ISA 5.1 Table 2 - Typical Letter Combinations

Written by Jerry Ratzlaff on . Posted in Instrument Society of America

 

 ControllerReadout DevicesSwitches and Alarm Devices*Transmitters 
First LetterInitial or Measured VariableRecordingIndicatingBlindSelf Actuated Control ValveRecordingIndicatingHighLowComboRecordingIndicatingBlindSolenoid, Relay, Computing DevicePrimary ElementTest PointWell or ProbeViewing Device, GlassSafety DeviceFinal Element
A Analysis ARC AIC AC - AR AI ASH ASL ASHL ART AIT AT AY AE AP AW     AV
B Burner/ Combustion 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 IY 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 LSL 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 PT PY PE PP - - PSV PV
PD Pressure, Differential PDRC PDIC PDC PDCV PDR PDI PDSH PDSL - PDRT PDIT PDT PDY PE PP - - - PDV
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 - - - - - UV
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 - YR YI YSH YSL - - - YT YY YE - - - - YZ
Z Position/ Dimension ZRC ZIC ZC ZCV ZR ZI ZSH ZSL ZSHL ZRT ZIT ZT ZY ZE - - - - ZV
ZD Gauging/ Deviation ZDRC ZDIC ZDC ZDCV ZDR ZDI 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.

standards

  • ISA Standards
    • ISA 5.1 - Instrumentation Symbols and Identification