I have a servo motor operating a throttle which is attached to an angle sensor to read how much of the throttle is open. I currently have my servo powered externally via a PC PSU as the T7 5V voltage sources (VS on the board) don't seem to have the required current for the servo.
My problem is that I am reading huge spikes of noise on the angle sensor, the largest of which can be 10% of full throttle. The spike is very short lived but quite frequent and causes the PID control of the servo to be very difficult to calibrate properly. I have located the general source of the problem to be the servo As everything functions noise free without it. My question is related to grounding as I believe this to be the cause of the issue, currently I have wired the power lines (+5VDC and GND) to a 5V source on the external power supply and the signal line is wired to a PWM capable DIO channel. The ground of the servo and the external power supply are not connected, I have done some research into this situation and have found that the grounds should all be connected to the data acquisition board (T7). When I connect my grounds together the servo ceases to function.
Hopefully my explanation makes sense and if you have any idea where this noise could be coming from or why my servo ceases to function when the grounds are connected to the T7 I would greatly appreciate it.
Thanks, Stuart.
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Is this an RC style servo where you give it a 50 Hz signal with a duty cycle of 1-2 ms to indicate 0 to 100%?
What sort of power supply do you have for the servo? AC-DC supply? Is it connected to anything else?
Can you tell us more about the angle sensor?
If you have anything else connected to the T7, can you remove those connections to avoid extra complications for initial troubleshooting?
Are you using USB or Ethernet? If Ethernet, how are you powering the T7?
Hi sorry for the long reply time. I have been extensively searching for my problem. In the end this problem wasn't caused by a labview or labjack error, it turned out that my power source for the majority of the sensors which is a PC PSU was outputting a very noisy voltage. This noisy voltage was effecting my potentiometer that controlled the servo which lead to all my problems.
I have since moved all the 5V sensors that I can to run off of the labjack 5V source, this is working great.
My PSU only produces these noisy voltages when the engine is running on the dyno setup. I will continue to investigate.
Sorry to perhaps of wasted your time.,
Stuart.