Control bus- can a loop be used?
Control bus- can a loop be used?
(OP)
Suppose one wishes to control a series of electric motors via a control bus such as serial, ethernet, RS232, whatever... can these devices be arranged in a loop?
Think of an electric fence around a field... with the control signal being sent out both directions down the fence... each post representing a controlled motor.
Can this be done, or would the signal from each side confuse some of the controlled items? A possible advantage of this scheme is that if the control cable were severed once, the controlled units would still have control feed from the other portion of the loop. In the event that a loss of control would be, shall we say, extremely painful to bear, it'd be nice to add some measure of backup like this.
Of course each motor should also have a fail-safe mode to revert to in the event that loss of control signal is detected, minimizing the pain that must be borne.
Think of an electric fence around a field... with the control signal being sent out both directions down the fence... each post representing a controlled motor.
Can this be done, or would the signal from each side confuse some of the controlled items? A possible advantage of this scheme is that if the control cable were severed once, the controlled units would still have control feed from the other portion of the loop. In the event that a loss of control would be, shall we say, extremely painful to bear, it'd be nice to add some measure of backup like this.
Of course each motor should also have a fail-safe mode to revert to in the event that loss of control signal is detected, minimizing the pain that must be borne.





RE: Control bus- can a loop be used?
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RE: Control bus- can a loop be used?
Do you mean VFD's or other devices controlling the motors?
and what is your definition of control?
RE: Control bus- can a loop be used?
As for the type of control, let's say similar to VFD- or specifying a position or other operating parameter via a 1-10V signal [subject to noise], or 4-20mA type signal... or the digital equivalent.
Basically, provide half the control signal and expect each motor to do half of whatever it is it does. Open something, go to a specified RPM, etc.
RE: Control bus- can a loop be used?