Keithley 7057A User manual

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KEITHLEY
INSTRUMENTS
Model 7057A
Thermocouple Scanner Card
Instruction Manual
Contains Operating and Servicing Information
Publication Date: January 1992
Document Number: 7057A-901-01 Rev. D

WARRANTY
Keithley Instruments, Inc. warrants this product to be free from defects in material 11nd workmanship for a
period of 1 year from date of shipment.
Keithley Instruments, Inc. warrant8 the following items for90 days from the date ofshipment: probes,cables,
rechargeable batteries, diskettes, and documentation.
During the warranty period, we will, at our option, either repair or replace any product that proves to be de-
fective.
To exercisethis warranty, write or call your local Keithleyrepresentative, or contactKeithley headquarters in
Cleveland,Ohio. You will be given prompt assistance and return instructions. Send the product, transporta-
tion prepaid, to the indicated service facility. Repairs will be made and the product returned, transportation
prepaid. Repaired or replaced products are warranted for the balance of the original warranty period, or at
least 90 days.
LIMITATION OF WARRANTY
This warranty does not apply to defectsresultingfrom product modification without Keithley'sexpresswrit-
ten consent, or misuse of any product or part. This warranty also does not apply to fuses, software, non-re-
chargeablebatteries, damage from battery leakage, or problems arisingfrom normal wear or failure to follow
instructions.
THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING
ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. THE
REMEDIES PROVIDED HEREIN AREBUYER'S SOLE AND EXCLUSIVE REMEDIES.
NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR
ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT
OF THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS
BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAM-
AGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTS OF REMOVAL AND INSTALLATION,
LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON, OR DAMAGE TO PROPERTY.
KEITHLEY
INSTRUMENTS
Instruments Division, Keithley Instruments, Inc.• 28775 Aurora Road• Cleveland, Ohio44139 • (216) 24/l-0100 • Fax: [phone]B
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Safety Precautions
The following safety precautions should be obse1ved before using this product and any asso-
ciated instrumentation. Although some instruments and accessories would normally be used
with non-hazardous voltages, there arc situations where hazardous conditions may be present.
This product is intended for use by qualified personnel who recognize shock hazards and are
familiar with the safety precautions required to avoid possible injury. Read the operating in-
fonnation carefully before using the product.
The lypcs of product users are;
Responsible body is the individual or group responsible for the use and mainlenance of
equipment, for ensuring that the equipment is operated within lls specifications and operat-
ing limits, and for ensuring that operators are adequately trained.
Operators use the product for its intended function. They must be trained in electrical safety
procedures and proper use ofthe instrument. They must be protected from electric shock and
contact with hazardous live circuits.
Maintenance personnel perform routine pro.ccdurcs on the product to keep it operating, for
example, setting the line voltage orreplacing consumable materials. Maintenance procedures
arc described in !he manual.111e procedures explicitly state if the operator may perform them.
Otherwise, they should be performed only by service personnel.
Service personnel arc trained to work on live circuits, and perform safe installations and re-
pairs of products. Only properly trained service personnel may perfonn installation and ser-
vice procedures.
Exercise extreme caution when a shock hazard is present. Lclhal voltage may be present on
cable connector jacks or test fixtures. 111c American National Standards Institute (ANSI)
states that a shock hazard exists when voltage levels greater than 30V RMS, 42.4V peak, or
60VDC are present. A good safety practice Is to expect that hazardous voltage is prtscnt
in an)' unknown circuit before measuring.
Users of this product must be protected from electric shock at all times. 11re responsible body
must ensurethatusers arepreventedaccess and/orinsulalcd from everyconnectionpoint. In some
cases. connections must be exposed to potential human contact. Product users in these circum-
stances must be trained to protect themselves from the risk of electric shock. Ifthe circuit is ca-
pable of operating at or above l 000 volts, no conductive part of the circuit may be exposed.
As described in tile International Eloctrotechnical Commission (IEC) Standard !EC664, dig-
ital multimeter measuring drcuits (e.g., Keithley Modcis 175A, 199, 2000, 2001, 2002, and
2010} are Installation Category IL AH other instruments' signal tenninals are Installation Cat-
egory I and must not be connected to mains,
Do not connect switching cards directly to unlimited power circuits. They are intended to be
used with impedance limited sources. NEVER connect switching cards directly to AC mains.
When connecting sources to switching cards, install protective devices to Jimit fault current
and voltage to lhc card.
Before operating an instrument, make sure the line cord is connected to a property grounded
power receptacle, Inspect the connecting cables, test leads, and jumpers for possible wear.
cracks, or breaks before each use.
For maximum safety, do not touch lhe product, lest cables, or any other instruments while pow-
er is applied to the circuit under test ALWAYS remove power from the entire test system and
discharge any capacitors before: connecting or disconnecting cables or jumpers, instaning or

removing switching cards, or making internal changes, such as installing or removing jumpers,
Do not touch any object that could provide a current path to the common side of the circuit
under test or power line (eatth) ground, Always make measurements with dry hands while
standing on a dry, insulated surface capable of withstanding the voltage being measured.
The instrument and accessories must be used in accordance with its specifications and op-
erating instructions or the safety of the equipment may be impaired.
Do not exceed the maximum signal levels of the instmments and accessories, .as defined in
the specifications and operating infonnation, and as shown on the instrument or test fixture
panels, or switching carcl.
When fuses are used in a product, replace with same type and rating for continued protection
against fire hazard.
Chassis connections must only be used as shield connections for measuring circuits, Nar as
safety earth ground connections.
If you are using a test fixture, keep the lid closed while power is applied to the device under
test. Safe operation requires the use of a lid interlock.
lf a @screw is present, connect it to safety earth ground using the wire recommended in
the user documentation.
TI1e .&symbol on an instrument indicates that the user should refer to the operating in-
structions located in the manual.
The&, symbol on an instrnment shows that it cm1 source or measure 1000 volts or more, in-
cluding the combined effect ofnonnal m1d common mode voltages. Use stm1dard safety precau-
tions to avoid personal contact with these voltages.
TI1c WARNING heading in a manual explains dangers that might result in personal injury or
death. Always read the associated infonnation very carefully before performing the indicated
procedure.
The CAUTION heading in a manual explains hazard'! that could damage the instrument.
Such damage may invalidate the warranty.
lnstn.nnentatiou and accessories shall not be connected to humans.
Before performing any maintenance, disconnect the line cord and all test cables.
To maintain protection from electric shock and fire, replacement components in mains cir-
cuits, including the power transfonner, test leads, and input jacks, must be purchased from
Keithley Instruments. Standard fuses, with applicable national safety approvals, may be used
if the rating and type are the same. Other components that are not safety related may be pur-
chased from other suppliers as long as they are equivalent to the 01iginal component. (Note
that selected parts should be purchased only through Keithley Instruments to maintain accu-
racy and functiona1ity of the product.) 1f you are unsure about the applicability of a replace-
ment component, call a Keithley Instruments office for infonnation.
To clean an instrument, use a damp cloth or mild, water based cleaner. Clean the exterior
of the instrument only. Do not apply cleaner directly t6 the instrument or allow liquids to
enteror spill on the instrument. Products that consist of a circuit board with no case or chas-
sis (e.g., data acquisition board for installation into acomputer) should never require clean-
ing ifhandled according to instructions, If the board becomes contaminated and operation
is affected, the board should be returned to the factory for proper cleaning/servicing.
Rev. 2/99

SPECIFICATIONS
CHANNELS PER CARD: 9 plus temperature reference.
CONTACT CONFIGURATION: 2 Pole Form A with common guard.
CONNECTOR TYPE: Screw terminals in isothermal block, No. 18 AWG wire
maximum.
RELAY DRIVE CURRENT: 12mA (per relay).
TEMPERATURE OFFSET: ±0,05°C maximum from HI to LO of any input or be-
tween any two adjacent channels in one column on the isothermal block. ± 0.1 °C
maximum between any two terminals on the isothermal block. Maximum addi-
tional dynamic offset due to 10°C step change in environment: ± 0.1 °C after one
hour settling.
TEMPERATURE REFERENCE: Thermistor in a linearized bridge.
REFERENCE OUTPUT: -1 mV/
0
c, (OmV at +30°C).
REFERENCE ACCURACY: ±0.26°C 110°c to 35°C), ±0.5°C
{0°C to 10°c and 35°C to 60°C).
WARM UP TIME: 1 Hour to rated accuracy.
CONTACT OFFSET VOLTAGE: 1µV.
ACTUATION TIME: < 5ms, exclusive of mainframe.
CONTACT LIFE: > 10
8 closures,
CONTACT RESISTANCE:< 20 I <0.70 initial).
CHANNEL ISOLATION: > 10
80, 10pF.
INPUT ISOLATION: > 10
70, 150pF.
COMMON MODE VOLTAGE: 200V peak.
ENVIRONMENT, SPECIFIED: 10°C to 35°C, up to 70% R.H.
ENVIRONMENTAL, OPERATING: o•c to 50°C, up to 35°C at 70% R.H.
ENVIRONMENTAL, STORAGE: -25°C to +65°C.
DIMENSIONS, WEIGHT: 32mm high x 114mm wide x 272mm long (1 ¼" x
4½"x 10¾") netweight0.64kg (lib. 6.5oz.).
Signal Level: 42V, 100mA, 2VA maximum (non-inductive load only),

TABLE OF CONTENTS
SECTION 1-GENERAL INFORMATION
1.1 Introduction . . . . .. .. . . . . .. . . . . . . . . . . . . . .... . . . . .. .. . . . . . . 1
1.2 Warranty Information . . . . . . . . . . . . . . . .. . . .. . . . . . . . . .. . . . . . . 1
1.3 Manual Addenda......................................... 1
1.4 SafetySymbolsandTerms .... ..... ... .. .. ... .. .. ... .. .. .. 1
SECTION 2-OPERATION
2. 1 Introduction .. .. .. .. .. .. .... .. .. . .. . . . . .... . .. .. . . . . .. . . 3
2.2 Wiring . . . . . . . . . .. . . . . . . . .. . . . . . . .. .. . . . . . . . . . .. . .. .. . . . . 3
2.3 Operating Considerations .. .... . . . .. . . . . . . .... . . . .. . .... . . . 4
2.4 Operating Hints . .. . .. . . .. .... . . . . .. . . . . .. . .. .. .. . .. . . . . . . 4
2.5 Thermocouple Measurement Considerations . . . . . . . . . . . . .. . . . . 5
26 Measurement Procedure . . . . . . . . . . . . .. . . . .... . . . . . . . . . . . .. 6
2.7 Switch Terminology...................................... 7
SECTION 3-SERVICING INFORMATION
3. 1 Calibration Procedure .. .. . .. . . . . . . .. . . . . .. . . . . . . .. .... . . . . 21
3.2 Calibration Procedures . . . . .. . . . . . .. . .. . .... .. .. . . . . .. . . . .. 21
3.3 Test of Calibration .. . . . . . . .. . . . . . .. . .. . .. . .. . . . . . . . . . . . . . . 21
3.4 Channel Isolation. . . . . . . . .... . . . . . .... . . . .. . . . . . . .. . . .. .. . 21
3.5 Input Isolation, Common Mode.. . . . . .. . . . . .. . . . . . . . .. . . . . . . 22
SECTION 4-REPLACEABLE PARTS
4.1 Introduction . . . .. .. . . . . . .. .. . . . . . .. . . . .. . . .. . . . . . . . . . . . . . 23
4.2 Replaceable Parts . .. . . . . .. . . . . .. . . .. . . . . . .. . . . . . . .. . . . . .. 23
4.3 Ordering Information .. .. .. . . . .. .. . . .. .. .. .. . .. .. .. . .. .. . . 23
4.4 Factory Seivice . . .. . . . . .. . .. . . .. .. . . . . . . . . . . . .. .. . .... . . . 23
4.5 Component Layout and Schematic Diagram . . . . . . . . . . . . . . . . . . 23
LIST OF FIGURES
1 Typical Thermocouple Connections . . .. . . .. .. .. . .. . .. . . . . . . . 3
2 Plug-In Board Assembly . .. . . . . . . .. . .. . . . .... . . . . . .. . . . . .. . 4
3 Using GUARD Connection.. . .. .. . . . . . . . . . . .. . . . . . .. . . . . . .. 5
4 Typical Multiple Channel Analog Connections . . . . . . . . . . . . . . . . . 5
5 Typical Thermocouple Measurements . . . . . . . . . . . . . . . . . . . . . . . 6
6 SwitchTerminology .. . . .... . . . . . .. . . . . .. . . . . . . . . . . . .. . . . . 7
7 Channel'lsolation Test Setup . . . . . . .. . . . . . . .. . . . . .. . .. .. . . . . 22
8 Common Mode Isolation Test Setup . . . . . . . .. . . . . .. . .. . . . . . . 22
9 Model 7057A, Component Location Drawing....... . . . . . . . . . . 26
10 Model 7057A, Schematic Diagram .. . . . . . .. . . . . . . . . . . .. . . . . . 27
LIST OF TABLES
1 SummaryofTemperatureMeasurementProcedure... ... . . . . 7
2 NBS QuarticCoefficientsforTypesS, A, B, E,J, KandT....... 8
3 Recommended Test Equipment. . . .. . .. . . . .. .. . . . .. . . .. . .. . . 21
4 Model 7057A Replaceable Parts .... .. . . . . . .... . . . . . .. . . . .. . 23
5 Model 7057A Replaceable Parts (Mechanical)............. . . . . 24

SECTION 1
GENERAL INFORMATION
1.1 INTRODUCTION
The Model 7057A is a thermocouple scanner card which isfield-installable in an
appropriate scanner mainframe (e.g. Model 705). Since it combines the func-
tions of a thennocouple scanner and uniform temperature reference, it is
especially useful for scanning thennocouples. The input terminals are #110 alloy-
copper set in an isothermal block to minimize temperature differences. A ther-
mistor sensor within the isothermal block is used with a bridge network located
on the Model 7057A to give an indication of the temperature reference or cold
junction. The temperature of the heat sink is used to calculate the corrected
thennocoup!e output. The output voltages of each thermocouple must be con-
verted to temperature (°C or °F) using appropriate thermocouple tables or
polynomial equations. In addition any channel may be used for monitoring low-
level signals. The Model 7057A uses 2-pole form A contacts for switching of
signals up to 35V peak or 100mApeak. Inputand output connections are msde
through the rearpanel of the scanner mainframeusing #4 screwterminalson the
Model 7057 A.
1.2 WARRANTY INFORMATION
Warranty information is stated on the inside front cover of the manual. If there is
a need for service, contact the Keithley representative or authorized repair facility
in your area. Check the back cover of this manual for addresses. The service
farm supplied at the end of this manual should be used to provide the repair
facility with adequate information concerning any difficulty.
1.3 MANUAL ADDENDA
Any improvements or changes to this manual will be explained on an addendum
included with this manual.
1.4 SAFETY SYMBOLS AND TERMS
The symbol &, denotes that the user should refer to the operating instrucM
tions.
The symbol #denotes that a high voltage may be present on the ter-
minal!s).
The WARNING used in this manual explains dangers that could result in
personal injury or death.
The CAUTION used in this manual explains hazards that could damage the
instrument.
1

2.1 INTRODUCTION
SECTION 2
OPERATION
This section provides information needed to use the Model 7057A with an
appropriate scanner mainframe.
2.2 WIRING AND INSTALLATION
1. Wiring Configuration- The Model 7057A has a 2-pole switching configura-
tion. It may be used to connect one of nine signals to the output. The tenth
scanner position {Channel 1) is used to monitor the temperature of the input
terminals with a thermistor bridge. Bridge power is derived from a non-
isolated internal supplywith jumper provisionsfor an external isolated supply.
A. Input and output connections are made to the screw terminals shown in
Figure 1.
B. Signal path resistance, including both poles of a channel relay, is typically
less than 1.40, less than 21l at end of life.
C. A guard surrounds all signal paths and is connected to the heat sink
surrounding the input terminals. Connection to the guard is made at the
isothermal block.
2. Installation-Refer to the scanner mainframe instruction manual for scanner
card installation instructions. ' I
DODOO
DODOO
'!@ @I
1, ® ® ® ®' @,. I
.· i i i 1= ! ~
• @)@)@@)®•
; @
: I! ® ® ® ®· • I
: ®l@i®i@l 8@• i i
!@ @~'
"-------------------'I
• © ®
Agure 1. Typical Thermocouple Conn&etions.
3

2.3 OPERATING CONSIDERATIONS
1. Signal Level-10V peak, 10mA peak with a resistive load tor expected lite.
Maximum peak instantaneous rating is 35V.
2. Contact Potential (Laboratory Environment)-Less than lµV from input to
output when copper wires are used.
3. Isolation-Guarded interchannel resitance is nominally 10Sn. Guarded capa-
citance is less than 100pF between any two channels.
4. Maximum Levels-A 200V peak between channels or from channel to
guard or mainframe (digital) common.
5. Operating Environment-0°C-50°C, up to 35°C at 70% relative humidity.
2.4 OPERATING HINTS
1. The clamp-type screw terminals will accept #18 to #36 AWG \0.044 to
0.005 inch) wire. Figure 2 shows the mechanical features of the Model
7057A which prevent lead movement after the board is wired.
REINSTALL
RUBBER PADS
AFTER HOOKUPS
TO BOARD
I
I I
I
'
I
Figure 2. Plug-In Board Assembly
2. Thermal offset on any given channel is typically repeatable to within a few
hundred nanovolts each time the channel is selected. That is, every time a
channel is selected and allowed to stabilize for a period of time, the channel
will exhibit the same thermal offset to within a few hundred nanovolts. This
offset may be accounted for in the measurement and subtracted from each
reading, to obtain a more precise measurement.
3. To effecf1vely eliminate error voltages produced by leakage current, the
GUARD terminal should be connected to the reference connection on the
channel which is most sensitive to error (that is, the one which has the
lowest source voltage versus the highest resistance). For instance, two
sources are connected to the Model 7057 A; one having an equivalent
source voltage of 1V with a series resistance of 100k0, and the other having
a source voltage of .1V with a 1k0 series resistance. The 100k0 source
resistance will develop 100 times the error voltage as the 1k0 source
resistance. lts source voltage however, is only 10 times as great, which
means that the percentage error is 10 times as large on the 1V/100k0 chan-
4

nel. The GUARD would therefore be connected to the reference point of
this channel. (See Figure 3). OUTPUT
HI
LO
GUARD
GUARD
l 1k0
~I
/
¥.4v
.,v =
T
>o
' /
'
>GUARD+
I
I
'
Figure 3. Using GUARD Connection
4. The relay switching time includes a 50µs time interval between releases and
operate conditions. The actuation time is less than 5msec.
5. Reactances in the system cause transients during switching_.
6. For scanner systems using two or more plug-in boards output HI and LO on
all Model 7057A plug-in boards should be made using continuous copper
wires. This ensures that the number of copper-to-copper junctions is at a
minimum and therefore unnecessary thermal effects are avoided. Figure 4
shows the method of continuous board-to-board connections.
ANALOG
SIGNAL
HI
MODEL MODEL MODEL OUTPUT
I _,ii: I ~i I: I -~I: ro :"
LO
FROM THERMOCOUPLE
OR OTHER SOURCE ALLOW SUFFICIENT SLACK
IN WIRE TO PERMIT
INSTALLATION AND
REMOVAL FROM
MAIN FRAME
Figure 4. Typical Multiple-Channel Analog Connections
2.5 THERMOCOUPLE MEASUREMENT CONSIDERATIONS
A thermocouple is a junction formed between two dissimilar metals. If the
junction temperature is T1 a voltage E1 will be developed between leads A and
B. When connected to a voltmeter two more junctions are formed with meter
terminals, which are usually copper as shown in Figure 5.
6

A
T1
B
THERDMDCOUPLE
JUNCTION
ISOTHERMAL BLOCK
'1 -TERMINAL - 7
I COPPER
"'-'
E2
: t
T2
I
I COPPER
I TERMINAL :
L-------
C
D
Figure 6. Typical Thermocouple Measurement
The voltage measured by the voltmeter is proportional to the difference be-
tween temperature T1 and T2• To determine T1, T2 the thermoelectric proper-
ties of the thermocoupleare needed. Data is available to determine the voltage
versus temperature relationship based on a reference temperature (T
2)
of 0°C.
Thus, if the thermocouple-to-copper junctions were maintained at oo-c it
would be possible to determine T1 directly by referring to thermocouple
reference tables*, which give temperature as a function of the meter reading
V1• If these junctions are different from 0°C a voltage E2 will be introduced,
where V, -E1 -E,.
2.6 MEASUREMENT PROCEDURE
In the Model 7057A the reference temperature Tis measured by a dual ther-
mistor in a bridge circuit. The temperature of a thermocouple connected to
Channels 2 through 10 is detennined by the following procedure:
1. Measure the voltage for the reference junction V and calculate T2• T2 =
30- IV, x 103).
2. Determine the reference junction voltage, E2, either from thermocouple
reference tables* or by the calculation**:
"2= "o+ A1 T + 11ir2+a3T3 +a
4r4 where T - T2
as detennined in step 1
above. ~ is expressed in microvolts. The constant ap through a4 are a
function of the thermocouple type connected to the channel. The coeffi-
cients, a0, a1, a2, 8s and a4 are dependent on the thermocouple type and
temperature range under consideration.
3. Measure the thermocouple voltage V, at the channel output. Convert to
microvolts.
4. Add ~ to V, to determine E~. E1 =V
1
+~ {where V1 1s expressed in
microvolts).
5. Determfne the thermocouple temperature, T1, either from thermocouple
reference tables* or by calculation**:
T, = 8o + a1E1, + a2E12t +~E,3 + a4E,
41{where E1is expressed in microvolts).
6. For example, consider a type J iron-constantan thermocouple at 300°C
(T
1
). The reference junction temperature will be 8 to 10°C above ambient,
say 3s
0c
!T,1.
6
A. The bridge output (channel 11 will be -.OOOV. Since the bridge output is
zero when T, = 30°C this indicates T2 = 3B°C.
B. Using NBS Monograph 125 to determine the referencevoltage for atype
J thermocouple gives E, =1849.0µV. Using the most accurate quartic
approximation formula (Table 2) for this range gives 1849.085,,V.
C. The voltage at Channel 1, which is V1, will be 14476.0µV. (V
1-E1
-E,).
D. Add E, to V1 and get E1 = 16325.0µV.

E. Using Table A6.2.1 to find the thermocouple temperature gives
300.00°C. Using the formula (Table 21 gives 299.995°C.
* Thermocouple Reference Tables, Based on the IPTS-68 National Bureau
Standards Monograph 125. (SD Catalog No. C13.44:125I
** See also Table 2 which summarizes the quartic coefficients.
Table 1. Summary of Temperature Measurement Procedure
Measured Calculated
Action
Quantity Relationship Required
Quantity
Measured reference ½
-- --
channel output V2• (volts)
Determine equivalent
--
T, = 30-(V, X 103)
T, (°C)
temperature T2•
Measured desired v,
--
--
channel V1, (volts)
Calculate corrSction
--
~ = a0 + a,T2 + a1 T2
2 +
E,
voltage E,
83 T32 + a4 T4
2 microvolts
Calculate voltage E1•
--
E, = E2 + v, X 10-6
E,
microvolts
Calculate equivalent
--
T, = a0 + a1E1 + a2 E2
1 + T1 (°CI
temperature T,. 8
381 + 84E41
2.7 SWITCH TERMINOLOGY
Throughout this manual the terminology Form A is used. The term Form A is
used in switch terminology and is described as follows:
1. Form A is simply a single pole normally open (SPNOJ switch (refer to
Figure 6). A 2-pole switch normally open is classified as 2 Form A.
2. Form 8 is similar to Form A except that its contacts are normally closed
(refer to Figure 61. A 2-pole switch normally closed is classified as a 2 Form
B.
3. Form C is shown in Figure 6 as a single pole double throw switch. It could
also be a multipole switch such as a 2-pole which would be classified as a2
Form C.
FORM A ___/"' 0--
ISPNOI
FORM B --.Q:--
(SPNC)
FORM C
ISPDT)
___.9-
0--
Figure 6. Switch Terminology
7

co
Type S Thermocouples'
Temperature
Range(°C)
-·---
I. Quartic Equation
-50 to 900
Oto 1100
0 to 1400
0 to 1650
0 to 1768
400 to 1100
400 to 1400
400 to 1650
1050 to 1400
1050 to 1650
1400 to 1550
1400 to 1650
1400 to 1768
1666 to 1768
Reference Junction
Correction
a to 50
Table 2. NBS Quartic Coefficients for Types S, R, B, E, J, K, and T.
•o
•1
a3
--·---
Argument
Exp. Argument Exp. · Argument
Exp.
Argument Exp.
Argument
-5.5439639
+O 1.0103667
-2-
--
-1.0944499 -5
4.9628963
5.8791282
+0
7.9098118 -3 -6.7450002
-6
2.5247577
6.2516859 +O
i 5.8347856
-3
-3.4351369 -6
9.4022202
6.5554932 +O 4.4519908 -3
-1.6378513 -6
2.4140360
6.6834421 +O 3.9334084 -3
-1.0384046 -6
3.4244511
-3.8051591 +2 8.7228147
+0
6.2984807 -4 9.0526670
-7
-2.9241601
-5.2412524 +2 9.5827994
+0
-1.2077351 -3 2.5723104
-6
-8.3681057
-5.0061921 +2 9.4591354
+O
-9.7986687
-4
2.3967559
-6
-7.8837971
1.4352322
+3 2.9873073
+0
6.9951678 -3 -1.8986036
-6
6.5006637
1.3054176
+3 3.4129348
+0
6.4741403 -3 -1.6163524
-6
7.9103746
1.8695098 +2 6.4091373 +O 3.4664812 -3
-2.7553724
-7
-2.1606150
1.0863331 +3 3.9952876 +O 5.8939317 -3
-1.3595782 -6 -3.4675031
-7.4180405 +4
2.0043202 +2
-1.8607781 -1 8.1899566 -5 -1.3556030
8.2703440
+4 -1.3532278
+2 8.0243878
-2 -1.0633404 -5 -1.7212343
5.3994446 +O
l 1.2467754
-2
-1.9934168 -5
Exp.
-9
-9
-10
-10
-11
-10
-10
-10
-11
-12
-10
-11
-8
-9
Error
Range(µVJ
-
Ex-"lct-Approx.
- 7 to 14
-16to12
-35 to 25
-55to35
-60 to 35
-.7to.5
- 1.6 to 1.5
-1.8 to 1.9
-.05 to .05
- .05 to .05
-.05 to
.05
-.05 to .05
-1.0tol.3
- .05 to .05
-0.01 to + 0.01
1
0uadratic, cubic, and quartic approximations to the data as a function of temperature (°C) in selected temperature ranges. The expansion is of the form
E =ao +a1T + a2T2+ a3T3 + a4T4 where E is in microvolts and T is in degrees Celsius.

"'
Type S Thermocouples"
Temperature
Range (°C)
I. Quartic Equation
-50 to 900
Oto1100
0 to 1400
0 to 1650
0 to 1768
400 to 1100
400 to 1400
400 to 1650
1050 to 1400
1050 to 1650
1400 to 1550
1400 to 1650
1400 to 1768
1666 to 1768
•o
Argument
Exp.
4.1137317 +1
4.4507790 +1
4.1670535
+1
-3.0938374
+1
1.=6607
+1
1.3866867 +2
1.3923740 +2
4.5133695 +3
2.3131446 +4
.,
Argument Exp. Argument
1.6414048
-1
-2.0241757
1.5445376 -1 -1.3349067
1.4713897
-1
-9.0783455
1.4260554
-1
-7.0073775
1.4087955
-1
-6.3195007
1.1599785 -1 -1.8642979
1.1373998
-1 -1.3349811
1.1543358
-1
-1.6782780
1.4106580
-1
-4.9794442
1.2706383
-1
-3.2873314
9.3486676 -2 4.8592708
9.3267401 -2 7.7266682
-1.0046437 +0 1.0322002
-5.4122671
+O 4.9347196
Exp. Argument Exp.
-5
2.7849728 -9
-5
1.3626587 -9
-6
6.5660913
-10
-6 3.8981279
-10
-6
3.1267454
-10
-6 1.2643267
-11
-6
-3.9224680
-11
-6 -1.0845801 -11
-6
1.7334256
-10
-6
8.3038098 -
11
-8
-6.3885209
-11
-8
-6.5458208
-11
-4 -4.3637046 -9
-4 -1.9681943 -8
Argument Exp.
-1.4172102
-13
-5.3270847
-14
-1.8499175
-14
-8.3047780 -15
-5.7422562 -15
8.4828836
-16
2.6563405
-15
1.8379726
-15
-1.9262160
-15
-1.3019379
-16
2.2896541
-15
2.3208160
-15
6.9361610
-14
2.9430179
-13
Error
Range (µVJ
Exact-Approx.
-11 to 3
-3 to 6
-5 to 9
-- 6 to l l
- 6 to 12
-.05 to .07
-.08 to .08
-.2 to .2
-.003 to .003
-010 to Olli
-0005 to 0005
-0005 to 0005
-13to10
-0005 to C,005
'Quadratic, cubic, and quartic approximations to the data as a function of voltage in selected temperature ranges (°C). The expansion is of the form
T=ao+a1E+a2E2+a3E3+a4E
4 where
Eis in microvolts and Tis in degrees Celsius.

Type A Thermocouples>
Temperature
Range (°CJ
I.
Quartic Equation
-50 to 900
Oto1100
0 to 1400
0 to 1650
Oto 1768
400 to 1100
400 to 1400
400 to 1650
1050 to 1400
1050 to 1650
1400 to 1550
1400 to 1650
1400 to 1768
1666 to 1768
Reference Junction
Correction
0 to 50
•o
Argument Exp.
-4.0674108
+2
-5.6047484 +2
-5.4505828 +2
1.6618159
+3
1.5132838 +3
2.4008703
+3
1.5787334 +3
-7.1904948 +4
8.8532076 +4
5.2891411 +O
•1
Argument Exp. Argument
5.4295008 +O 1.1446885
5.7622558
+O
9.2715271
6.1429m
+O
7.1515857
6.4615269
+O
5.7010917
6.5962120
+O
5.1559203
8.7490294
+O
1.7115155
9.6731111 +O
-2.6994046
9.5942872
+O
-1.2813352
2.3048526
+O
8.7635426
2.7958847
+O
8.1571403
4.1604579 -1 1.0549178
2.6321144
+O
8.3100314
1.9442383
+2
-1.7913090
-1.5014129
+2
9.5376167
1.3844426
-2
-2.0889531
a3
Exp. Argument
Exp.
-2
-1.1295306 -5
-3 -7.1346883 -6
-3 -3.7539447 -6
-3
-1.8683292
-6
-3
-1.2385309 -6
-3
7.5039035
-7
-4
2.5536988
-6
-4
2.4468512 -6
-3 -2.3016819 -6
-3
-1.9701159 -6
-2
-3.0383521 -6
-3 -2.0332036 -6
-1
7.9264764 -5
-2
-1.6644901 -5
-5 - 0.01 to + 0.01
Argument Exp.
5.0020496
-9
2.5877458 -9
9.6963832 -10
2.3636365
-10
1.8827643 -11
-3.0096280
-10
-8.9155491 -10
-8.6286756 -10
7.4284923 -11
6.5568964 -12
1.8540516 -10
1.6260416 -11
-1.3187245 -8
-8.3062870 -10
i
Error
Range {µV)
Exact-Approx.
- 7 to 15
-16to12
-35to25
-55 to 35
-65to35
-.4 to .5
-1.7101.6
-2.1to1.8
-.05 to .05
-.05 to .05
-.05 to .05
-.05 to .05
-1.0 to 1.3
-.05 to .05
>Quadratic, cubic, and quartic approximations to the data as a function of temperature {°C) in selected temperature ranges. The expansion is of the form
E=ao + a1T + a2T2 + a3T3+ a4T4 where Eis in microvolts and Tis in degrees Celsius.

..
..
Type R Thermocouples4
Temperature
Range (°C)
I. Quartic Equation
-50 to 900
0 to 1100
0 to 1400
Oto 1650
Oto 1768
400 to 1100
400 to 1400
400 to 1650
1050 to 1400
1050 to 1650
1400 to 1550
1400 to 1650
1400 to 1768
1666 to 1768
•o
Argument Exp.
4.5509556 +1
4.9160016 +1
4.8343651 +1
-4.1134459
+o
3.7487318
+1
8.0559850
+1
1.4180146
+3
3.1759093
+3
1.2883437 +4
.,
Argument Exp.
Argument
1.6251434
-1
-2.0454379
1.5239494
-1
-1.3755675
1.4441607
-1
-9.5014952
1.3944190
-1
-7.4485484
1.3752883
-1
-6.7651171
1.1284875
-1
-2.8603978
1.1054589
-1
-2.3559046
1.1098270
-1
-2.4353890
1.2738464
-1
-4.3132296
1.1519304
-1
-2.9827002
1.0442877
-1
-1.9827500
9.0181346
-2
-7.4068329
-5.8922431
-1
5.6190639
-2.6747958
+O
2.2334214
a3
Exp. Argument
Exp.
-5 2.5404935
-9
-5 1.2610922 -9
-6 6.2073358 -10
-6
3.8266182 -10
-6
3.1420473 -10
-6
8.5173702
-11
-6
3.9276248
-11
-6
4.5164488
-11
-6
1.3863582 -10
-6
7.4538667 -11
-6
3.3603790
-11
-7
-1.4487255
-11
-5
-2.1303241 -9
-4
-8.0665860
-9
84
Argument
Exp.
-1.1767904 -13
-4.4281251 -14
-1.5622497 -14
-7.4517277
-15
-5.4254872
-15
-1.1440038
-15
3.3369324 -16
1.8172612 -16
-1.5283798 -15
-3.7809957
-16
2.4513433 -16
9.4290495
-16
3.0369250
-14
1.0882779 -13
Error
Range (µ.VI
Exact-Approx.
-13 to 3
-4 to 7
-6 to 10
-7 to 13
-7 to 14
-.04 to .04
-.08 to .09
-.10to.12
-.002 to .002
- .011 to .011
-.0005 to .0005
-.0005 to .0005
-.11 to .08
-.0007 to .0007
~auadratic, cubic, and quartic approximations to the data as a function of voltage in selected temperature ranges (°C). The expansion is of the form
T = aa + a1 E+azE2+ a3E3+ a4E4 where E is in microvolts and T is in degrees Celsius .

Type B Thermocouples
5
Temperature
Range {°CI
I. Quartic Equation
0 to 900
Oto 1100
Oto 1400
0 to 1650
0 to 1820
400 to 1100
400 to 1400
400 to 1650
1050 to 1400
1050 to 1650
1400 to 1550
1400 to 1650
Reference Junction
Correction
0 to 50
ao
Argument Exp.
1.3740347 +1
-2.5321108 +1
-1.1708354 +2
-9.8446259 +2
-1.3702395 +3
-4.7644591 +2
-6.4878929 +2
•1
Argument Exp. Argument
-2.3614224 -1 5.7496551
-2.3893338 -1 5.7684447
-2.3476301 -1 5.7480761
-1.9185893
-1
5.5578879
-1.3749133
-1
5.3446673
-3.2914888 -1 5.9766638
-9.9736579 -2 5.4976533
3.9860894 -1 4.5539656
3.3670688
+0
8.2282215
4.6252371 +O -7.0976836
2.2890832
+O
1.5749253
2.7380621
+O
1.1375302
-2.4673839 -1 5.9050303
Exp. Argument Exp.
Argument
-3 -5.6339756 -7
-1.1808558
-3 -5.9963592 -7
-9.7041131
-3 -5.7165679 -7 -1.0838193
-3 -3.3057924
-7
-2.0018428
-3 -9.1094186 -8 -2.8098361
-3 -8.0141311 -7
-2.7203972
-3 -3.6623964 -7
-3.6969100
-3
3.6623964
-7
-3.6969100
-4 2.4061224
-6
-7.7901142
-4 3.2325686 -6
-9.4548852
-3 2.2417410 -6 -7.8471224
-3 2.4305578
-6
-8.1518033
-3 -1.2267180 -6
Exp.
-10
- 11
-10
-10
-10
-11
-10
-10
-10
-10
-10
-10
Error
Range (µVI
Exact~Approx.
-.22 to .14
-.18 to .20
-.7to1.0
-4 to 5
-8 to 9
-.05 to .05
-2.0 to 1.8
-2.0 to 1.8
-.05 to .05
-.05 to .05
-.05 to .05
-.05 to .05
-0.01 to + 0.01
5Quadratic, cubic, and quartic approximations to the data
as a function of temperature (°C) in selected temperature ranges. The expansion is of the form
E=ao+ a7T +a2T2+ a3T3+ a4T4 where E is in microvolts and Tis in degrees Celsius.

Type B Thermocouples
6
Temperature
Range (°C)
I. Quartic Equation
0 to 900
0tollllll
0 to 1-400
0 to 1650
0 to 1820
400 to 1100
400 to 1400
400 to 1650
1050 to 1400
1050 to 1650
1400 to 1550
1400 to 1650
•o
Argument Exp.
1.8946288 +2
2.0949015 +2
2.2354664
+2
3.2188156 +2
3.4418084 +2
3.7140306 +2
3.9253848 +2
.,
Argument Exp. Argument
Exp.
8.9244743 -1
-5.7447033
-4
7.2874066 -1
-3.1771931
-4
5.7822214
-1
-1.6039309 -4
4.9929130
-1
-1.0349686 -4
4.6255054 -1
-8.2176262 -5
3.0966136
-1
-5.8100680
-5
2.7222162
-1
-3.6930932
-5
2.4988761
-1
-2.7160312 -5
1.8282378 -1
-1.1561743 -5
1.7031473 -1
-8.9696912 -6
1.5828913
-1
-7.0050689
-6
1.4979551
-1
-5.7276293
-6
a3
Argument Exp. Argument
1.8053618
-7
-1.9719121
6.8254996
-8
-5.1002233
2.2187592 -8 -1.0678514
1.0792281 -8 -3.9111456
7.3717195 -9 -2.2913665
8.2483967
-9 -4.7591774
3.6830239
-9 -1.4483702
2.1299660
-9 -6.4220755
6.4320083 -10 -1.4544375
4.0789445
-10
-6.6410259
2.6714849
-10
-2.9082072
1.8192801
-10
-7.8042686
Exp.
-11
-12
-12
-13
-13
-13
-13
-14
-14
-15
-15
-16
Error
Range (µV)
Exact-Approx.
-30 to 75
-35 to 90
-45to110
-50to120
-50to130
-.09 to 1.0
-3 to 3
-5 to 5
-.003 to .003
-.025 to .020
- .001 to
.001
- .001 to
.001
•Quadratic, cubic, and 9.uartic approximations to the data as a function of voltage in selected temperature ranges (°C). The expansion is of the form
T""' ao + a1 E+ a2E2 +a3EJ + a4E4 where E is in microvolts and T is in degrees Celsius.

Type E Thermocouples'
Temperature
Range (°C)
I. Quartic l:quation
-270 to O
-200 to O
-200 to 800
-20to -500
0 to 400
Oto 1000
400 to 1000
600 to 800
850 to 1000
Reference Junction
Correction
Oto 50
•o
Argument Exp.
-8.5384268
+2
-1.3839633
+3
-5.1503130 +4
.,
Argument Exp. Argument
5.9287179 +1 7.0983783
5.8754764 +1 5.7443085
5.8043714 +1 5.6118501
5.8318735 +1 5.4292960
5.8327691 +1 5.3761106
5.8734697 +1 5.0789891
6.5022632 +1 3.4354900
6.7211126 +1 3.1669230
-1.6691278
+2 4.1877018
5.8637565 +1 4.6720025
03
Exp. Argument Exp.
-2 5.2421843 -5
-2 -5.0637772 -5
-5 -5.9506564 -5
-2 -5.6288941
-5
-2 -5.2870656 -5
-2
-4.7821793 -5
-2
-2.9769494 -5
-2
-2.9237913 -5
-1
-3.1228607
-4
-2
-1.4438022 -5
Argument
Exp.
3.8137875
-7
1.3960921
-7
2.2327737 -8
2.0825828 -8
1.5352840 -8
1.4669118
-8
7.6039401 -9
8.1514671 -9
8.5283044 -8
Error
Range lt-tVl
Exact-Approx.
-5 to 5
-.5 to .4
-60 to 30
-8 to 4
-3 to 4
-18to17
-2to2.5
-.03 to .03
-.06 to .06
-.12to +.24
'Quadratic, cubic, and quartic approximations to the data as a function of temperature (°Cl in sefected temperature ranges. The expansion is of the form
E =ao+ a1T + a2T2+a3T3+a4T4 where Eis in microvolts and Tis in degrees Celsius.