One of my machines has an electrical setup roughly as shown.
There are a couple of 90VDC 1/10 HP motors being PWM'd at approximately 20% duty cycle at 7KHz. They're probably consuming less than 1.5 amps each. The machine has been working fine for a while, but recently the MCU controller has been getting noisy signals from the inductive sensors, and hence it has been misbehaving.
Unfortunately, I could not find an off-the-shelf cable and connector harness for the sensors that is also shielded. And so the lines running from the sensors to the distribution box are ordinary 24ga three-conductor wire for each sensor. And even worse is that those wires run in parallel with the cables powering the motors through the same plastic conduit chain. Once the sensor's wires reach the distribution box, they are then connected to a single multi-conductor shielded wire all the way to the MCU, where its shield is connected to ground. The other side of said wire (the side in the distribution box) has been left floating so as to avoid possible ground loops.
Question, would it be better if the wires feeding the motors were also shielded so as to contain whatever EMI is being produced? If so, should their shield be grounded at both sides, or at one side only?
Would changing the sensor's unshielded cables for shielded ones solve the problem?
@MaxHeadRoom
There are a couple of 90VDC 1/10 HP motors being PWM'd at approximately 20% duty cycle at 7KHz. They're probably consuming less than 1.5 amps each. The machine has been working fine for a while, but recently the MCU controller has been getting noisy signals from the inductive sensors, and hence it has been misbehaving.
Unfortunately, I could not find an off-the-shelf cable and connector harness for the sensors that is also shielded. And so the lines running from the sensors to the distribution box are ordinary 24ga three-conductor wire for each sensor. And even worse is that those wires run in parallel with the cables powering the motors through the same plastic conduit chain. Once the sensor's wires reach the distribution box, they are then connected to a single multi-conductor shielded wire all the way to the MCU, where its shield is connected to ground. The other side of said wire (the side in the distribution box) has been left floating so as to avoid possible ground loops.
Question, would it be better if the wires feeding the motors were also shielded so as to contain whatever EMI is being produced? If so, should their shield be grounded at both sides, or at one side only?
Would changing the sensor's unshielded cables for shielded ones solve the problem?
@MaxHeadRoom