ISA Instrument Letters Identification
From Piping-Designer
Standard ISA Instrument Letter Identification
| First
Letter | Initial or
Measured Variable | Controller
Recording | Controller
Indicating | Controller
Blind | Controller
Self Actuated Control Valve | Readout Device
Recording | Readout Device
Indicating | Switch
/Alarm High | Switch
/Alarm Low | Switch
/Alarm Combo | Transmitter
Recording | Transmitter
Indicating | Transmitter
Blind | Solenoid,
Relay, Computing Device | Primary
Element | Test
Point | Well
or Probe | Viewing
Device, Glass | Safety
Device | Final
Element |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| A | Analysis | ARC | AIC | AC | AR | AI | ASH | ASL | ASHL | ART | AIT | AT | AY | AE | AP | ZW | AV | |||
| B | Burner | BRC | BIC | BC | BR | BI | BSH | BSL | BSHL | BRT | BIT | BT | BY | BE | BW | BG | BZ | |||
| C | User's Choice | |||||||||||||||||||
| D | User's Choice | |||||||||||||||||||
| E | Voltage | ERC | EIC | EC | ER | EI | ESH | ESL | ESHL | ERT | EIT | ET | EY | EE | EZ | |||||
| F | Flow Rate | FRC | FIC | FC | FCV | FR | FI | FSH | FSL | FSHL | FRT | FIT | FT | FY | FE | FP | FG | FV | ||
| FQ | Flow Quality | FQRC | FQIC | FQR | FQI | FQSH | FQSL | FQIT | FQT | FQY | FQE | FQV | ||||||||
| FF | Flow Ratio | FFRC | FFIC | FFC | FFR | FFI | FFSH | FFSL | FE | FFV | ||||||||||
| G | User's Choice | |||||||||||||||||||
| H | Hand | HIC | HC | HS | HV | |||||||||||||||
| I | Current | IRC | IIC | IR | II | ISH | ISL | ISHL | IRT | IIT | IT | IV | IE | IZ | ||||||
| J | Power | JRC | JIC | JR | JI | JSH | JSL | JSHL | JRT | JIT | JT | JY | JE | JV | ||||||
| K | Time | KRC | KIC | KC | KCV | KR | KI | KSH | KSL | KSHL | KRT | KIT | KT | KY | KE | KV | ||||
| L | Level | LRC | LIC | LC | LCV | LR | LI | LSH | LSI | LSHI | LRT | LIT | LT | LY | LE | LW | LG | LV | ||
| M | User's Choice | |||||||||||||||||||
| N | User's Choice | |||||||||||||||||||
| O | User's Choice | |||||||||||||||||||
| P | Pressure Vacuum | PRC | PIC | PC | PCV | PR | PI | PSH | PSL | PSHL | PRT | PIT | PI | PY | PE | PP | PSV | PV | ||
| PD | Pressure Differential | PDRC | PDIC | PDC | PDCV | PDR | PDI | PDSH | PDSL | PDRT | PDIT | PDT | PDY | PE | PP | PDY | ||||
| Q | Quality | QRC | QIC | QR | QI | QSH | QSL | QSHL | QRT | QIT | QT | QY | QE | QZ | ||||||
| R | Radiation | RRC | RIC | RC | RR | RI | RSH | RSL | RSHL | RRT | RIT | RT | RY | RE | RW | RZ | ||||
| S | Speed Frequency | SRC | SIC | SC | SCV | SR | SI | SSH | SSL | SSHL | SRT | SIT | ST | SY | SE | SV | ||||
| T | Temperature | TRC | TIC | TC | TCV | TR | TI | TSH | TSL | TSHL | TRT | TIT | TT | TY | TE | TP | TW | TSE | TV | |
| TD | Temperature Differential | TDRC | TDIC | TDC | TDCV | TDR | TDI | TDSH | TDSL | TDRT | TDIT | TDT | TDY | TE | TP | TW | TDV | |||
| U | Multivariable | UR | UI | UY | UY | |||||||||||||||
| V | Vibration | VR | VI | VSH | VSL | VSHL | VRT | VIT | VT | VY | VE | VZ | ||||||||
| W | Weight Force | WRC | WIC | WC | WCV | WR | WI | WSH | WSL | WSHL | WRT | WIT | WT | WY | WE | WZ | ||||
| WD | Weight Force Differential | WDRC | WDIC | WDC | WDCV | WDR | WDI | WDSH | WDSL | WDRT | WDIT | WDT | WDY | WE | WDZ | |||||
| X | Unclassified | |||||||||||||||||||
| Y | Event-State Presence | YIC | YC | YII | YI | YSH | YSL | YT | YY | YE | YZ | |||||||||
| Z | Position Dimension | ZRC | ZIC | ZC | ZCV | ZH | ZI | ZSH | ZSL | ZSHL | ZRT | ZIT | ZT | ZY | ZE | ZV | ||||
| ZD | Gauge Deviation | ZDRC | ZDIC | ZDC | ZDCV | ZDR | ZID | ZDSH | ZDSL | ZDRT | ZDIT | ZDT | ZDY | ZDE | ZDV |
Other Possible Combinations:
- FQ (Restriction Orifice)
- FRQ, HIK (Control Stations)
- FX (Accessories)
- TJR (Scanning Recorder)
- LLH (Pilot Light)
- PFR (Ratio)
- KQI (Running Time Indicator)
- QQI (Indicating Counter)
- WKIC (Rate-of-Weight-Loss Controller)
- HMS (Hand Momentum Switch)
- A (Alarm), a announcing device, can be used in the same fashion as S (Switch), a actuating device.
