Instrumentation field troubleshooting — pressure transmitter issues (impulse line blockage, freeze-up, vapor lock, wet leg errors), temperature measurement errors (thermocouple drift, thermowell vibration/resonance, Strouhal number, immersion length, EMF errors), flow measurement errors (orifice plate fouling, Coriolis zero-drift, vortex low-flow cutoff, DP transmitter errors), level measurement issues (displacer errors, radar false echoes, DP level with density changes), control loop issues (hunting, integral windup, derivative kick), grounding and electrical noise, 4-20 mA loop faults, HART communication, ISA S5.1 P&ID symbology.
