Caps.
I doubt that is there anything wrong with the motor controller since the Input is correct and output is wrong?
How do you make sure it's a "perfect RC waveform"?When and how does it loose control andin what way?
How often?Does the behaviour change during the day?
Definitly add pull downs.
A few caps may not be enough! Did you twist the wiring pairs?
I used an oscilloscope the check and see the frequency and duty cycle are right.
[...] after I use transmitter to make the motor run I cannot stop it by stopping the transmitter,most likely the motor will run forward and i have to output a backward signal to stop the motor.This seems the motors are still under control but the be movement dosen't match the signal.
I have tried many ways to improve the behavior.Without Caps 90% it will free run without control.Adding Cap to motors terminals and case,it will be 50% and Adding Caps to S1 and S2(transmitter signal) ,it will be 10%.
Since I have off the transmitter the S1 and S2 cannot pick up the eletcrostatic I think and pull down resistor will not work for this case.
I only see the waveform when I on the transmitter,
I will try and see the waveform when I off it and try pull down first.I will let you know.
Quote from: Soeren on August 25, 2012, 12:43:51 PMA few caps may not be enough! Did you twist the wiring pairs?How to connect more than 3 Caps?Parallel the case and terminals? Twist the 5V and ground?
[...] Do you know how to improve the situation or disable the signal recreation system?
If switch 6 is in the UP position, then the Sabertooth is in standard R/C mode. This mode is designed to be used with a hobby-style transmitter and receiver. It automaticallycalibrates the control center and endpoints to maximize stick usage. It also enables a Timeout Failsafe, which will shut down the motors if the Sabertooth stops receiving correct signals from the receiver.
If switch 6 is set in the DOWN position, then Microcontroller mode is enabled. This disables the Timeout Failsafe and auto-calibration. This means that the Sabertooth will continue to drive the motor according to the last command until another command is given. If the control link is possible unreliable – like a radio - then this can be dangerous due to the robot not stopping.
By the way, what do you mean by twisting the wire,what wire and which part of wire should I twist.
The wire I m using is a single core normal jumper wire,it's diameter looks like 0.6-0.8mm.I have also tried 2-3 mm multicore wire and beside the increase in curent, the hehavior is still the same.