*O

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

O: Output / Operator / Oil (context dependent)
OA: Output Alarm / Operator Alarm
OAC: Output Alarm Controller / Operator Alarm Controller
OAM: Output Alarm Module
OB: Output Bus / Oil Burner
OBC: Output Bus Controller / Oil Burner Controller
OC: Output Controller / Operator Controller
OCA: Output Control Assembly
OCC: Output Control Cabinet
OCD: Output Control Device
OCM: Output Control Module
OCP: Output Control Panel
OCS: Output Control System
OD: Output Device / Oil Detector
ODC: Output Device Controller / Oil Detector Controller
ODD: Output Device Device
ODS: Oil Detection System
OE: Output Element / Operator Element
OF: Oil Flow / Output Filter
OFC: Oil Flow Controller / Output Filter Controller
OFM: Oil Flow Meter / Output Flow Module
OG: Oil Gauge / Operator Gauge
OH: Output High / Oil Heater
OI: Output Indicator / Operator Indicator
OIC: Output Indicating Controller
OIM: Output Interface Module / Operator Interface Module
OL: Output Low / Oil Level
OLA: Output Low Alarm / Oil Level Alarm
OLC: Output Low Controller / Oil Level Controller
OLI: Output Low Indicator / Oil Level Indicator
OLT: Output Low Transmitter / Oil Level Transmitter
OM: Output Module / Operator Module
OMC: Output Module Controller
ON: Operator Node / Output Node
OO: Operator Output / Output Output
OOC: Operator Output Controller
OOM: Operator Output Module
OP: Operator Panel / Output Point
OPC: Operator Panel Controller / Output Point Controller
OPD: Operator Pressure Device
OPI: Operator Pressure Indicator
OPT: Operator Pressure Transmitter
OR: Output Recorder / Operator Relay
ORC: Output Recorder Controller / Operator Relay Controller
ORD: Output Relay Device
OS: Output Switch / Operator Switch
OSC: Output Switch Controller
OSD: Output Shutdown Device
OSI: Output Status Indicator
OSM: Output Signal Module / Operator Signal Module
OT: Output Transmitter / Operator Transmitter
OTC: Output Temperature Controller
OTD: Output Trip Device / Operator Trip Device
OTI: Output Temperature Indicator
OTT: Output Temperature Transmitter
OV: Output Valve / Operator Valve
OVC: Output Valve Controller
OVM: Output Valve Module