Measuring signals in high noise environment

[Crazy_Engineer]

How do you accurately measure signals when there is a lot of EMF in the work area?  I am currently using my DS1054Z to try to measure signals on a project that involves relays.  Unfortunately switching the relays produce so much emf that my o-scope reads a few volts if the unconnected probes are anywhere near the board.

[Kleinstein]

As long as the signal to measure things get much better when the probe is connected. It is normal for the high impedance probe to pic up quite some signal from the environment, usually mainly 50/60 Hz mains frequency.

It might be with adding free-wheeling diodes if the relays are DC. Or snubbers if AC. Normally Relays don'T produce so much EMF trouble. Difficult are things like an arc lamp or arc-welding.

[Crazy_Engineer]

The relays have flyback diodes, and the probes are set to their lowest impedance.  Perhaps wrapping the probes in conductive tape will shield them from the EMF?

[CopperCone]

try removing the bayonet tip/hook from the probe, and disconnecting the ground wire. Do you still get pickup?