INSTRUMENTATION ABBREVIATIONS

INSTRUMENTATION ABBREVIATIONS, NOMENCLATURE, ACRONYMS,   AND SYMBOLS

2D3D	two-dimensional three-dimensionalA	amp AMPS AMS	ampere; also Aadvanced mobile phone systemasset  management  solutions  or  analyzer maintenance solutions
a	acceleration	AO	analog output
A	(1) area; (2) ampere, symbol for basic SI	AOTF	acousto-optical tunable filters
	unit of electric current; (3) admittance	AP	access point
Å AA	angstrom (= 10-10  m)atomic absorption	APCAPDU	automatic process controlapplication (layer) protocol data unit
AAS	atomic absorption spectrometer	API	application programming interface or abso-
abs	absolute (e.g., value)		lute performance index
AC	alternating current	°API	API degrees of liquid density
ACFM	actual cubic feet per minute; volumetric	APM	application pulse modulation
	flow at actual conditions in cubic feet per	AR	autoregressive
ACL	minute (= 28.32 alpm)asynchronous connectionless	ARAARIMA	alarm response analysisautoregressive integrated moving average
ACMH	actual cubic meters per hour	ARP	address resolution protocol
ACMM	actual cubic meters per minute	ASCII	American Standard Code for Information
ACS	analyzer control system		Interchange
ACSL	advanced continuous simulation language	AS-i	actuator sensor interface
A/D	analog  to  digital,  also  analog-to-digital	ASIC	application-specific integrated circuit
	converter	ASK	amplitude shift keying
AD	actuation depth	asym	asymmetrical; not symmetrical
ADC	analog-to-digital converter	ATG	automatic tank gauging
ADIS	approved for draft international standard	atm	atmosphere (= 14.7 psi)
	circulation	ATP	adenosine triphosphate
A&E	alarm and event	ATR	attenuated total reflectance
AES	atomic emission spectrometer	AUI	attachment unit interface
AF, a-f	audio frequency	aux	auxiliary
AFD	adjustable frequency drive	AWG	American wire gauge
AGA3	American Gas Association Report No. 3
ai	Adobe IllustratorÒ		B
AI	analog input	b	dead time
a(k)	white noise	°Ba	balling degrees of liquid density
ALARA	as low as reasonably achievable	bar	(1) barometer; (2) unit of atmospheric pres-
ALARP	as low as reasonably practicable		sure measurement (= 100 kPa)
alpm	actual liters per minute	barg	bar gauge
alt	altitude	bbl	barrels (= 0.1589 m3)
AM	amplitude  modulated  or  actual  measure-	BCD	binary coded decimal
	ment	BCS	batch control system

°Bé BFO BFW bhp	Baumé degrees of liquid density beat frequency oscillatorboiler feedwaterbrake horsepower (= 746 W)	CENP CECFA	combustion engineering nuclear power Conformité Européne (European Confor- mity), applicable to electrical safety Continuous flow analyzer
°Bk	Barkometer degrees of liquid density	CFM, cfm,	cubic feet per minute (28.32 lpm)
blk	black (wiring code color for AC “hot” con-	ft3/min
	ductor)	CFR	Code of Federal Regulations
BMS	burner management system	CF/yr	cubic foot per year
BOD	biochemical oxygen demand	Ci	curie (= 3.7 ´ 1010 Bq)
bp, b.p.	boiling point	CI	cast iron
BPCS	basic process control system	CIM	computer integrated manufacturing
BPS, b/sec	bits per second	CIP	computer aided production or control and
BPSK	binary phase shift keying		information protocol (an application layer
Bq	becquerel, symbol for derived SI unit of		protocol supported by DeviceNet, Control-
	radioactivity, joules per kilogram, J/kg		Net, and Ethernet/IP)
°Br	Brix degrees of liquid density	CJ	cold junction
Btu	British thermal unit (= 1054 J)	CIP	clean in place
BWG	Birmingham wire gauge	CL1	electrically hazardous, Class 1, Division 1,
B2B	business to business		Groups C or D
		CLD	chemiluminescence detector
	C	CLP	closed-loop potential factor
c	(1) velocity of light in vacuum (3 ´ 108m/s); (2) centi, prefix meaning 0.01	cmCM	centimeter (= 0.01 m)condition  monitoring  or  communication
C	coulombs,  symbol  for  discharge  coeffi-		(interface) module
	cient, capacitance	CMF	Coriolis mass flowmeter
°Cca.	Celsius degrees of temperaturecirca  (about, approximately)	CMMS	computerized   maintenance   managementsystem
CAC	channel access code	CMPC	constrained multivariable predictive control
CAD	computer aided design	cmph, m3/h	cubic meter per hour
CalCAN	calorie (gram = 4.184 J); also g-calcontrol area network or control and auto-	CNICO	ControlNet Internationalcontroller output or carbon monoxide
	mation network	CO2	carbon dioxide
CARI	combustion air requirement index	CO2D	carbon dioxide demand
CATV	community antenna television (cable)	COD	chemical oxygen demand
ccCCD	cubic centimeter (= 10-6  m3)charge-coupled device	COFCOM	coefficient of hazecomponent object model
CCF	common  cause  failure  or  combination	COTS	commercial off-the-shelf
	capacity factor	cpm	cycles per minute; counts per minute
Ccm	cubic centimeter per minute	Co	cobalt
CCR	central control room	cos	cosine (trigonometric function)
Ccs	constant current source	cp, c.p.	(1)  candle  power,  (2)  circular  pitch,  (3)
CCS	computer control system or constant cur-		center of pressure (cp and ctp sometimes
	rent source		are used for centipoise)
CCTV	closed circuit television	cps	(1)  cycles  per  second  (hertz,  Hz);  (2)
CCW	counterclockwise		counts per second; (3) centipoise (= 0.001
CD	dangerous coverage factor		Pa·S)
cd	candela, symbol for basic SI unit of lumi-	CPS	computerized procedure system
	nous intensity	CPU	central processing unit
CD	compact disk or collision detector	CPVC	chlorinated polyvinyl chloride
CDDP	cellular digital data packet	CR	corrosion rate
CDF	cumulative distribution function	CRC	cyclical redundancy check or cyclic redun-
CDMA	code division multiple access		dancy code. (An error detection coding tech-
CDPD	cellular digital packet data		nique based on modulo-2 division. Some-
CDT	color detection tube		times misused to refer to a block check
CDTP	cold differential test pressure		sequence type of error detection coding.)
CEMS	continuous emissions monitoring system	CRDS	cavity ring-down spectroscopy

CRLF CRT	carriage return-line feed cathode ray tube	DIdia	discrete (digital) input diameter; also, D and f
Cs	cesium	DIAC	dedicated inquiry access code
CS	carbon steel	DIR	diffused infrared
CSL	car seal lock	DIS	draft international standard
CSMA/CD	carrier sense, multiple access with collision	DIX	Digital-Intel-Xerox  (DIX  is  the  original
	detection		specification that created the de factoEther-
CSO	car seal open		net standard. IEEE 802.3 came later, after
CSS	central supervisory station		Ethernet was established.)
cSt	centistoke	d(k)	unmeasured disturbance
CSTR	continuous-stirred tank reactor	D(k)	measured disturbance
CT	cooling tower or the product of C for dis-	DLE	data link escape
	infectant concentration and T for time of	DLL	dynamic link library
	contact in minutes	DMA	dynamic mechanical analyzer
CTDMA	concurrent time domain multiple access	DMM	digital multimeter
CTMP	chemi-thermo-mechanical pulp	DN	diameter normal, the internal diameter of
CVAAS	cold vapor atomic absorption spectroscopy		a pipe in rounded millimeters
CVF	circular variable filters	DO	dissolved oxygen or discrete (digital) output
cvs	comma-separated variables	DOAS	differential  optical  absorption  spectros-
CW	clockwise		copy
		d/p cell	differential pressure transmitter (a Foxboro
	D		trademark)
d	(1) derivative, (2) differential as in dx/dt,	DPD	N,N-diethyl-p-phenylenediamine
	(3) deci, prefix meaning 0.1, (4) depth, (5)	DPDT	double-pole double-throw (switch)
	day	dpi	dots per inch
D	diameter; also dia and f or derivative time of a controller	DQPSKDSL	differential quadrature phase shift keyingdigital subscriber line
DA	data access	DSP	digital signal processing
D/A	digital-to-analog	DSR	direct screen reference
DAC	device access code	DSSS	direct sequence spread spectrum
DACU	data acquisition and control unit	DT	dead time (second or minutes)
DAE	differential algebraic equation	DTC	digital temperature compensation
DAMPS	digital advanced mobile phone system	DTE	data terminal equipment
dB	decibels	DTGS	deuterated tryglycine sulfate
DBB	double-block and bleed	DTM	device type manager (An active-X compo-
DBPSK	differential binary phase shift keying		nent for configuring an industrial network
DC	diagnostic coverage		component. A DTM “plugs into” an FDT.)
DC, dc	direct current	DU	dangerous component failure occurred in
DCE	data communications equipment		leg, but undetected
DCOM	distributed COM	DVM	digital voltmeter
DCS	distributed control system
DD	data definition or dangerous component fail-		E
	ure is detected in leg or a device description	e	(1) error, (2) base of natural (Naperian)
	written using DDL		logarithm, (3) exponential function; also
D/DBP	disinfectants/disinfection byproducts		exp (-x) as in e-x
DDC	direct digital control	E	(1) electric potential in volts, (2) scientific
DDE	dynamic data exchange		notation as in 1.5E – 03 =  1.5 ´ 10-3
DDL	device  description  language  (an  object-	E{.}	expected value operator
	oriented data-modeling language currently	EAI	enterprise application integration
	supported by PROFIBUS, FF, and HART)	EAM	enterprise asset management
deg	degree; also ° (p/180 rad)	EBCDIC	extended binary code for information inter-
DES	data encryption standard		change
DFIR	diffused infrared	EBR	electronic batch records
DFR	digital fiber-optic refractometer	ECD	electron capture detector
DFT	digital Fourier transform	ECKO	eddy-current killed oscillator
DH	data highway	ECN	effective carbon number

ECTFE	ethylene chloro-tetra-fluoro-ethylene (Halar)	FCS	frame check sequence
EDS	electronic data sheet (DeviceNet)	FDE	fault disconnection electronics
EDTA	ethylenediaminetetraacetic acid	FDL	fieldbus data link
EDXRF	energy dispersive x-ray fluorescence	FDMA	frequency division multiple access
E/E/PE	electrical/electronic/programmable electronic	FDS	flame-detection system
E/E/PES	electrical/electronic/programmable electronic	FDT	field   device   tool   (a   Windows®-based
	system		Microsoft framework for engineering and
EFD	engineering flow diagram		configuration tools)
e.g.	exempli gratia (for example)	FE	final elements
EHC	electrohydraulic control	FEED	front end engineering and design
EHM	equipment health management	FEGT	furnace exit gas temperature
e(k)	feedback error	FEP	fluorinated ethylene propylene
E.L.	elastic limit	FES	fixed end system
Emf, EMF	(1) electromotive force (volts), (2) electro-	FF-HSE	Foundation Fieldbus, high-speed Ethernet
	motive potential (volts)	FFT	fast Fourier transform
EMI	electromagnetic interference	FH	frequency hopping
EMI/RFI	electromagnetic interference/radio frequency	Fhp	fractional horsepower (e.g., 1/4-hp motor)
	interference	FHSS	frequency hopped spread spectrum
em(k)	process/model error	FI	flow indicator
EN	European standard	FIA	flow injection analyzer
EPA	enhanced performance architecture, Envi-	FIC	flow indicator controller
	ronmental Protection Agency	FID	flame ionization detector
EPC	engineering-procurement-construction	FIE	flame ionization element
	(firm or industry)	FIFO	first-in, first-out
EPCM	engineering,  procurement,  and  construc-	Fig.	figure
	tion management (companies)	FISCO	fieldbus Intrinsic Safety COncept
EPDM	ethylene propylene diene terpolymer	fl.	fluid
EPS	electronic pressure scanner, Encapsulated	oz.	fluid ounce (= 29.57 cc)
	PostScript file or emergency power supply	FM	frequency modulated
EQ, eq	equation	FMCW	frequency modulated carrier wave
ERM	enterprise resource manufacturing	FMEA	failure mode and effects analysis
ERP	enterprise resource planning, effective radi-	FMEDA	failure modes, effects and diagnostic analysis
	ated power	FMS	fieldbus message specification or fieldbus
ERW	electric-resistance welded		messaging services/system
ESD	emergency  shutdown  (system),  electro-	FO	fiber optic or fail open
	static discharge	FOP	fiber-optic probe
ESN	electronic serial number	FOV	field of view
ETFE	ethylene-tetrafluoroethylene   copolymer	fp, f.p.	freezing point
	(Tefzel®)	FPC	fine particle content
ETS	equivalent time sampling	FPD	flame photometric detector
Exp	exponential function as in exp (– at) = e-at;	FPM, fpm,	feet per minute (= 0.3048 m/m)
	also e	ft/min
		fps, ft/s	feet per second (= 0.3048 m/s)
	F	FRCFRM	flow recording controllerfrequency response method
F	frequency (also freq.)	FS, fs	full scale
F	farad, symbol for derived SI unit of capac-	FSC	fail safe controller
	itance, ampere-second per volt, A·s/V	FSD	full scale deflection
°F	degrees Fahrenheit [t°C = (t°F – 32)/1.8]	FSK	frequency shift keying
FAT	factory acceptance testing	FT	Fourier transform
FBAP	function block application process (FF)	FTA	fault tree analysis
FBD	function block diagram	FTIR	Fourier transform infrared
FBG	fiber bragg grating	FTNIR	Fourier near infrared
FC	flow controllers	FTP	file transfer protocol
FCC	fluid catalytic cracking unit	FTS	fault-tolerant system
FCOR	filtering and correlation (method)	FTU	formazin turbidity unit

MVC MW	minimum variance controller megawatt (= 106 W)	OLE OLE_DB	object linking and embeddingobject linking and embedding data base
MWC	municipal waste combustors	OMMS	optical micrometer for micromachine
MWD	molecular weight distribution	ON	octane number
		OPC	object link embedding (OLE) for process
	N		control
N	Newton,  symbol  for  derived  SI  unit  of	OP-FRIR	open path Fourier-transform infrared
	force, kilogram-meter per second squared,	OP-HC	open-path hydrocarbon
	kg·m/s2	OP-TDLAS	open-path  tunable  diode-laser  absorption
n	(1) nano, prefix meaning 10-6, (2) refrac-		spectroscopy
	tive index	OP-UV	open-path ultraviolet
N0N-16	Avogadro’s number (= 6.023 ´ 1023 mol-1)nitrogen-16	orORP	orange (typical wiring code color)oxidation-reduction potential
NAAQS	national ambient air quality standards	OS	operator station or operating system
NAP	network access port/point	OSFP	open shortest path first
NAT	network address translation	OSI	open system interconnect (model)
NB	nominal bore, internal diameter of a pipe	OSI/RM	open system interconnect/reference model
	in inches	OT	operator terminal or open tubular
NC, N/C	normally closed (switch contact)	OTDR	optical time domain
NC	numeric controller	oz	ounce (= 0.0283 kg)
NDIR	nondispersive infrared
NDM	normal disconnect mode		P
NDT	nondestructive testing	P&ID	piping and instrumentation diagram
NEC	National Electrical Code	p	(1) pressure; (2) pico, prefix meaning 10-12
NESC	National Electrical Safety Code		(3) variable for resistivity
NEXT	near-end crosstalk	Pa	pascal, symbol for derived SI unit of stress
NIC	network interface card		and pressure, Newtons per square meter,
NIP	normal incident pyrheliometer		N/m2
NIR	near infrared	PA	plant air
nm	nanometer (10-9  m)	PAC	path average concentration
NMR	nuclear magnetic resonance	PAL	phase alternating line
NO, N/O	normally open (switch contact)	PAN	personal area network
NPS	nominal pipe size, the internal diameter of	P&ID	piping (process) and instrumentation dia-
	a pipe in inches		gram (drawing)
NRM	normal response mode	Pas, Pa·s	pascal-second, a viscosity unit
NRZ	non-return to zero (refers to a digital sig-	PAS	process automation system (successor to
	naling technique)		DCS)
NS	nominal pipe size, the internal diameter of	PB	proportional band of a controller in percent
	a pipe in inches		(100%/controller gain)
NTC	negative temperature coefficient	PC	personal   computer   (usually   Microsoft
NTP	network time protocol or normal tempera-		Windows®-based) or pressure controller
	ture and pressure corresponding to 1 atm	PCA	principal component analysis
	absolute (14.7 psia) and 0°C (32°F)	PCCS	personal computer control system
NTSC	National Television Standards Code	PCDD	polychlorinated dibenzo-p-dioxine
NTU	nephalometric turbidity unit	PCDF	polychlorinated dibenzo furans
NUT	network update time	PCR	principal component regression
		PCS	process control system or personal commu-
	O		nication services
OCD	orifice-capillary detector	pct	percent; also%
OD	outside diameter or oxygen demand	PCTFE	polychlorotrifluoroethylene
ODBC	open database connectivity or communica-	PCV	pressure control valve
	tion	PD	positive displacement or proportional and
OES	optical emission spectrometer		derivative
oft, OFT	optical fiber thermometry	PDA	personal  digital  assistant  or  photodiode
ohm	unit of electrical resistance; also W (omega)		array
OJT	on-the-job training	PDD	pulsed discharge detector

PDFPDS PDU PDVF PE PED PEEK PEL PES PFA	probability density function, probability of failure or portable document filephase difference sensor protocol data unit polyvinylidene fluoride polyethylenepressure equipment directive poly ether ether ketone permissible exposure level programmable electronic system per-fluoro-alkoxy copolymer	PRC PRD precip PRV PS PSAT PSDPSG PSIpsi, PSI, lb/in2	pressure recording controller pressure relief device precipitate or precipitated pressure relief valvepower supply (module)pre-startup acceptance testpower  spectral  density  or  photosensitive devicephosphosilicate glass pre-startup inspectionpounds per square inch (= 6.894 kPa)
PFC	procedure functional chart	PSIA, psia	absolute pressure in pounds per square inch
PFD	process flow diagram	PSID, psid	differential pressure in pounds per square
PdM	predictive maintenance		inch
pF	picofarad (= 10-12  F)	PSIG, psig	above  atmospheric  (gauge)  pressure  in
PF, p.f.	power factor		pounds per square inch
PFA	perfluoralkoxy (a form of Teflon)	PSK	phase shift keying
PFD	process flow diagram	PSM	process safety management
PFD	probability of failure on demand	PSSR	re-startup safety review
PFDavg	average probability of failure on demand	PSTN	public switched telephone network
PFPD	pulsed flame photometric detector	PSU	post-startup
PGNAA	prompt gamma neutron activation analysis	PSV	pressure safety valve
PGC	process gas chromatograph	pt	point, part, or pint (= 0.4732 liter)
pH	acidity  or  alkalinity  index  (logarithm  of	PTB	Physikalisch-Technische Bundesanstalt
	hydrogen ion concentration)	PTC	positive temperature coefficient
PHA	process hazard analysis	PTFE	polytetrafluoroethylene (conventional Teflon)
pi, pl	Poiseuille, a viscosity unit	PUVF	pulsed ultraviolet fluorescence
PI	proportional and integral, or pressure indi-	PV	process  variable  (measurement)  or  the
	cator		HART primary variable
P/I	pneumatic to current (conversion)	PVC	polyvinyl chloride
PIC	pressure indicating controller or path inte-	PVDF	polyvinylidene fluoride
	grated concentration	PVLO	process variable low (reading or measure-
PID	proportional, integral, and derivative (con-		ment)
	trol modes in a classic controller), or pho-	PVHI	process variable high (reading or measure-
	toionization detector		ment)
PI-MDC	path integrated minimum detectable con-	PWM	pulse width modulation
	centration	PWR	pressurized water reactor
PIMS	process information management system	PZT	lead-zirconate-titanate ceramic
PIPPIR	process industry practicesprecision infrared radiometer		Q
PLC	programmable logic controller	q	(1) rate of flow, (2) electric charge in cou-

R	(1) resistance, electrical, in ohms, (2) resis- tance, thermal, meter-Kelvin per watt, m·K/W, (3) gas constant (= 8.317 ´  107	RTOS RTR RTS	real-time operating system remote transmission request ready (or request) to send
	erg·mol-1,°C-1), (4) roentgen, symbol for	RTS/CTS	request to send/clear to send
	accepted unit of exposure to X and gamma	RTU	remote terminal unit
	radiation (= 2.58 ´ 10-4  C/kg)	RUDS	reflectance units of dirt shade
Ra	radium	RV	relief valve
rad	(1) radius, also r, (2) radian, symbol for SI	RWS	remote workstation
	unit of plane angle measurement or symbol
	for accepted SI unit of absorbed radiation		S
	dose (= 0.01 Gy)	s	second (also sec), symbol for basic SI unit
RADAR	radio detection and ranging		of time; also Laplace variable
RAID	redundant array of inexpensive disks	S	siemens (siemens/cm), symbol for unit of
RAM	random access memory		conductance, amperes per volt, A/V
R&D	research and development	s2y	sample variance of output y
RASCI	responsible for, approves, supports, con-	SAP	service access point
	sults, informed	sat.	saturated
RCU	remote control unit	SAT	site acceptance test or supervisory audio tone
RDP	remote desktop protocol	SAW	surface acoustic wave
rem	roentgen   equivalent   man   (measure   of	SC	system codes
	absorbed radiation dose by living tissue)	SCADA	supervisory control and data acquisition
rev	revolution, cycle	SCCM	standard cubic centimeter per minute
Re	Reynolds number	SCD	streaming current detector
ReD	Reynolds number corresponding to a par-	SCFH	standard cubic feet per hour
	ticular pipe diameter	SCCM	standard cubic centimeter per minute
RF, rf	radio frequency	SCD	sulfur chemilumenesce detector
RFC	request for comment (an Internet protocol	SCE	saturated calomel electrode
	specification)	SCFH	standard cubic feet per hour
RFF	remote fiber fluorimetry	SCFM	standard cubic feet per minute (air flow at
RFIRFQ	radio frequency interferencerequest for quote	SCM	1.0 atm and 70°F)station class mark
RGA	residual gas analyzer	SCMM	standard cubic meters per minute
RGB	red, green, blue	SCO	synchronous connection oriented
RGM	reactive gaseous mercury	SCOT	support coated open tubular (column)
RH	relative humidity	SCR	silicon-controlled rectifier
RI	refractive index	SCS	sample control system
RIP	routing information protocol	SD	component in leg has failed safe and failure
r(k)	set point		has been detected
RMS, rms	root mean square (square root of the mean	SDIU	Scanivalve digital interface unit
	of the square) or rotary mirror sleeves	SDN	send data with no acknowledgement
ROI	return on investment	SDS	smart distributed system
ROM	read-only memory	SEA	spokesman election algorithm
RON	research octane number	sec	second, also s
RPC	remote procedure call (RFC1831)	SER	sequence of event recorder
RPM, rpm,		SFC	sequential function chart
r/min	revolutions per minute	SFD	system  flow  diagram  or  start  of  frame
RVP	Reid vapor pressure		delimiter
rps, r/sec	revolutions per second	SFF	safe failure fraction
RRF	risk reduction factor	SFI	sight flow indicator
RRT	relative response time (the time required to	SFR	spurious failure rate
	remove most of the disturbance)	S.G.	specific gravity, also sp. gr.
RS	recommended standard	SHE	standard hydrogen electrode
RSA	rural service areas	SHS	sample handling system
RSS	root sum squared	SID	system identification digit (number)
RTD	resistance temperature detector	SIF	safety instrumented function
RTO	real-time optimization or operation	SIG	special interest group

SILsin	safety integrity levelsine, trigonometric function	T	T(1) ton (metric = 1000 kg), (2) time, (3)
SIS	safety instrumented system		thickness
SISO	single-input single output	T	(1) temperature, (2) tera, prefix meaning
SG, SpGSIL	specific gravity; also sp. gr.safety integrity level		10-12, (3) period (= 1/Hz, in seconds), (4)tesla, symbol for derived SI unit of mag-
SIS	safety instrumented system		netic flux density, webers per square meter,
SKU	stock keeping units		Wb/m2
SLAMS	state and local air monitoring stations	T1/2	half life
SLC	safety life cycle	tan	tangent, trigonometric function
slph	standard liters per hour	TAS	thallium arsenic selenide
slpmSMR	standard liters per minutespecialized mobile radio	tau, tTBM	process time constant (seconds)tertiary butyl mercaptan
SMTP	simple mail transfer (management) proto-	t/c	thermal coefficient of linear expansion
	col	TC	thermocouple,  temperature  controller,  or
S/N	signal-to-noise (ratio)		total carbon
SNG	synthetic natural gas	TCD	thermal conductivity detector
SNMP	simple network management protocol	TCP	transmission control protocol
SNR	signal-to-noise ratio	TCP/IP	transmission control protocol/internet pro-
SOAP	simple object access protocol (an Internet		tocol
	protocol that provides a reliable stream-	TCV	temperature control valve
	oriented connection for data transfer)	td	process dead time (seconds)
SOESONAR	sequence of eventssound navigation and ranging	Td	derivative time (in seconds) of a PID con- troller
SOP	standard operating procedure	TDLAS	tunable  diode  laser  absorption  spectros-
SP	set point		copy
SPC	statistical process control	TDM	time division multiplexing
SPDT	single-pole, double-pole throw (switch)	TDMA	time division multiple access
SPL	sound pressure level or sound power level	TDR	time domain reflectometry
SPRT	standard platinum resistance thermometer	T/E	thermoelectric
SPST	single-pole, single-throw (switch)	TEM	transmission electron microscope
sq	square, squared	TG	thermogravimetry
SQC	statistical quality control	Ti	integral time (in seconds) of a PID control-
SQL	structured (or standard) query language		ler
Sr	steradian, symbol for SI unit of solid angle	TI	time interval between proof tests (test inter-
	measurement		val), temperature indicator
SRD	send and request data with reply	TIC	temperature indicating controller or total
SRS	safety requirements specification		inorganic carbon
SRV	safety relief valve	TIFF	tagged image file format
SS	stainless steel	TISAB	total ionic strength adjustment buffer
SSL	secure socket layers	TLV	threshold limit value
SSU	Saybolt seconds universal	TMP	thermomechanical pulp
std.	standard	TMR	triple modular redundancy
ST	structural text	TN	total nitrogen
STEL	short-term exposure limit	TOC	total organic carbon
STEP	standard for the exchange of product model	TOD	total oxygen demand
	data	TOF	time of flight
STP	shielded twisted pair, or standard tempera-	TQM	total quality management
	ture and pressure, corresponding to 70°F	TOP	technical and office protocol
	(21.1°C) and 14.7 psia (1 atm abs)	TR	temperature recorder
STR	spurious trip rates	T/R	transmit/receive
SU	security unit or component in leg has failed	TRC	temperature recording controller
	safe and failure has not been detected	T.S.	tensile strength
SUS	Seybold universal seconds	TTFM	transit time flow measurement
SV	secondary variable or safety valve	TTP	through the probe
S/W	software	TV	tertiary variable

°TwTWA Twaddell degrees of liquid density time weighed average VLF V/M very low frequency voltmeter VME Virsa Module Europa (IEEE 1014–1987) U VMS vibration monitoring system uUART prefix = 10-6, used incorrectly when theGreek letter m is not availableuniversal asynchronous receiver transmit- VOCVR VRML volatile organic compoundsvirtual realityvirtual reality modeling language ter vs. versus UBET unbiased estimation UCMM unconnected message manager W UDP user/universal  data  protocol  (an  Internet w (1) width, (2) mass flow rate protocol with low overhead but no guaran- W (1)  watt,  symbol  for  derived  SI  unit  of tee that communication was successful) power, joules per second, J/s, (2) weight UEL upper explosive limit (also wt) ufb(k) feedback controller output w. water UFD utility flow diagram WAN wide area network uff(k) feedforward controller output Wb weber, symbol for derived SI unit of mag- UHF ultra-high frequency netic flux, volt-seconds, V·s UHSDS ultra-high-speed deluge system WCOT wall coated open tubular (column) u(k) controller output WDXRF wavelength dispersion x-ray fluorescence UML universal modeling language WG standard (British) wire gauge UPS uninterruptible power supply wh white (wiring code color for AC neutral UPV unfired pressure vessel conductor) URL upper range limit WI Wobbe index URV upper range value WLAN wireless local area network USB universal serial bus WPAN wireless personal area network UTP unshielded twisted pair WS workstation UTS ultimate tensile stress wt weight, also W UUP unshielded untwisted pair UV ultraviolet X UV-VIS-NIR ultraviolet-visible-near infrared X reactance in ohms XML extensible markup language V x-ray electromagnetic  radiation  with  a  wave- v velocity length <100 Å V volt, symbol for derived SI units of voltage, XRF x-ray fluorescence electric potential difference and electromo- XYZ tristimulus functions Vac                      voltage, alternating current V&V                   verification and validation VBA                    Visual Basic for Applications VDF                    vacuum fluorescent display VDT                    video display tube VDU                    video display unit vert.                     vertical VFD                    variable frequency drive VFIR                   very fast infrared VHF                    very high frequency VIS                      visible V-L                      vapor-liquid (ratio) Y Y/; expansion factor y(k)  process output yd:yard (= 0.914 m) yr: year Z Z :(1) atomic number (proton number), (2) electrical impedance (complex), expressed in ohms ZEB :zero energy band

Tags:ACRONYMS, AND SYMBOLS, CONTROL SYSTEMS ABBREVIATIONS, DCS ABBREVIATIONS, INSTRUMENTATION ABBREVIATIONS, INSTRUMENTATION DEFINITIONS, INSTRUMENTATION SYMBOLS DEFINITION, NOMENCLATURE, PLC ABBREVIATIONS, RTU ABBREVIATIONS, SCADA ABBREVIATIONS