Hi I am using sabertooth 2x32 with two wheelchair motors and radiolink T8FB transmitter. When the transmitter is on both motors work fine, but when I switch the transmitter off, one motor turns off but the other keeps turning. It is always the motor 2. I am new to this project so if anyone has any idea how to tune the system I would appreciate some help.
Thank you
M
Hi malg,
You should always power-off the wheelchair before the radio transmitter.
The signal on the Receiver is not updated when you power-off the Transmitter and could even be set to a pre-defines called “Failsafe”.
“FAIL SAFE”:
F/S data,set responses in case of loss of signal or low Rx voltage(in percentage). Each channel can be set independently.
• The NOR (normal) setting holds the servo in its last commanded position.
• The F/S (Fail Safe) function moves each servo to a predetermined position.
• NOTE: the setting of the throttle’s F/S also applies to the low battery voltage.
• The F/S is used in certain competitions to spin the aircraft to the ground prior to flying away
and doing potential damage elsewhere. Conversely, may also be used to go to neutral on all
servos, hopefully keeping the plane flying as long as possible. 0 means throttle at the lowest position, 50
Actually, as I mentioned in my original post, I am using wheelchair motors rather than a wheelchair itself. It’s just that wheelchair motors are quite powerful hence my choice of motors. They are not actually attached to a wheelchair. I have also read the manual and played around with the F/S but the problems still exists.
I was hoping that someone on this forum came across this problem while using the RadioLink T8FB.
M
Having the wheelchair or not will not change anything.
You should never disconnect the Transmitter while the Sabertooth is still powered. As for FailSafe, you might want to set it such that the Receiver send centered signals when in this mode (1500us)
With all due respect, I am trying to safeguard the motors in case of transmitter failure in which case the sabertooth would be powered. I am using a vehicle not an aircraft. When the transmitter fails one engine stops and the other does not. I am trying to find a fail safe settings that cuts off both motors when the transmitter is off. I am new to this and have no idea what 1500us means.
M
The Receiver when going in Fail-Safe is still sending signals to the outputs.
It’s possible to re-program the Transmitter with the included adapter for the Fail-Safe behavior.
Yes I have been playing with those setting and have not got there yet. Do I need to rebind my receiver every time I make changes?
M
Should not be needed.
Do you have any “RC” servos to test the actual signal that is sent ? You can possibly connect by USB to the Sabertooth and see the signals ?
No I don’t have the RC servos and you are right I probably will have to get one to test the system. Thank you, that should be my next step.
M
