Troubleshooting
Noise & Interference
Noise & Interference in industrial control systems — covering 5 topic areas in the CurryControls.com controls and automation knowledge hub.
Written guides in this section
Full references, procedures, and diagnostic guides published under Noise & Interference.
VFD Noise on Analog Signals
Analog readings that jump or wander when a drive runs, and speed references that make a drive hunt: how the drive output couples into signal wiring, why the input turns kilohertz noise into a slow wander, the tests that pin it on the drive, and the fixes.
10 min readUpdated Sep 5, 2026
Radio Frequency Interference
Readings that jump when a handheld radio is keyed, inputs that flicker near a telemetry antenna, transmitters that drift beside a modem: how radio energy gets into control circuits, how to prove it with the radio itself, and the fixes.
9 min readUpdated Sep 5, 2026
Common-Mode Noise
Noise that rides on both conductors of a signal pair together, relative to ground: where it comes from, why a differential input rejects it only up to a limit, how to tell it from normal-mode noise with a scope, and the fixes that work.
9 min readUpdated Sep 5, 2026
Cable Routing Problems
Noise that comes from where a cable runs: signal cables sharing a conduit, tray, or wireway with power or drive cables, long parallel runs, and shallow crossings. How coupling works, the separations that prevent it, and how to find the shared path.
9 min readUpdated Sep 5, 2026
Unshielded Cable in a Noisy Run
The signal was run in plain conductors through a route full of power and drive cables, and now it is noisy. What unshielded cable cannot do, how to prove the cable is the problem before pulling a new one, and the options when replacing it is not possible.
9 min readUpdated Sep 5, 2026
Topics in this area
VFD Noise On Analog Signals
VFD Noise On Analog Signals — practical reference notes for controls engineers, integrators, and technicians working with noise & interference.
Radio Frequency Interference
Radio Frequency Interference — practical reference notes for controls engineers, integrators, and technicians working with noise & interference.
Common Mode Noise
Common Mode Noise — practical reference notes for controls engineers, integrators, and technicians working with noise & interference.
Cable Routing Problems
Cable Routing Problems — practical reference notes for controls engineers, integrators, and technicians working with noise & interference.
Unshielded Cable In A Noisy Run
Unshielded Cable In A Noisy Run — practical reference notes for controls engineers, integrators, and technicians working with noise & interference.
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