*M

Here’s a list of Instrumentation abbreviations starting with the letter “M”, commonly used in P&IDs, datasheets, control systems, and field instrumentation.

M: Motor / Measurement / Meter (context dependent)
MA: Motor Alarm / Measurement Alarm
MAC: Motor Alarm Controller / Measurement Alarm Controller
MAM: Motor Alarm Module
MB: Motor Breaker / Measuring Bus
MBC: Motor Breaker Controller / Measuring Bus Controller
MC: Motor Controller / Measurement Controller
MCA: Motor Control Assembly
MCC: Motor Control Center / Motor Control Cabinet
MCD: Motor Control Device
MCM: Motor Control Module
MCP: Motor Control Panel
MCS: Motor Control System
MD: Measurement Device / Motor Drive
MDC: Measurement Device Controller
MDD: Motor Drive Device
MDE: Measurement Device Element
ME: Measurement Element / Motor Element
MF: Magnetic Flow / Motor Feedback / Measurement Filter
MFC: Mass Flow Controller / Magnetic Flow Controller
MFD: Mass Flow Device / Measurement Flow Device
MFM: Mass Flow Meter / Measurement Flow Module
MG: Motor Generator / Measuring Gauge
MH: Motor Heater
MI: Measurement Indicator / Motor Indicator
MIC: Measurement Indicating Controller
MIM: Measurement Interface Module / Motor Interface Module
ML: Measurement Level / Motor Load
MLA: Measurement Level Alarm
MLC: Measurement Level Controller
MLI: Measurement Level Indicator
MLT: Measurement Level Transmitter
MM: Measurement Module / Motor Module
MMC: Measurement Module Controller
MN: Motor Neutral / Measurement Node
MO: Motor Output / Measurement Output
MOC: Motor Output Controller
MOM: Motor Output Module
MP: Measurement Point / Motor Point / Main Panel
MPC: Measurement / Motor Point Controller
MPD: Measurement Pressure Device
MPI: Measurement Pressure Indicator
MPT: Measurement Pressure Transmitter
MR: Measurement Recorder / Motor Relay
MRC: Measurement Recorder Controller / Motor Relay Controller
MRD: Measurement Relay Device
MS: Measurement Switch / Motor Switch
MSC: Measurement Switch Controller
MSD: Motor Shutdown Device / Measurement Shutdown Device
MSI: Measurement Status Indicator
MSM: Measurement Signal Module
MT: Measurement Transmitter / Motor Transmitter
MTC: Measurement Temperature Controller
MTD: Measurement Trip Device / Motor Trip Device
MTI: Measurement Temperature Indicator
MTT: Measurement Temperature Transmitter
MV: Motor Valve / Measurement Valve
MVC: Motor Valve Controller / Measurement Valve Controller
MVM: Motor Valve Module / Measurement Valve Module
MW: Motor Wiring / Measurement Wiring