Hello How Come?;
Please take the time to study the document I suggested, as a starter. There is a complete chapter on Shileding, how it is done in a panel (granted it is for drives, but the main ideas are the same as for instrumentation) where it should be connected to protective earth (equipotential bonding).
When you have need of more details, or if this has confused you even more , come back to the forum.
Hope this helps,