8.3. USB connection loss¶
The most common cause of this kind of problem lies in grounding. To figure out why the USB connection is constantly lost, we suggest:
Dielectric as an insulator:
If the controller or positioner is attached to a metal table, the table can act as a conductor of parasitic currents.
These currents create electromagnetic interference that can affect the operation of electronics, causing errors, control failures, or signal distortion.
By placing a dielectric material, you break the unwanted electrical contact between the controller, the positioner and the metal table,
thereby eliminating the path for stray currents and reducing the likelihood of interference.
If the problem disappears after that, the cause will be determined.
Grounding loops:
When different devices are “connected” through a common metal table (or other conductor), a closed loop known as a ground loop can occur.
In such a loop, a parasitic current may flow due to a potential difference, which will lead to noise and unstable operation of the system.
It is assumed that the controller is grounded on two sides: through the power supply and through the computer.
The grounding on the computer side cannot be broken without a separate galvanic isolation module.
Power supplies are often made without grounding at the output. Standa power supplies are grounded.
As a quick system solution, it is proposed:
- Use an USB adapter with galvanic isolation on the USB cable from the computer side.
For example, USB Isolator Module ADUM3160 - Use an adapter between the socket and the controller power supply.
Example of a Plug Adapter - Non-Grounded (UP-6AE, 6 Pack)
As an additional solution, it is proposed:
- Change USB cable. Use verified USB cables only! Damaged or low-quality USB cable may cause improper controller operation, including motor rotation errors and errors of device recognition by PC operating system. Super short cables with thick wires and screening are ideal for sustainable connection;
- Change USB port;
- Change PC.
Note
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