What are the basic principles of shielding and grounding for instrument cables?

Shielding and grounding principles: use shielded cables for analog signals (prevents pickup of electromagnetic interference), ground shield at one end only (prevents ground loop currents through shield), typically ground at control room end (single-point ground), keep signal cables separated from power cables, and use twisted pair cables (cancels induced noise). Proper grounding hierarchy: instrument signal grounds separate from power grounds, star-point grounding for sensitive circuits, and low-impedance ground connections. Poor grounding causes noise, offset errors, and intermittent problems.