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We have already seen how the letters A – Z are combined in instrumentation diagrams to give process instruments unique function and identification in Instrument Abbreviations Used in Instrumentation Diagrams (P&IDs). Since the subject of process instrumentation diagrams is versatile and at the heart of understanding key industrial processes, we present further examples of instrument abbreviations as defined in the ISA 5.1 standard for symbols used in P&IDs. In the table presented below, we have:
(a) A column for the first letter denoting the process variable
(b) A second column denoting the initiating or measured variable
(c) A third column for controllers of various degrees – recording, indicating, blind (denotes a controller without a modifying function such as recording or indicating) and self-actuated control valves designed to regulate diverse process variables
(d) A fourth column for readout devices which can either be recording or indicating as the case maybe.
The table for instrument abbreviations shows many possible combinations for any kind of instrument measuring the defined variables as denoted by the first letter in the first column.
First Letter
|
Initiating or Measured Variable
|
Controllers
|
Read out Devices
|
||||
Recording
|
Indicating
|
Blind
|
Self-Acutated Control Valves
|
Recording
|
Indicating
|
||
| A | Analysis | ARC | AIC | AC | AR | AI | |
| B | Burner/Combustion | BRC | BIC | BC | BR | BI | |
| C | User's Choice | ||||||
| D | User's Choice | ||||||
| E | Voltage | ERC | EIC | EC | ER | EI | |
| F | Flow Rate | FRC | FIC | FC | FCV, FICV | FR | FI |
| FQ | Flow Quantity | FQRC | FQIC | FQR | FQI | ||
| FF | Flow Ratio | FFRC | FFIC | FFC | FFR | FFI | |
| G | User's Choice | ||||||
| H | Hand | HIC | HC | ||||
| I | Current | IRC | IIC | IR | II | ||
| J | Power | JRC | JIC | JR | JI | ||
| K | Time | KRC | KIC | KC | KCV | KR | KI |
| L | Level | LRC | LIC | LC | LCV | LR | LI |
| M | User's Choice | ||||||
| N | User's Choice | ||||||
| O | User's Choice | ||||||
| P | Pressure/Vacuum | PRC | PIC | PC | PCV | PR | PI |
| PD | Pressure, Differential | PDRC | PDIC | PDC | PDCV | PDR | PDI |
| Q | Quantity | QRC | QIC | QR | QI | ||
| R | Radiation | RRC | RIC | RC | RR | RI | |
| S | Speed/Frequency | SRC | SIC | SC | SCV | SR | SI |
| T | Temperature | TRC | TIC | TC | TCV | TR | TI |
| TD | Temperature, Differential | TDRC | TDIC | TDC | TDCV | TDR | TDI |
| U | Multivariable | ||||||
| V | Vibration/Machinery Analysis | ||||||
| W | Weight/Force | WRC | WIC | WC | WCV | WR | WI |
| WD | Weight/Force, Differential | WDRC | WDIC | WDC | WDCV | WDR | WDI |
| X | Unclassified | Cell | Cell | Cell | Cell | Cell | Cell |
| Y | Event/State/Presence | YIC | YC | YR | YI | ||
| Z | Position/Dimension | ZRC | ZIC | ZC | ZCV | ZR | ZI |
| ZD | Gauging/Deviation | ZDRC | ZDIC | ZDC | ZDCV | ZDR | ZDI |
