m

A 11 101 mb4 A2

NBS

PUBLICATIONS

NBSIR 32-2576

A Semiautomatic AC/DC Thermal

Voltage Converter Calibration

System

U.3. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Electronics and Electrical Engineering

Electrosyste.-ns Division

Washington, DC 20234

September 1932

Final Report

-QO-—

ored in part by

lOu Department of Defense

. U56

ration Coordination Group

<J2-23/6

19o2

C . 2

national bureau

OP STANDARDS

LIBRARY MAR U 1983

NBSIR 82-2576

A SEMIAUTOMATIC AC/DC THERMAL 2c?

VOLTAGE CONVERTER CALIBRATION

SYSTEM

K. J. Lentner, S. G. Tremaine

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

National Engineering Laboratory

Center for Electronics and Electrical Engineering

Electrosystems Division

Washington, DC 20234

September 1 982

Final Report

Sponsored in part by:

U.S. Department of Defense

Calibration Coordination Group

U.S. DEPARTMENT OF COMMERCE, Malcolm Baidrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

FOREWORD

The development of the system described in this report was partially

funded by the U.S. Department of Defense Calibration Coordination Group

(DoD/CCG). Members of the DC and LF Committee were from the Aerospace

Guidance and Metrology Center, Newark Air Force Station, Newark, Ohio 43055;

the U.S. Army Metrology and Calibration Center, Redstone Arsenal,

Huntsville, Alabama 35809; and the Metrology Engineering Center, Bureau

of Naval Weapons Representative, Pomona, California 91766.

The DoD/CCG project number assigned was CCG 79-123, and work was performed under NBS cost center 7220463.

In order to adequately describe the system discussed in this report,

commercial equipment and instruments are identified by manufacturer'

s

name and model number. In no case does such identification imply

recommendation or endorsement by the National Bureau of Standards, nor

does it imply that the material or equipment identified is necessarily

the best available for the purpose.

i i i

CONTENTS

Page

Foreword iii

LIST OF TABLES v

LIST OF FIGURES v

Abstract . . . 1

1. INTRODUCTION 1

1.1 Objectives 1

1 .2 Background 1

2. TECHNICAL APPROACH 2

2.1 Principle of Operation

2.2 Hardware Considerations 5

2.2.1 General 5 2.2.2 Measurement Procedures 6

2.3 Software Considerations 11

2.3.1 General 11 2.3.2 Operating Procedure for AC/DC Difference Tests ... 14

3. MEASUREMENT RESULTS AND UNCERTAINTIES 20

4. CONCLUSIONS AND RECOMMENDATIONS 23

5. ACKNOWLEDGEMENTS 23

6. REFERENCES 25

APPENDIX A. Hardware 26

APPENDIX B. ACDCHV Detailed Program Description

and Program Listing 34

iv

LIST OF TABLES

Page

Table 1. N-Test-F data 13

Table 2. ACCAL data 15

Table 3. Low voltage stability test data 16

Table 4. Stability test data summary 17

Table 5. AC/DC difference data 19

Table 6. Transport standard ac/dc differences (ppm) 21

Table 7. Range of ac/dc differences for transport standard (ppm) . 22

Table 8. AC/DC difference for TVC "FA 50" (ppm) 24

Table 9. AC/DC difference for TVC "FC 100" (ppm) 24

LIST OF FIGURES

Figure 1. Overall view of system 3

Figure 2. System block diagram 4

Figure 3. Simplified schematic of thermal voltage converter

(TVC) test circuit 7

Figure 4. Block diagram of system for calibrating an ac standard

or voltmeter 9

v
.
A SEMIAUTOMATIC AC/DC THERMAL VOLTAGE CONVERTER CALIBRATION SYSTEM

K. J. Lentner and S. G. Tremaine

Abstract

A semiautomatic ac/dc difference calibration system is

described. The system operates over a frequency range of 20 Hz

to TOO kHz, covering the voltage range from 0.5 V to 1 kV. For

all voltages at frequencies in the range from 20 Hz to 20 kHz,

the total uncertainty is 50 parts per million (ppm), and 100 ppm

for voltages at frequencies between 20 kHz and 100 kHz. In addition to ac/dc difference testing, the system can be readily

adapted to calibrate precision ac digital voltmeters or ac calibrators. Results of extensive intercomparison testing of

the new system against a manual test system are reported, using

a multi range thermal transfer instrument as a transport standard.

The results indicate that the ac/dc differences measured are well

within the combined total uncertainty limits of the two systems.

Key words: ac/dc difference; ac voltage measurement; automation;

calibration; metrology; thermal voltage converter.

1. INTRODUCTION

1.1 Objectives

The Semiautomatic AC/DC Thermal Voltage Converter Calibration System,

developed at the National Bureau of Standards and described in this report,

was designed to use electronic technology to overcome the deficiencies

of existing manual test methods. Specific objectives for the new system

included: 1) use of commercially available, programmable instruments

whenever possible; 2) elimination of the need for manual data entry into a computer for reduction; 3) elimination of the frequent data checks and

cross-checks required in manual tests; 4) elimination of as much operator

intervention as possible during the test procedure; 5) simplification of

necessary remaining interaction by providing displayed operator instruction

via computer control; 6) close control of the time interval between

application of both ac and dc voltages to the test circuit in order to

minimize drift effects; and 7) achievement of the same level of uncertainty

as is presently possible with manual testing methods.

1.2 Background

Techniques for performing precision ac/dc difference testing, not

only at the National Bureau of Standards (NBS), but also in other national

and industrial or governmental metrology 1 aboratori es , generally make use

of manual testing methods which utilize photocell preampl i fiers and lightbeam galvanometers as voltage detectors in conjunction with manually

1
balanced voltage comparators [1,2]J Careful attention to the elimination

or reduction of systematic and random uncertainties in testing methods,

range resistors, and thermoelements (TE's) has resulted in sufficient

confidence in test data to allow results to be reported with total

uncertainties at the 10-100 ppm level (or better, in some cases) over

wide voltage and frequency ranges [3,4]. These manual test methods,

however, are very time-consuming and subject to errors due to operator

fatigue. To overcome these deficiencies, and to expedite test report

generation, a semiautomatic ac/dc calibration system was developed.

Because of the low-level dc voltages that must be measured

(about 10 nV), large temperature coefficients of TE's, ac or dc source

instabilities, and dc reversal differences of TE's, stringent requirements

are placed upon the measurement system. In addition, light beam galvanometers

suffer the disadvantage of not being easily adaptable to automation.

However, with the advent of digital electronics, digital nanovoltmeters

are available with sensitivity, resolution, and accuracy sufficient

to meet the requirements of precision automatic ac/dc difference testing.

Programmable ac and dc voltage calibrators are also available which lend

themselves to adaption for automatic testing. Advances in analog/digital

interfaces have greatly improved the ease with which computers can be

used to control these instruments. The semiautomatic system which evolved

is shown in figure 1, and is described in detail in this report. The system

operates over a frequency range of 20 Hz to 100 kHz, covering the voltage

range from 0.5 V to 1 kV. For all voltages at frequencies in the range

from 20 Hz to 20 kHz, the total uncertainty is 50 ppm, and 100 ppm for

all voltages at frequencies between 20 kHz and 100 kHz. In addition to

ac/dc difference testing, the system can be readily adapted to calibrating

precision ac digital voltmeters or ac calibrators. Extensive testing of

the new system using a multirange thermal transfer instrument as a transport

standard indicates that the test results are well within the reported

uncertainty limits. In addition, data obtained with the system indicate

that total random uncertainties (3a limits) of about 3 ppm can be obtained

for some ac/dc difference tests.

2. TECHNICAL APPROACH

2.1 Principle of Operation

A block diagram of the semiautomatic system is shown in figure 2. In principle, the system is similar to the manual system presently used

at NBS for routine calibration work, except that overall system control

and data acquisition and processing are provided by a 16-bit minicomputer.

Programmable ac and dc standards supply the voltages to the thermal

converters (consisting of the TE and various range resistors). Such

voltage standards are often referred to as ac or dc calibrators. The

output voltages of the two converters (as well as the difference between

the two voltages) are measured in a semiautomatic mode by means of a

^Numbers in brackets refer to the literature references listed at the

end of this report.

2
Figure

1.

Overall

view

of

system
CRT and

Keyboard

(System

Console)

16-Bit

Minicomputer

System

RS-232C

RS-232C |

Interface

Modular Interactive

Data Acquisition

System (MIDAS)

RS-232C

TTY

(Test

Report)

Programmable}^

DC Standard

BCD

Interface

BCD

Interface

Programmable

AC Standard

Standard

Range

Resistor

Standard (PtH ,^/?Pa

.rJ

t0r

, ±$) Te“t

Thermo- —I (K-V Divider & \r~<^ Iesx

Potentiometer)

Thermo

element

Unit

Under

Low Thermal

Switches

Digital

Voltmeter

BCD Interface

Figure 2. System block diagram
manually operated TE comparator and a digital voltmeter which is

automatically controlled via the computer. The computer, its peripheral

equipment, and the Modular Interactive Data Acquisition System (MIDAS) [5] are interconnected utilizing the standard RS-232C interface. The

programmable instruments and the high voltage and 1 ow-thermal -noi se switches are controlled by the computer via the MIDAS digital interface.

In operation, the ac or dc voltages are applied simultaneously to

the standard TE and the unit under test (UUT). The difference in the

output voltages is primarily balanced out by the TE comparator. The small

residual differences in the TE output voltages are automatically measured

with the digital voltmeter as the inputs are switched between the ac and

dc voltages. Typically, the voltage differences are manually balanced to

less than 100 nV. The residual voltages are then measured with a resolution

of 10 nV, requiring a voltmeter with only moderate accuracy but with low

noise. In addition, the voltmeter is used to measure the nominal output

voltages of both converters.

2.2 Hardware Considerations

2.2.1 General

As mentioned previously, the components of the semiautomatic system

(except for the computer, its peripheral equipment, and interfaces) are similar to manual systems used at NBS. The principle differences for the

new system are the use of a sensitive digital voltmeter and programmable

dc and ac voltage standards. A listing of the hardware contained in the

system is provided in appendix A.

Overall system control is provided by means of a 16-bit minicomputer

which has 64 kbytes of core memory and a dual floppy-disk unit for program

and data storage. The system console (CRT), the teletypewri ter (TTY),

and MIDAS are connected to the computer by means of interfaces which

conform to the EIA RS-232-C standard [6]. MIDAS hardware is based on the

CAMAC standard [7] and consists of several functional modules which are inserted into slots in an equipment rack. A power supply and MIDAS

controller module also are required to make the MIDAS system operational.

Communication between the controller module and individual MIDAS modules

is in accordance with the ASCII standard code for information interchange [8].

The dc and ac voltage standards must have wide voltage and frequency

ranges to meet the requirements of calibration work for which the system

is intended. In addition, the standards must be stable and have sufficient

resolution to permit precision measurements to be made. The dc voltage

standard has ranges of 10 V, 100 V, and 1 kV with resolutions of 1 yV,

10 yV, and 100 yV per step, respectively, with ten steps per range.

The specified accuracy is about 30 ppm of range for all three ranges,

with output stability of about 15 ppm of programmed output per month.

The ac voltage standard has seven decade ranges covering the voltages

from 1 mV to 1 kV (full-scale ranges) with a resolution of 10 ppm of

range per step, with ten steps per range. The frequency ranges consist

5
of eleven fixed frequencies per range, covering the range 10 Hz to

110 kHz, with frequency range multipliers of XI 0 Hz and XI 00 Hz, XI kHz

and X10 kHz. The accuracy of the ac standard's voltage output varies

with frequency, from about 0.02% to 0.05% of voltage setting. The voltage

stability is specified as 0.01% of setting for six months.

The digital voltmeter has eight ranges from ±10 yV to ±100 V.

On the most sensitive 10 yV range, it has a resolution of 10 nV, with

an input impedance of about 10 Mn. The zero stability is specified

as less than 100 nV per hour. In the frequency range dc to about 10 Hz,

the voltmeter has less than 50 nV of rms noise, referred to the input,

with the input shorted.

It should be noted that two digital panel meters used to monitor the

outputs of the voltage standards, as well as a frequency counter used to

monitor the ac frequency, are not included in figure 2 (for simplicity),

but they are visible in figure 1. The large instrument on the left of

the test console table (fig. 1) is an ac calibrator under test.

A critical problem in making nanovolt measurements is that of obtaining

switches which have 1 ow-thermal -noi se, and can be controlled automatically.

Ideally, TE output voltages of about 10 mV should be measured to within

1 ppm (10 nV). Mercury-wetted contact, self-latching, solid-state and

reed relays were found to be unsuitable since these types have thermal

noise on the order of 1 y V. The problem was solved by modifying manually

operated 1 ow-thermal -noi se switches. Solenoids with 24 -V operating

coils were mechanically linked to such switches. The operating coils

are energized by programmable MIDAS relays which connect the 24- V supply

to the coi Is.

The switches which apply the ac or dc voltages to the test circuit

are electro-mechanical relays capable of switching up to 5 kV. The 24-V

operating coils of these relays also are controlled by MIDAS relays.

2.2.2 Measurement Procedures

The various measurement steps will now be explained in some detail

for the determination of ac/dc difference, and for determination of the

corrections to the nominal output voltages of an ac voltage standard.

A portion of the circuit for ac/dc difference testing, including the

components of the TE comparator, is shown in figure 3. The thermal

voltage converter (TVC) No. 2 can be either the standard or test converter.

The only requirement is that E£ must be greater that E-j and, for purposes

of this discussion, it is assumed that the test TVC is in the No. 2

position. With rated dc voltage applied, and with the potentiometer (P)

turned off, the emf outputs (E? of the test unit, E] of the standard)

are measured by the digital voltmeter (DVM) with switch K2 closed.

Another switch in the TE comparator (not shown in fig. 3) permits

6
+DC

-DC

OO

I" o>H 7

Figure

3.

Simplified

schematic

of

thermal

voltage

converter
manual selection of either the £3 or E-j voltages. With the voltmeter

reading E 2 > the potentiometer is adjusted until the voltmeter indicates

about 500 n V. Switch K2 is opened, K1 is closed, and the Kel vi n-Varl ey

divider is adjusted until the voltmeter indicates about 100 nV. The test

then proceeds automatically, and ac, dc+, dc-, and ac voltages are applied

(in the order listed) to the test circuit [2]. The difference voltages

between the outputs of the test and standard thermal voltage converters

are measured for all four input voltages.

The ac/dc difference, in ppm, for the unit under test, as derived in

[ 2 ], is

6

t

i

where 6 $ is the correction to the standard, E<j is the average emf of

the standard TE with two directions of dc voltage applied, E a is the emf

of the standard TE with ac voltage applied, n

s is a dimensionless factor

(£2) of the standard, and E

s is the output emf of the standard TE at rated

dc voltage input. If E<j - E a is measured in nanovolts, and E s in

millivolts, the expression for ot is conveniently given in ppm, provided

that <5 S is in ppm.

If the standard TE has a higher output emf than the test TE, the

previous expression is modified to become

6

t

5

where all terms and units are as previously defined, and E^ is the output

emf of the test TE at rated dc voltage input.

A block diagram of the system when used for calibrating an ac standard or voltmeter is shown in figure 4. As shown in this figure,

the system's ac standard is connected for testing. However, the UUT,

indicated as "AC STD," could as well be an external ac standard or a precision voltmeter. K1 and K2 are the dc+ and dc- high voltage switching

relays, K3 is the ac high voltage relay, and K4 is a 1 ow-thermal -noi se switch. Using this test circuit, the corrections to the nominal output

voltage (at a given dial setting) of an ac standard can be determined

3
MINICOMPUTER

h*

MIDAS

r-H"

9
by using the system's programmable dc voltage standard (set to the same

nominal value as the ac standard) and a thermal voltage converter, both

having known corrections. For this case, only the Lindeck potentiometer

(P) of the TE comparator is used. The correction to the UUT, in ppm, is

‘ e h

Ci » 6 + — + C , , 1 s nE dc

where 6s is the ac/dc difference correction (in ppm) of the TVC at

the test frequency, E a is the reading of the voltmeter (DVM) with ac voltage applied (i.e., the difference between the TE's output emf and

the fixed voltage of the Lindeck potentiometer), E^ is the average of

the DVM readings with direct voltage of both polarities applied, n is a dimensionless factor equal to 2 if the TE has a square-law response, E is the TE's output emf at the applied test voltage, and C<j c is the

correction (in ppm) to the dc voltage standard's nominal output. As

for ac/dc difference tests, the equation is conveniently given in ppm if

E

a

- Eq is in nanovolts and E is in millivolts, with 6 S and C^c also in

ppm.

The denominator of the correction equation contains the dimensionless

characteristic "n." Most TE's do not have an ideal square-law response,

hence, the value of n must be determined. Since n generally ranges in

value from 1.6 to 2, neglecting to measure a TE's actual value of n* can lead to significant errors in the correction to the UUT. For example,

in the worst case, if n is assumed to be 2, but actually is 1.6, then

the error amounts to ( 2-1 . 6) /

( 2) = 0.2, or 20 percent of the correction.

The procedure for measuring n (to a first order of approximation) is

based on the fact that a TE's output voltage (E) can be expressed as

n E = kl ,

where I is the current through the TE's heater element.

Therefore,

n-1

dE = knl dl,

and dE/E = ( k n

I

P “

‘ d I ) /( k

I

R

)

.

Hence, dE/E = n (dl/I )

,

10
and, assuming constant heater resistance and a stable voltage source,

dE/E « n (dV/V)

,

where V is the dc voltage applied across the series combination of a range

resistor and a TE.

Two techniques can be used to measure the characteri sti c n. One

involves making small, accurately known changes in the voltage (AV).

The second involves making changes in the TE's heater current (I) with

the applied voltage held constant. In the second method, which is used

for the MIDAS-based system, small changes in the heater current through

the TE under test are obtained when a 400 Q resistor, in series with a 40 kn range resistor, is shorted by closing a MIDAS relay.

2.3 Software Considerations

2.3.1 General

In order to reduce the effort involved in making routine tests,

the software for the system was designed to provide as much interaction

between the system console and the operator as possible. This interaction

is used to reduce the possibility of damage to either the standard or UUT when either software or hardware failures occur. Also, by progressing

logically through the initialization portions of the test routines, the

operator, when necessary, can take whatever corrective actions might be

required. A significant advantage of the resulting software design is

that sufficient warm-up time is automatically provided between application

of the various test voltages so that the effects of errors due to the

warm-up drifts of the standard and test units are reduced. In addition,

the computer closely controls the time intervals between voltmeter readings;

hence, the effects of linear drift are minimized.

The programs, which are written in BASIC, provide the means for

automatically setting the ac or dc voltages and ac frequency, operating

the voltage relays and 1 ow-thermal -noi se switches, triggering the voltmeter

to obtain voltage readings, and storing these readings in the computer

memory. Six programs constitute the major testing software package.

Program ACDCLV is used for making ac/dc difference tests at voltages

from 0.5 to 95 V, and ACDCHV is used for similar tests at voltages greater

than 1 05 V up to 1 kV.

Since the major application of the work described in this report is

ac/dc difference testing, a typical sequence of operations for this type

of testing is described below where the ACDCHV program is discussed.

The other five programs will only be mentioned briefly; however, detailed

information is available upon request.

11
ACDCHV is a program which provides partial automatic control of

ac/dc difference testing at voltages greater than 105 V. Since the

MIDAS interface does not have isolated analog and digital grounds, it was necessary to develop a separate software package for high-voltage

testing. At high voltages, it was found that operating either the ac or dc voltage relays introduced transient voltage surges into the MIDAS

digital circuitry. The MIDAS controller interpreted these surges as voltage level changes identical to programmed commands. The result was that incorrect relays might be opened or closed, the voltmeter might be

falsely triggered to obtain a reading, or any other of a series of

unwanted events might occur. Hence, the ACDCHV program was developed

to ensure that no high-voltage standards are turned on whenever a voltage

relay is operated. To avoid unnecessary operation of the high-voltage

relays, program ACDCLV should be used for tests below 100 V.

Basically, ACDCHV contains three general sections. At the beginning,

test documentation (e.g., date, test number, observer, and instrument) is

requested. String and array variables are dimensioned, and various simple

variables are initialized. A heading for the test documentation is

created by the operator. The midsection includes a network of subroutines

that interact with the operator. Displayed instructions prompt the

operator to define test parameters for setting ac and dc voltages, to

switch the TE comparator from E-high to E-low, and to initially balance

the Kel vi n-Varl ey divider and rebalance it when necessary. Repeatedly

accessed subroutines close and open the appropriate relays, set the input

voltages, determine the TE emf output voltages, trigger the voltmeter to

read the TE difference voltages, and calculate the ac/dc difference of

the UUT for four determinations at each test point. Finally, statistical

calculations are performed and the results are printed on the TTY.

Options are then provided for the operator to choose whether to stop,

repeat a test with or without averaging, or change parameters and run another test.

Program NTSTF is used to determine a TE's dimensionless factor, n [1,2].

The variation of n as a function of a TE's heater current can be expressed

as n = g (E), and this function is assumed to vary linearly. The program

automati cal ly fits a least-squares line to the data. The computational

techniques used are fully discussed on pages 5-10 of [10]. Typical test

results are illustrated in table 1.

12
Tabl e 1 . N-Test-F data

DATE . . THUR. 29 MARCH 79 OBSERVER.. . .KJL

TEST NO. . . . N-TEST INST NO. . .FA

VOLTS E N AVE.N NE 500/

N

100 2.70 (1.992 1.991 1.990 1.990) 1.991 5.37 251 .2

100 2.70 (1 .988 1 .988 1.989 1.991) 1.990 5.37 251 .3

120 3.88 (1.973 1.973 1 .974 1 .975) 1.974 7.66 253.3

120 3.88 (1 .973 1.974 1.975 1.975) 1.974 7.66 253.3

140 5.24 (1.954 1.955 1.956 1.956) 1.955 10.25 255.7

140 5.24 (1.954 1.955 1 .957 1.956) 1.955 10.25 255.7

160 6.79 (1.922 1.923 1.925 1.923) 1 .923 13.06 260.0

160 6.79 (1.922 1.923 1.924 1.923) 1.923 13.06 260.0

180 8.50 (1 .881 1 .881 1 .883 1 .882) 1 .882 16.00 265.7

180 8.50 (1.878 1.881 1 .883 1.882) 1 .881 15.99 265.8

200 10.34 (1.833 1.833 1.835 1.833) 1.833 18.96 272.7

200 10.34 (1.826 1 .832 1.834 1 .834) 1 .833 13.95 272.8

THE CURVE FITTING PROCESS USES A LEAST-SQUARES FIT

FOR A POLYNOMIAL OF DEGREE ONE. THE N (LOWER CASE)

TE CHARACTERISTIC (Y-AXIS) VERSUS TE EMF (X-AXIS) IS

ASSUMED TO BE A LINEAR FUNCTION OF THE FORM Y = B+MX

OR, IN THIS CASE:

MI = M-NE

WHERE NI = TE CHARACTERISTIC

M = ZERO X INTERCEPT

N = NEGATIVE OF CURVE SLOPE

E = TE OUTPUT EMF

M = 2.05518

N = 206568E-1

13
ACCAL is a program used to calibrate an ac voltage standard,

a precision ac digital voltmeter, or the ac standard of the system in

terms of a thermal voltage converter and the system's calibrated dc

standard, as discussed in the previous section. Results for the

calibration of an ac voltage standard are illustrated in table 2.

The last column, "T CORR PPM," shows the correction to the calibrator's

nominal output voltage.

Stability of the system's dc and ac standards can be checked by

using programs called STABLV and STABHV. These progams are used for

voltage ranges similar to those for ACDCLV and ACDCHV. Occasionally,

test results appear to be erratic. These stability tests are useful in

determining if the supplies are functioning properly. Stability of the

sources is measured by using a programmable 6-1/2 digit multimeter

whose function, ranges, and reading rates are remotely controlled.

Initial stability test parameters for voltage, frequency, time

between readings, and total number of readings are defined by the

operator. The program then exercises automatic control over the ac and

dc standards, the voltage relays, and the voltmeter. At completion,

stability data including the values of minimum, maximum, range, average,

standard deviation of the mean, and three times the standard deviation

of the mean (calculated 3a limits) for both ac and dc voltage readings

are printed on the TTY. Table 3 shows the results of a test at 95 V,

50 kHz, with the voltmeter programmed to use a 10-second integration

time. The total time for the test illustrated was about 12 minutes,

which is about the time it takes to do a test run (i.e., four

determinations) for ac/dc difference tests at one frequency and voltage.

The advantages of the stability tests are illustrated in table 4.

The difference -in the ranges of the ac voltage for tests at 95 V and

200 V indicates that the ac high-voltage amplifier had become unstable.

The instability was verified by a 12-minute test in which the ac voltage

range was about 1150 ppm at 20 V as opposed to about 347 ppm at 95 V.

In addition to the test capabilities discussed above, the methodology

and computer programs were developed for testing one model of a precision

multirange automatic thermal transfer instrument as a voltmeter. Detailed

information is available and can be supplied upon request.

2.3.2 Operating Procedure for AC/DC Difference Tests

For the reader not interested in the operational details of this

program (contained in appendix B), the following overview is provided.

The specific operating procedures include the following steps and

instructions:

1) Input via the system console, the test number, voltage, frequency,

observer's name, and code for the standard thermal converter.

2) Visually check to see that both software and hardware are operating correctly by checking the system's digital panel meters and

frequency meter for correct readings of the outputs from the ac and dc

standards. If the outputs are incorrect, repeat step 1.

14
Table 2. ACCAL data

DATE . . . OBSERVER. . TEST NO INST. •

KHZ *CORR V TEST STANDARD E NE T CORR

PPM RANGE TE RANGE MV PPM

100.0 100.0 FB 100.0 10.4 18.6

0.8 0 (7 8 7 10) -8 -8

0.8 0 (7 6 7 3) -7 -7

0.8 0 (7 8 8 3) -7 -7

0.8 0 (5 1 4 3) -6 -6

2.4 0 (29 32 33 33) 32 32

2.4 0 (30 35 34 35) 33 33

2.4 0 (32 35 25 38) 33 33

2.4 0 (31 31 32 35) 33 33

4.8 0 (278 282 281 284) 281 281

4.8 0 (278 284 284 283) 282 282

4.8 0 (278 284 284 285) 282 282

4.8 0 (281 283 285 283) 283 283

0.4 0 (11 13 10 9) 11 11

0.4 0 (3 8 9 8) 8 8

0.4 0 (5 8 9 9) 8 8

0.4 0 (5 9 11 8) 8 8

15
Table 3. Low voltage stability test data

READING DC-VOLTAGE PPM AC-VOLTAGE PPM

NO. 1 95.00530 55.9

***

NO. 1 (A) 94.51200 -5136.9

NO. 2 95.00530 55.9

NO. 2 (A)

***

94.51300 -5126.3

NO. 3 95.00530 55.9 ***•

NO. 3 (A)   94.51200 -5136.9

NO. 4 95.00540 56.5

** *

NO. 4 (A) **•*•* 94.51200 -5136.9

NO. 5 95.00530 55.9

NO. 5 (A) ****   94.51200 -5136.9

NO. 6 95.00530 55.9 ** **  •

NO. 6 (A) ** ** 94.51100 -5147.4

NO. 7 95.00510 54.0  

NO. 7 (A) 94.51000 -5158.0

NO. 8 95.00510 54.0

NO. 8 (A) ** **   94.50800 -5179.0

NO. 9 95.00520 54.6

NO. 9 (A) ** **   94.50700 -5189.4

NO. 10 95.00510 54.0

NO. 10 (A) ** ** ***

94.50700 -5189.4

DC

NO. OF

READINGS

MEAN

(PPM)

STAN. DEV.

OBSERVATION

STAN. DEV.

MEAN

STAN. DEV

MEAN *3'

10 55.3 1.0 0.3 1.0

MIN = 53.9679 MAX = 56.5378 RANGE = 2. 5699

AC

NO. OF

READINGS

MEAN

(PPM)

STAN. DEV.

OBSERVATION

STAN. DEV.

MEAN

STAN. DEV

MEAN *3

10 -5153.7 23.9 7.5 22.6

MIN = 5189.43 MAX = -5126.31 RANGE = 63 .1211

V- NOMINAL

95

FREQUENCY

50 kHz

INT. TIME

10 SEC

TIME DELAY

10

16
Table 4. Stability test data summary

Program: STABLV - Overnight (17 hr) Test

DC

No. of

Readings

Mean

(PPM)

Stan. Dev.

Observation

Stan. Dev.

Mean

Stan. Dev

Mean *3

50

Min = 36.7817

42.1

Max

5.0

= 56.5378

0.7

Range = 2.1

19.7561

AC

No. of

Readings

Mean

(PPM)

Stan. Dev.

Observation

Stan. Dev.

Mean

Stan. Dev

Mean *3

50

Min = 84.1643

216.6

Max

51.0

= 431.583

7.2

Range =

21 .6

347.419

V-Nomi nal Frequency Int . Time Time Delay

95 1 kHz 10 sec 57500

Program: STABHV - Overnight (17 hr) Test

DC

No. of

Readings

Mean

(PPM)

Stan. Dev.

Observation

Stan. Dev.

Mean

Stan. Dev

Mean *3

50

Min = 9.99451

17.1

Max

2.7

= 19.989

0.4

Range = 1.1

9.99451

AC

No. of

Readi ngs

Mean

(PPM)

Stan. Dev.

Observation

Stan. Dev.

Mean

Stan. Dev

Mean *3

50

Min = -25400

-4168.96

Max

428.0

= -23450

60.5

Range = 181 .6

1949.99

V-Nomi nal Frequency Int . Time Time Delay

200 50 kHz 10 sec 3000

Program: STABHV - 12 Minute Test

DC

No. of

Readings

Mean

(PPM)

Stan. Dev.

Observation

Stan. Dev.

Mean

Stan. Dev

Mean *3

10

Min = 9.99451

10.0

Max

0.0

= 9.99451

0.0

Range = 0.00

AC

No. of

Readi ngs

Mean

(PPM)

Stan. Dev.

Observation

Stan. Dev.

Mean

Stan. Dev

Mean *3

10

Min = -24750

-3890.0

Max

433.9

= -23600

137.2

Range = 411.6

1149.98

V-Nomi nal Frequency Int . Time Time Delay

200 50 kHz 10 sec 5

17
3) Manually set the TE comparator to its "high TE" voltage input

position, and switch the voltmeter to its 10-mV range. The program

automatically closes the dc voltage relay and a~l ow-thermal -noi se switch

(K2) turns on the dc standard and triggers the voltmeter to obtain the

TE voltage output reading.

4) Switch the TE comparator to its "low TE" voltage input position.

The program then triggers the voltmeter to read the voltage. The values

of the high- (from the previous step) and low-voltage readings are compared.

If the latter is actually larger in magnitude than the former, the operator

is instructed to interchange the two TE inputs after the dc voltage has

been turned off. The program automatically stores the correct value of

E-low, since that value is used in the equation to determine the ac/dc

difference of the test unit (see section 2.2).

5) Switch the TE comparator to the "high TE" voltage input position.

This step in the procedure is done only if the test unit actually has a greater emf output than the standard. If not, the comparator switch

remains in the "low TE" voltage input position. In either event, the

operator is then instructed to turn on the Lindeck potentiometer, change

the voltmeter to its 10 yV range, and manually adjust the potentiometer

until the voltmeter indicates about 500 nV.

6) Switch K2 is opened, and a second low-thermal noise-switch ( K1

)

is closed. The operator now manually adjusts the Kel vi n-Varl ey divider

until the voltmeter indicates a voltage within the range ±100 n V.

7) Switch K1 is opened, K2 closed, the ac voltage relay is closed,

the ac standard turned on, and its voltage is automatically incremented

or decremented until the output voltage of the UUT's TE is _< 1 yV of

its value with dc voltage applied, as in step 6.

8) At this point, the manual initialization process is complete,

switch K2 is opened, K1 is closed, and the test proceeds automatically

under program control. A sequence of voltage readings is obtained by

the voltmeter when ac, dc+, dc-, and ac voltages are applied to the

standard thermal voltage converter and UUT. These four voltage readings

are each obtained from the average of ten readings of the voltmeter.

The standard deviation of the ten readings is computed, and if this value

is < 200 nV, the program continues. If the standard deviation is _> 200 nV,

due to drifts in either the standard converter or the UUT, or the ac or

dc standards, or any of these effects combined, the series of ten readings

is repeated. After five attempts, if the voltmeter readings have not

stabilized, the test is aborted.

9) The sequence of readings with ac, dc+, dc-, and ac voltages

applied constitutes one determination of the ac/dc correction to the UUT.

The process is continued for four determi nati o/is ; the average value of

four determinations is computed and printed. The operator then may

elect to repeat the test, change voltage range or frequency, or stop the

test. A sample of data printed on the tel etypewri ter is illustrated in

table 5. Although only low-voltge test results are shown, the data

format is identical for high-voltage tests.

18
Table 5. AC/DC difference data

DATE 10/18/78

OBSERVER BC TEST NO NBSTES

INST FA50 APP STANDARD ES ET NSEL

V RANGE TE RANGE MV MV N*MV

30.0 50.,0 FD 100.0 4.5 3.3 6..40 kHz COR AC/DC DIFFERENCE STD AVE T PPM DEV COR PPM 50.0 -2 ( 273 279 280 277) 3.2 275.3

50.00 -2 ( 275 282 281 289) 4.9 277.5

30.0 50..0 FD 100.0 4.5 3.2 6..38 kHz COR AC/DC DIFFERENCE STD AVE T PPM DEV COR PPM 20.00 0 ( 100 121 105 100) 9.7 106.4

20.00 0 ( 102 107 no 117) 7.6 107.6

20.00 0 ( 97 101 106 105) 7.0 105.7

50.0 50. 0 FD 100.0 11.2 8.4 14..92 kHz COR AC/DC DIFFERENCE STD AVE T PPM DEV COR PPM 50.00 -2 ( 278 280 279 279) 1.1 277.1 50.00 -2 ( 280 280 280 281 ) 1.0 277.7

50.00 -2 ( 285 285 284 236) 2.7 279.4

50.0 50. 0 FD 100.0 11.2 8.4 14..92 kHz COR AC/DC DIFFERENCE STD AVE T PPM DEV COR PPM 20.00 0 ( 106 109 106 105) 1.6 106.4

20.00 0 ( 107 104 105 106) 1.4 106.0

50.0 50. 0 FD 100.0 11.2 8.4 14..92 kHz COR AC/DC DIFFERENCE STD AVE T PPM DEV COR PPM 10.00 0 ( 51 52 51 52) 0.5 51.5

10.00 0 ( 35 34 29 33) 10.1 42.2

10.00 0 ( 43 43 41 41) 8.1 42.1 10.00 0 ( 39 43 44 43) 7.0 42.1 50.0 50. 0 FD 100.0 11.2 8.4 14..92 kHz COR AC/OC DIFFERENCE STD AVE T PPM DEV COR PPM 5.00 0 ( 19 21 19 18) 1.5 19.4

5.00 0 ( 20 19 20 18) 1.1 19.3

NUMBER OF READINGS-H= . .64

NUMBER OF INDEP. TESTS=L= 6

DEGREES OF FREED0M=D1 = 58

POOLED ESTIMATE OF TEST STD. DEV. OF MEAN=S2

=S. D.T. (SEE S.P. 300, V.l, P. 316-40) =1.02083

19
3. MEASUREMENT RESULTS AND UNCERTAINTIES

There are many factors which contribute to the uncertainty of

ac/dc difference measurements of the type described in this report.

Similar manual systems have been in operation for many years at NBS and

their uncertainties have been documented [1-3]. DC reversal difference

of a TE, self-heating and ambient temperature effects, drift effects due

to non-equal time intervals during the voltage measurements, unbalanced

lead impedances, and induced voltages from electromagnetic fields are some of the more common factors. The process of determining an estimated total uncertainty for a system is based upon experience with

the system, careful measurements of standards with accurately known

corrections, or intercomparison tests of two independent test methods [3].

The latter procedure, involving comparison of a wel 1 -characteri zed manual

system with the new one, was followed, since the uncertainty sources are believed to be similar in both systems.

The system performance was verified by an extensive testing procedure

which involved the use of a multi -range thermal voltage converter instrument

as a transport standard. The transport standard was first tested for ac/dc

differences at various combinations of applied voltages and frequencies

using the MIDAS-based system. It was then tested, at similar voltages

and frequencies with the same standard thermal voltage converters, using

the manual testing technique which has been used for many years at NBS.

A third test was performed, again using the MIDAS system. Finally, the

MIDAS system was disassembled, physically relocated, reassembled, and

tested for proper operation. Then the transport standard was tested a fourth time, again using the MIDAS system. It should be noted that not

all voltage range-f requency combinations were tested for all four tests.

However, in those cases where fewer than four tests were performed, the

results indicated sufficiently small differences between at least two

independent test methods to establish that further testing was not

warranted. The results of these independent intercomparison tests are listed in table 6, and the range of ac/dc differences is listed in table 7.

In evaluating these results, it must be remembered that, for calibrating

multi range instruments like the transport standard, the manual test

system has uncertainties of the same magnitude as the semiautomatic

system. Hence, combined total uncertainties of the order of 100 and

200 ppm are possible depending upon the test frequency.

In table 7, the column listing "Voltage Range" refers to the input

voltage range of the transport standard, the "Test Voltage" is the actual

test voltage applied, and the different columns for frequency are the

actual test frequencies used. The numbers listed under the frequency

columns are the maximum differences (in ppm) of the calibrated ac/dc

difference corrections for the transport standard as determined for at

least two, and up to a maximum of four, of the test conditions described

above. That is, the numbers reported are the range (magnitude of the

maximum minus the minimum) of the ac/dc difference corrections measured

for each test voltage and frequency. The total elapsed time between the

first and final tests of the transport standard was about eight weeks.

20
Table

6.

Transport

standard

ac/dc

differences

(ppm) i Nz

jooo

Nl z

_x: o03

_NOCM

05 ,

03 03 • i 1 1 i • : 1 1 • • • • 1 • o i 1 1 i 1 1 CO CM CO CO 1 o CM z — 1 i CO 03 ( 00 05 • • 1 1 | • • 1 1 1 i 1 • CM r— 1 1 I CM CO 1 1 1 i 1 o CO o 1 z <— <— o o o o o o o o o o o CM • • • • • • • • • • • p"- CO co 03 CO O CM CO CO CO 00 r-* • CO 05 r— r— r— 1 r— 03 CO CM o fmmm 1 1 CM z 1

CO CO CM CO '

05 CO CO P-. o CM o 03 03 *3" CO CM CO CO CO o z o CM r— 1 1 o 03 CO r— f— 1

i P-. o 1 r—

*3* ,

CO CO CM CO • • • • • • • • CO 1 1 1 1 | 1 CO 1

o CO 05 CO O 05 1 1 1 1 l 1 CO 1 co CO CM z CO1 CM

CO 05 05 CM 05 • • 1 1 . 1 • • 1 1 1 1 1 1 • CM r— 1 1 1 03 CM 1 1 1 1 1 1 o o z r—

CM o o o O o O o o o o o O o • « • CM *3- <3- r— CO CO r> CO 03 o p

CM r— t CO CO 05 z •” 1 CM

CO CO 03 CO CO o 03 o 03 •3- CO 6 CO 1"- oo CM CO CM O p^ 1 z o r-. p— r—

r— r— CO CO CO ' CO1 1

*3- CM CO r— CO r— o CO • • i i | 1 n i • • • • • • O 05 i i i 1 i i 03 05 CO CO 03 z <3- CVJ1 CO

CO r". • • • i i 1 • • 1 1 I 1 1 i o 1-^ CO i i 1 r— o 1 1 1 1 1 i z 03 CO 1—

CM

O o o o o o o o o o o c o o r-. 03 fmmm CO P-. CO o CO 03 05 C3 z CO •— CM CM 1

*3" 05 CM CO o o 05 CO 1— '03 CO 03 • • • • • • • • « • • • • 1 o CO CO CM P-* 05 03 CM CO CO CO o * z 03 CO <— <— CM c I I • I I I

I I I I «3-

CC

CM oCMo <u <D CD in •f ra +j • 4-> « 

CL i—C

Q.

O > < >

gjc ;

<TD I

03o

03oI 03CM I 03o’,— CM

CMI

CO

'cri CM

CO

CO

COI

<=r

CM

COI CO

CO o — CO

CMCOI CO o03«3" CO

CM

CO

co

03

COCM*3" CO

OoCMo03CM

03CM I I I I I I o o o o 03 03 oo c

03 oo oo I I I o

03CM o

03

Qim

>. ooo

<25

<x> m5?3

*ooI CM I CO I

Repeat

Automatic

System
Table 7. Range of ac/dc differences for

transport standard (ppm)

Vol tage

Test

vol tage Test Frequency (kHz)

ranqe (volts 20 50 100

0.25-0.5 0.5 18 19 23

0.5 - 1 1 9 2 4

1 - 2 2 1 6 9

2 - 4 3 2 0 0

4 - 8 8 0 1 3

8 - 16 16 8 15 3

16-32 30 8 10 9

32 - 64 50 3 3 10

64 - 125 98 2 6 12

125 - 250 200 4 2 14

250 - 500 500 4 50 39

500 - 1000 500 22 54 147

500 - 1000 1000 17 70 --
The test results show that at 20 kHz the average value of the

range of ac/dc differences for all voltages is only 8 ppm. At 50 kHz the

average value of the range is 19 ppm, and at 100 kHz, where skin effects

and stray capacitance effects predominate, the largest range (at 500 V) was 147 ppm. However, this large range is within the expected combined

total uncertainty of 200 ppm for the two systems. Even with this one range greater than 100 ppm, the average value of the range at 100 kHz is

still only 23 ppm. No intercomparison results were obtained at 1000 V,

100 kHz, since the high-voltage-amplifiers in both systems could not

supply sufficient power at that vol tage-f requency combination.

Additional intercomparison tests were made using a single-range,

coaxial type thermal voltage converter with large, but accurately

known, ac/dc differences. The summary of the test results is shown in

table 8. From the data, it is obvious that the two systems agreed well

within the estimated total uncertainty limits.. In fact, the data clearly

show that the MIDAS-based system performed much better than had been

anticipated when the project was undertaken.

As a final check of the system's performance, intercomparison

tests were made using a single-range, coaxial type converter, which is

used as a working standard for ac/dc testing at NBS. The results of

these tests are summarized in table 9. Again, the results indicate

excellent agreement between the two systems.

4. CONCLUSIONS AND RECOMMENDATIONS

The results of the work reported indicate that it is possible to

measure ac/dc differences semi automatical ly with uncertainties about the

same as those obtained with manual testing techniques. The major advantage

of the system appears to be the elimination of most of the tedium involved

in manual testing, in which deflections of light beam galvanometers must

be observed and recorded.

For future work, it appears that further improvements in system

operation can be obtained by development of self-balancing TE comparators.

Additionally, by taking advantage of improvements in digital voltmeter

sensitivity, stability, linearity, and resolution, desktop computers,

and system components whose operation is compatible with new digital /analog interfaces, it may be possible to develop improved ac/dc

difference testing techniques.

5. ACKNOWLEDGEMENTS

The authors are indebted to C. B. Childers who made many of the

tests, assembled the equipment, and helped the programmers test tne

software. E. S. Williams designed and built the 1 ow-thermal -noi se and

high-voltage switching modules, and provided some of the initial software

which eventually became part of the total programming package.

R. E. Kleimann, S. C. Bailey, and W. C. Caterisano each contributed

portions to some of the computer programs. Thanks are also due B. A. Bell

who provided helpful comments, encouragement, and support.

23
Table 8. AC/DC difference for TVC "FA 50" (ppm)

System

1 Appl ied

vol tage

2

Frequency

kHz

3

Manual

4

MIDAS

3-4

Di fference

50 5 24 22 2

50 10 52 50 2

50 20 116 113 3

50 50 308 305 3

Table 9. AC/DC difference for TVC "FC 100" (ppm)

1 Appl ied

vol tage

2

Frequency

kHz

3

Manual

4

MIDAS

3-4

Di fference

100 20 3 5 -2

100 50 3 4 -1

100 100 13 18 -5

<

2 *
6. REFERENCES

[1 ] F. L. Hermach, E. W. Williams, Thermal Converters for AudioFrequency Voltage Measurement of High Accuracy, IEEE Trans.

Instrum. Meas., Vol . IM-15, pp. 260-268, Dec. 1 966.

[2] E. S. Williams, Thermal Voltage Converters and Comparator for Very

Accurate AC Voltage Measurements, J. Res. Nat. Bur. Stand. (U.S.).

75C: 145-154, Dec. 1971.

[3] F. L. Hermach, AC-DC Comparators for Audio-Frequency Current and

Voltage Measurements of High Accuracy, IEEE Trans. Instrum. Meas.,

Vol. I M— 25 , pp. 489-494, Dec. 1 976.

[4] R. S. Turgel , A Comparator for Thermal AC-DC Transfer Standards,

ISA Trans., Vol. 6, No. 4, pp. 286-292, 1967.

[5] C. H. Popenoe, M. S. Campbell, MIDAS modular interactive data

acquisition system - description and specifications, Nat. Bur. Stand.

(U.S.), Tech. Note 790, Aug. 1973.

[6] Interface Between Data Terminal Equipment and Data Communication

Equipment Employing Serial Binary Data Interchange, EIA RS-232-C.

Electronic Ind. Assoc., 2001 Eye St., N.W., Washington, D.C. 20006

Aug. 1969.

[7] IEEE Standard Modular Instrumentation and Digital Interface System

(CAMAC) - Computer Automated Measurement and Control , IEEE Stand.

583 - 1975, IEEE, 345 E. 47 Street, New York, NY 10017.

[8] American National Standard Code for Information Interchange,

ANSI X3.4 - 1977, Amer. Nat. Stand. Inst., Inc., 1430 Broadway,

New York, NY 10018.

[9] Ku, H. H., ed. Statistical Concepts and Procedures, Nat. Bur. Stand.

(U.S.), Spec. Pub. 300; 1, Feb. 1969, 436 p.

[10] Natrella, M. G., Experimental Statistics, Nat. Bur. Stand. (U.S.),

Handb. 91 , Aug. 1 963.

25
APPENDIX A

Hardware

Equipment lists, parts lists, and wiring diagrams of the equipment

used in the NBS Semiautomatic AC/DC Thermal Voltage Converter Calibration

System are contained in this appendix.

The use of trade names or company products does not constitute

endorsement or recommendation by the National Bureau of Standards, and

does not imply that the products named are necessarily the best available

for the purpose.

1 . List of Equipment.

1. Data Precision Model 5740 Frequency Meter.

2. Fluke Model 3330B Programmable DC Voltage Standard.

1 3. Hewlett-Packard Model 745A AC Voltage Standard, option HI 8.

4. Hewlett-Packard 746A High Voltage Amplifier.

5. Leeds & Northrup Model 9829D Digital Linear Amplifier.

6. Guildline Model 9577 Digital Voltmeter with BCD interface.

7. Data Precision Model 175 Digital Multimeter (2 ea).

2. Parts list for High Voltage Switching Module.

1. D1-D4: IN5620 diodes.

2. T1 : Rectifier transformer. Universal Rectifier Corp., model RT201

.

3. K1-K4: Relays. Magnecraft Electric Co., model W1 58HVX1 , SPOT,

DB-DM, 24 VDC. Rated 200 mA coil, 5 kV dc, 1 20 a coil.

4. SI, S2: CTS Rotary switch, series 212, #T205.

5. PI: Cable connector. Gen-Rad, type GR874-CA.

6. J1 : Panel connector. Gen-Rad, type GR874-PBA.

^For the frequency output connector of the ac calibrator, a triax BNC

to regular BNC adaptor is required. The adaptor used was made by

Trompeter Electronics, part number AD-PL76-E1 -81 20.

26
7. Pilot light. Industrial Devices, 215 0A1

.

8. J2-J4. BNC male panel mount connectors isolated from panel.

9. All resi stors 1 /4 W.

Parts list for Low-Thermal -Noise Switching Module.

1. K1-K5: Solenoids. Guardian Electric Co., pull type #24DC. Coil

voltage 24 V dc. 114 n coil resistance.

2. J1 : Panel jack. Amphenol #31 02A receptacle, #1 0S-02P insert.

3. PI: Cable plug. Amphenol #31 06B connector, #1 0S-02P insert.

#AN3057 cable clamp.

4. J2-J9: BNC male panel mount connectors isolated from panel.

5. P2: Cable plug. Amphenol #31 06B plug, #14S-05 insert, #AN3057-6

cable clamp.

6. SI: C.T.S. rotary switch, series 212, #T205.

7. All L.E.D.'s red, 5V, 16 mA.

Parts list for TE Comparator.

J1 & J2: Panel jack. Amphenol #31 02A receptacle, #10S-02P insert.

J3: Panel jack. Amphenol #31 02A receptacle, #1 4S-05P insert.

J4: Panel jack. Amphenol #31 02A receptacle, #10SL-03P insert.

Battery: Mallory Duracell RM42R 1.35 V.

Meter: 0-1 mA, DC.

R1 , R2: 10 a Gen-Rad #602-302.

R3: Beckman Helipot #SA 4391, 10 turn, 100 a, ±3%.

(Lindeck potentiometer fine adjust).

R4: 750 a, 10%, 1/2 W, carbon.

R5: Beckman Helipot #SA4912, 10 turn, 1 00 a , ±3%.

R6 , R7 : 100 a, ±10%, 1/2 W carbon.

R8 , R9 : 53k a, ± 10%, 1/4 W, carbon.

R10, Rll

:

1 a, ±1/2%, 1 W, precision pie wound.

27
R12: Precision pie wound, Ik n, ±1/2%, 1 W.

R13: Precision pie wound, 0.05 n , ±1/2%, 1 W.

R14: Beckman He! i pot #SA5427 , 1 0 turn, 1 00 n , ±3%.

(Kel vi n-'/arl ey divider fine adjustment).

R15: Gen-Rad #602-303, 100 a.

SI: Leeds & Northrup 12 position, 2 pole rotary selector switch

#031262. (Function switch).

S2: Leeds a Northrup 12 position, 3 pole rotary selector switch #031263.

(Kel vin-Varl ey divider coarse adjust).

S3: Leeds a Northrup 12 position, 6 pole rotary selector switch #031266.

(E-high or E-low selector switch).

S4: SPST bat handle toggle switch.

S5, S6: Set and read detector sensitivity switches. Leeds a Northrup

SPST #031187.

S7, S8: Set and read switches. Leeds a Northrup Guarded Low Thermal Key

switch DPST #031189.

S9: C.T.S. 7 position 2 pole rotary switch, series 212, #T205.

(Lindeck potentiometer coarse adjust).

28
High

Voltage

Switching

Module

Wire

Diagram

off

® 3a

_coQ< < £ <o

““ <5 n t—c

CO< — > £

oj «?

L
w-Thermal-Noise

Switching

Module

Wire

Diagram
NBS

Model

“BB”

TE

Comparator

.CAL

j

3

Output

to

the

LowS1

READ^R13

Thermal-Noise

Switching

Module

E

o

LL qj

31

Set

Read
Cable

Between

the

Low-Thermal-NoiseSA_

MM o

cz

k.

<3

CLEoO

<3

CL) 3

T3O

05C01

CO

32

145-05S,

AN

3057-6

Cable

Clamp
Midas

Equipment

List c3oQao

h-Eo>— LLCO

CO

H-Z

irT

II uCO<9 cc9

co

C*5

II X

HI

CM

HI

T”

II >3

co

a>w

'o

>, 5 a I

co

J

<u3o

CL

1/5 co a

a)c

"a coc 3 CO O Q

H3o

-i

OO

si ”

co

qa « o o

CC 00 CQ £ O t- N- 00 c3oaao

i-Eo—

u_n

II Oa

cvT

II O<

II CCoa

xf 905 9 o CO 05 3 O

CO

co > o 9 O > o a O CO 9 <

a)X9 o>

JC3 a

a. .£ U.

X

05r

r 05 05 3 X 9 9 5 CC CC c

><

_ca

Q

a o 9 O o

03 a: 03 CQ

05 o CM

CM CM CM

23

BCDI/O.DVM

24

System

Controller
APPENDIX B

ACDCHV Detailed Program Description and Program Listing

For ease of understanding the following detailed narrative program

description, the reader may find it useful to refer to the list of program

variables on page 40, and the program listing on page 44. Although not

included in this report, a detailed program flow chart is available upon

request.

The program begins by describing the software and appropriate reentry

points, as well as system limitations which would result in over-voltages.

Lines 20-108 are print statements which display the descriptive information

and warnings on the CRT. Statement 109, in which the program shunts

around a variable index (lines 110-1020) and a data header (lines 1030-1170),

is inserted when debugging, and deleted for formal testing when a heading

is desired on the printed data sheet. In statements 1180-1280, string

and array variables are dimensioned, and simple variables are initialized.

The statements in lines 1290-1310 generate, through a read command and a series of data statements (lines 1320-1400), a library containing

corrections to those TE standards that might be used during an ac/dc

difference test.

The constants stored in data lines 1320-1390 are those which are used to calculate the value of the standard TE's dimensionless characteristic

"n." Since n varies with applied voltage, its value can be related to the

TE's measured emf output, E (in mV). The value of n is assumed to vary

linearly with E. Thus, for example, for the standard "FI" in line 1320,

n is calculated as

n = 1.98 - 0.039E.

String variables used for instructions to MIDAS are then dimensioned and

defined (lines 1400-1420). Since instructions from, and data sent to,

MIDAS are done in real time, delay statements are used to handle timing

intervals between reception of programmed instructions and acquisition

of data. An upper limit for these delay statements is defined in statement

1430 concluding the system's software initialization.

A series of linked subroutines comprise the body of the program

which actually begins at line 1440. A print command causes the CRT to

beep, prompting the operator to enter, via the CRT keyboard, a test

voltage, test range, and standard TE range after a request for such test

requirements has been displayed (line 1450). A conditional statement in

line 1470 tests the status of flag S. S is set to 1 after an initial

test so that for any succeeding tests, the program jumps to subroutines

which turn off both dc and ac voltages, restoring each set of test

parameters when required (lines 5970-6050 for dc, and 6060-6160 for ac).

During a first run, however, S equals zero so the program falls through,

first to set the dc voltage, then to set the ac.

34
Both voltage-setting routines follow similar general formats.

Statements in lines 343Q-3990 set the ac voltage, while statements

4640-5190 set the dc. Before requesting voltage, range, and frequency

(ac only) parameters, instructions for coding these parameters are displayed on the CRT. Any variables which may yet be necessary are then established. These include temporary variables (such as F18, R18,

and V28 in ac, and R2 and VI 8 in dc), all of which are used to store

parameters when turning supplies on and off during high voltage tests.

Any flags for branching around certain instructions when testing at high

voltages are also included here; for example, D in the ac routine (lines

3620-3650). Because the initial instructions to MIDAS differ, depending

on a preselected range, conditional statements determine program flow to one of several sets of separate commands. Each of these command sets

issues an initial instruction to MIDAS for a particular range before

going back to the voltage set subroutine for more generalized instructions

which send, through MIDAS, previously defined parameters. After MIDAS

has sent the commands to those instruments being programmed, the operator

is prompted, via the CRT, to check if each device has actually responded

correctly. Should the operator indicate that a response is incorrect,

the program recycles the subroutine to receive new instructions. If

operator response indicates that the instruments have responded correctly,

control is returned to statement 1520 of the main program.

After both dc (1500) and ac (1510) voltages have been set, instructions

are displayed telling the operator to select the E-high comparator input,

turn off the Lindeck potentiometer and the ground switch of the comparator

and set the voltmeter to its 10 mV range. A variable for the test

number is incremented, while both "dc" and a 1 ow-thermal -noi se (K2)

relay are closed. The operation of the high voltage relays, as well as those solenoids contained in the 1 ow-thermal -noi se switch module, is

accomplished by instructions contained in repeatedly-accessed subroutines

in lines 5690-5900. Next, the dc power supply is turned on to the

previously programmed voltage value (1610). Before the voltmeter is

read (1640), the program executes a time delay (1620-1630) to permit the

TE to reach thermal equilibrium. Statements 1641-1651 ask which standard

TE is being used and check through a data library for its correction.

This correction is used in each of two formulas, only one of which is

accessed, contingent upon whether the standard or the UUT is connected

to the E-high or E-low input of the comparator (1750-1770).

When E s > E^ the program variable K is computed as

X > E tn s = E t (M s

- N

S E S ),

and, when Et > E

s , K is computed as

K = E s n s = Es (Ms

- N S E S ),

where the subscripts t or s refer to the UUT or the standard TE,

respectively, and M and N are constants as defined in the program

35
variable list on page 40. These equations have been derived in [2].

The emf of the TE connected to the E-high input is read first by

the voltmeter, and its value displayed on the CRT. Should E-low have a greater emf output than the TE connected to the comparator's E-high

input, the operator is instructed to switch comparator connections,

the test is aborted (1655-1718), and the initialization process begun

again. If the standard and test TE's are properly connected to the

comparator, K is computed and printed on the data sheet along with voltage,

test range, standard TE range, and emf outputs for both the standard and

the UUT.

If the UUT's emf actually is E-high, the operator is prompted to

select the E-high input of the TE comparator (if E-test < E-high, the

input selector switch remains at the E-low position). The potentiometer

is turned on, the 10 yV range of the voltmeter selected, and the

potentiometer adjusted until the voltmeter indicates within ±500 n V. Instructions and prompts in the statements in lines 1830-1950 cue the

operator to execute these manual operations. Then relay K2 opens and

relay K1 closes (lines 1970-1 990). The operator is then instructed to

adjust the Kel vi n-Varley voltage divider (±100 nV), after which dc

voltage parameters are stored, and the dc standard turned off. Both

"dc" and K1 relays open now, while relay K2 closes. Column headings for

the data sheet are printed, and variables for statistical calculation

are initialized.

Appropriate frequency corrections are computed for the standard TE.

Statements 2220-2230 prompt the operator to define the test frequency,

and statements 2240-2320 use this frequency value to determine the

correction and truncate the computed correction to a whole number. Now

the "dc" relay closes, and the dc power supply is turned on to the

previously selected test voltage, at which point the K2 relay closes.

The operator is then directed to readjust the potentiometer, after which

the dc voltage and range values are stored, the power supply turned off,

and the "dc" relay opened. Then the "ac" relay closes and the ac power

supply is turned on, first at 105 volts and finally to the proper high

voltage. A time delay in lines 2480-2490 allows the ac supply to settle

and the TE to reach thermal equilibrium before transferring control to

an ac voltage check subroutine (4000-4630) that adjusts the ac voltage

so that the output of the test TE is within 1000 nanovolts of its output

with dc voltage applied. The subroutine branches, depending upon whether

the ac voltage is too high or too low. The ac voltage is adjusted to

provide nominally equal UUT output only with direct dc voltage applied,

and not when reversed dc is applied. Furthermore, this ac voltage

adjustment is made only once at the beginning of the measurement sequence

to obtain four determinations of ac/dc difference. Hence, it is possible,

for UUT's with large dc reversal differences, for second-order errors to

become significant. However, the multirange instrument and single range

thermal converters tested with this system did not possess large dc

reversal differences.

The system was intended to calibrate high-quality thermal converters.

Hence, additional balancing steps to eliminate uncertainties due to

large dc reversal difference (i.e., difference between the dc direct and

36
reverse voltages required for the same TE emf output of the UUT) were not

needed. For the worst case, using 2.0 and 1.6 as the two extremes of

the characteristic n which may occur for the standard and UUT TE's, it can be shown [4] that systematic uncertainties of less than one-fourth

the UUT's dc reversal difference will occur. Minor software changes can eliminate this systematic error if large reversal voltages are anticipated.

The changes would amount to adjusting the ac voltage for a TE output

equal to that when dc reversed voltage is applied to the test circuit.

The only penalty for such a change in the operating procedure would be

an increase in testing time of perhaps one or two minutes (for four

determinations of ac/dc difference).

There is also the possibility of a systematic uncertainty if the ac or dc voltage standards drift during a sequence of four determinations.

However, for the same extremes of n, the uncertainty is only 10 ppm if

either source drifts by as much as 100 ppm. The STABLV and STABHY

programs readily provide information about the stabilities of the sources.

Once the ac voltage has been adjusted for about equal TE output as when dc is applied, relay K2 opens and relay K1 closes (2510-2540).

Cautions are displayed on the CRT to allow the voltmeter to stop drifting

before rebalancing the divider, should that be necessary. Statements in

lines 2600-2610 generate a time delay before the program jumps to test

the 10 voltmeter readings (5500-5650) to determine if the standard

deviation of an observation of 10 readings is < 200 nV. The test routine

allows for up to five reading sequences to be obtained before the test is

aborted and a suitable warning displayed on the CRT.

AC/DC difference is reported on the basis of the average of four

determinations. Each determination is calculated from the voltage

measurements with ac, dc+, dc-, and ac voltages applied simultaneously

in this sequence to the standard and test TE's. The last ac reading of one determination becomes the first ac reading of the next determination.

Each reading is taken by closing the appropriate relays, bringing up the

power supplies to previously programmed values, displaying the reading

in nanovolts, then storing the voltage parameters, powering down, and

opening the relays. This measurement process is accomplished by means

of statements in lines 2650-3050 and concludes the midsection of the

program.

The final section of the program computes statistical parameters,

formats the final output, generates a copy of the test data, and provides

measurement options to the operator. Statements 3060-3130 calculate the

mean of the four determinations and the standard deviation of an observation

in ppm, while statements 3140-3150 format the printed data, and tne

statement in line 3160 causes the data to be printed. Should the operator

wish to run another test, variables used to determine a pooled standard

deviation are then incremented in lines 3170-3230. Finally, options are displayed (3240-3250) asking whetner to repeat a test with or without

averaging, to change parameters, or to terminate. Since ac was the last

measurement to be taken, its voltage is turned off, although the ac

37
parameters are automatically stored for potential reruns (3275).

Statements 3280-3350 transfer program control to the operator-sel ected

option. If the operator has chosen to repeat a test without averaging,

lines 3380-3410 delete the pooled standard deviation data.

The standard deviation of an observation printed on the data sheet

is calculated for the four determinations of ac/dc difference at a fixed

voltage and frequency from the following:

p (Standard deviation) = (Variance), and the

n

k

£ <*i

-

,,

• i=l Variance = i

5

where, is the number of determinations at a fixed

voltage and frequency; i.e., the number of readings in test k = n^.

The final statistics which are printed on the data sheet are calculated

using the variables

H = total number of readings,

L = Number of independent tests,

D1 = Degrees of freedom = H-L,

S2 = Pooled estimate of the test standard deviation of

the mean = standard deviation of the test (SDT).

38
An estimate of the total random uncertainty is calculated as three

times the SDT and this product is therefore an estimate of the average

3a value for the test, and is calculated as

3a = (n-t) (n/t)

where, the degrees of freedom = n-t,

total number of readings = n =

k=l

number of independent tests = t.

These concepts are discussed fully in [9], pp. 316, ff.

39
ACDCHV PROGRAM VARIABLES

Note: 0

Vari abl

e

Name

A

Ad

A2

A4

A5

A6

B

B0

B1

B$

C

C7

C$

C0$

D

D1

D$

zero and not letter "oh"

Definition

Voltage applied to test and standard TE.

Array used to store the four determinations of ac/dc difference.

Variable in the subroutine used to increase or decrease

the ac voltage when driving the UUT's output to within

1000 nV of its value with dc voltage applied.

Variable which is input by the operator after verifying the

dc voltage (0 or 1 ).

Variable which is input by the operator after verifying

the ac voltage and frequency (0 or 1).

Variable which is input by the operator after determining

whether or not to change the frequency after the ac voltage

is set.

Voltage range of test TE.

Average of all determinations at one voltage and frequency.

Average of the four latest determinations of the test. B1 is used in the computation of the standard deviation of the

test.

Array used to store the data related to a particular TE.

Frequency correction to standard TE which is calculated by

using test frequency (P).

Variable used to increment or decrement the ac voltage to

drive the UUT's output to within 1000 nV of its value with

di rect dc applied.

String containing name of standard TE.

Variable used in input string to dc source to set range,

polarity, remote trip, and voltage trip range.

Flag to initially turn on ac supply at 105 V, and then

return and set the correct voltage and range.

Variable used for degrees of freedom in statistical

calculations. Dl = H-L.

String used to input date.

40
Variable

Name

E

E9

E1-E4

F0$

FI $

G

H

I

10

1$

18

19

J

J1

K

Kf)

Definition

E-high voltage reading, in mV.

E-low voltage reading, in mV.

DLA voltage difference readings with ac, +dc, -dc, and ac voltages applied to the standard and UUT TE's.

Used to input frequency to the ac source.

Storage variable for the ac source frequency used in the

ac voltage setting routine.

Dummy variable.

Total number of determinations of ac/dc difference per

test run.

Variable defining a for/next loop in which the standard TE

code file is established.

Variable used to designate the first element in array A

(the test voltage) when defining the variables M and N. Also used to define El = near-null voltage reading with ac applied, E2 = reading with +dc, E3 = reading with -dc,

E4 = reading with ac.

String used to input the test instrument manufacturer

,

name, and model number.

Variable used to define the for/next time interval loop.

Variable used to define the for/next "wait" timing loop;

e.g., to allow the dc or ac supplies to settle, or to

allow time for a TE to reach thermal equilibrium.

Flag for abort and total reset.

Variable used to define for/next loop in which X6 is computed.

J1 is used in the pooled estimate of the test standard

deviation of the mean.

Result of the standard TE's emf multiplied by the TE

character!

- sti c n

s when Es < E^, or the test TE's emf times

n s when E s > E^.

Variable used to define a for/next loop in which the ten

DLA near-null voltage readings are obtained, and then calculate

the standard deviation of the ten readings.

41
Vari able

Name

L

M

M0

R1

R2$

R05

R$

R1 $

S

51

52

T

T0

T$

V$

vo$

VI $

V2$

V

Defi nition

Number of independent tests for a complete test run; i.e.,

for all voltages and frequencies.

One of two constants used in the calculation of n

s

. The

other constant is N.

Variable used to implement MIDAS calls. M0 is the computer's

PASLA channel number in decimal.

Variable used to set the range of the dc supply.

Variable used to store the range of the dc supply before

turning it off.

Variable used to select the range for the ac supply.

Character string reference used for relay operation.

Variable used to store the range of the ac supply before

turning it off.

Flag for initial dc and ac voltage ranges.

Standard deviation of an observation for four or more

determinations of ac/dc difference at one voltage and

frequency.

Pooled estimate of the test standard deviation of the mean.

Decision point variable.

Time delay variable.

Output format string.

MIDAS input string.

String used to set voltages on both ac and dc supplies.

Variable used to store the dc voltage value in the dc

voltage setting routine.

Variable used to store the ac voltage value in the ac voltage setting routine.

Numeric value of V$. V is the value of the voltage

readi ng.

42
Vari abl e Name Definition

w Divisor used in the calculation of the mean of four or more

determinations at one voltage and frequency.

X, XI ,X2 All used in the standard deviation of the test (SDT).

calculation

.

X5,X6,X7 Used in calculating the pooled estimate of the standard

deviation of the mean.

Y Intermediate variable used in calculating Y1

.

Y1 Standard deviation of ten voltmeter readings.

Z Counter in the five standard deviation abort subroutine.

43
ACDCHV PROGRAM LISTING

20

30

40

50

60

70

80

90

95

96

97

98

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

120

130

140

145

150

160

1 70

180

190

195

200

210

220

224

226

230

240

;*PROG*

;*PROG*

NAME=ACDCH7

TESTS AC-DC

PROGRAM CONTAINS

HI* V* AMP* (AC) A

THIS PROGRAM HAS

INITIALLY AT 105

PROG* CAN BE USED

DIFF* AT HI 70 1 007,‘RANGE* 1 0 00 )*

SUBROUTINE CS) FOR TURNING ON A OFF*

FLUKE (DC , DCR ) WHEN SWITCHING RELAYS'

AUTOMATIC CONTINGENCY FOR TURNING ON

70LTS*

AT BOTH LO* A HI* 70LTAGES*

HI* 7* AMP*

TO RESET, RUN 5 9 1 0 * TO MAKE DEC IS ION (S

)

AFTER INITIAL RUN, RUN 3240*

CAUTION*

J" READ THIS CAREFULLY!*

;* FLUKE ALWAYS USES 1 K7 RANGE! HENCE, FOR LO 70LTAGE TESTS*

i* TO PRE7ENT DC 07ER70LTAGE, USE PRECEEDING ZEROES FOR CORRECT

J*EG* 97 ON 1K7 RAN GE*0 0 90 0 00 , AND 907 ON 1 K7 RANGE* 0 90 00 0 0*

; "MAKE SURE HP HI-70LT* AMP* IS ON*

;*TIME DELAY TO SET IN LINE 1430*

;

7'

GOTO

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM

REM ' REM

REM

1180

INDEX

THIS PROG* USES THE FOLLOWING 7ARIABLES

A, A0 ,A2,A4,A5,B,B0 ,B1,3S,C,C7,CS,C0S,

D,D1 ,DS,E,E1 ,E2,E3,E4,E9,F0S,F1S,G,H,

I, 10, 18, 19, IS , J, J1 , K, K0 , L, M, M0 ,M1 , M2 , N,NS,0,OS,02S,P,PO,R,RO,R1 ,R2,RS ,R0S ,Rl S

,

S,S1 ,S2,T,TQ,TS,7,7S,70S,71S,72S,W,

X,X1 , X2,X5,X6,X7,Y,Y1 ,Z

PRG* LINES 110-1020: PROGRAM INDEX A DEF. OF 7ARIA3LES

1030-1170

1180-1460

1470

1480

1490

1530-2320

2330-2570

2590-3050

2940-2950

3060-3230

3240-3410

3420-3990

3600

3730-3740

4000-4630

TEST DATA HEADING PRINTOUT

INITIALIZATION OF DATA

CONDITIONAL FOR RANGE CHANGE

CALL TO DC 70LTAGE SET SUB*

CALL TO AC 70LTAGE SET SUB*

EH A EL READINGS A 7ARIABLE INPUTS

AC 70LTAGE APPLIED

AC-DC -DCR READINGS

SAFETY MEAS* - CLOSE READ IN CASE OPEN

DATA PRINT A STATIS* CALCSEND OF TEST DECISION POINT

AC 70LTAGE SET ROUTINE

INITIAL STORAGE OF AC FREQUENCY

INITIAL STORAGE OF AC PARAMETERS

AC CHECK ROUTINE (DRI7ES AC WITHIN

100 NAN070LTS OF DC)

44
241 REM

242 REM

243 REM

250 REM

2S5 REM

260 REM

270 REM

280 REM

290 REM

300 REM

310 REM

312 REM

314 REM

316 REM

318 REM

320 REM

330 REM

340 REM

350 REM

360 REM

370 REM

380 REM

390 REM

400 REM

410 REM

420 REM

430 REM

440 REM

450 REM

460 REM

470 REM

480 REM

490 REM

500 REM

510 REM

520 REM

530 REM

540 REM

550 REM

560 REM

570 REM

580 REM

590 REM

600 REM

610 REM

612 REM

614 REM

616 REM

618 REM

620 REM

630 REM

631 REM

640 REM

650 REM

651 REM

660 REM

661 REM

NOTE: TO CHANGE NULL RANGE - LINE 40 80

TO CHANGE INCREMENT - LINES 4150 4 4400 FOR L«V.

FOR H.V. INCREMENT - LINES 4170 4 4420 ' * 4640-5190 : DC 'VOLTAGE SET ROUTINE

4760-4770: INITIAL STORAGE OF DC PARAMETERS

5200-5390: STATIS. PRINT ROUTINE FOR POOLED S-D.

5400-5490: DLA READ ROUTINE * * 5500-5680: STD. DEV. TEST (OF DLA READINGS)

5690-5790 : E-MOD. RELAY SET ROUTINE CHI. V. SV. ) 580 0-5 90 0 : K-MOD.' RELAY SET ROUTINE CLO*' THER. "SV. )

5910-6640: RESET; TURN-OFF 4 TURN-ON SUBROUTINE

5950-6050: TURN-OFF FLUKE 4 REDEFINE DC PARAM.

6060-6160: TURN-OFF HI. V. AMP. A REDEFINE AC PARAM.

6170-6330: TURN-ON FLUKE A RESTORE DC PARAM.

6340-6630: TURN-ON HI. V. AMP. A RESTORE DC PARAM.

RUN 3360: TO CHANGE RANGE

1510: TO CHANGE FREQUENCY

2330: TO REPEAT TEST

3290: TO RESET RELAYS ONLY

3380: TO TO REPEAT V/O AVE.

5200: TO GET POOLED S*D. STATIS. PRINTOUT

. 5910: TO ABORT A RESET ALL RELAYS

A*VOLTAGE APPLIED TO STANDARD TE.

A0 “ARRAY USED TO STORE THE 4 DETERMINATIONS.

A2* INCREMENTED IN AC VOLTAGE CHECK ROUTINE

* 3= RANGE OF TEST TE

B0 *AVE« OF ALL RDGS* OF A PARTICULAR TEST.

Bl-AVE.' OF ONLY 4 LATEST READINGS*

BS “ARRAY USED TO STORE EACH TE 'S CONSTANTS.

C“STD. TE FREQ. CORR. DETERMINED FROM INPUT FREQ*P

C7-VOLTAGE INCREMENT 'IN AC BALANCE ROUT.

C$=STRING CONTAINING I.D. OF STD. TE

C 0 S*USED IN INPUT STRING ’TO DC SOURCE

D=COUNTER FOR INITIAL INPUT (105 V) FOR HI . V. AMP. (AC

)

D1 “DEGREES . OF FREEDOM* H-L

” ' DS* STRING USED TO INPUT DATE

E*E-HI GH MILLIVOLT READING (EH)

E9*E-LOV MILLIVOLT READING (EL)

El TO E4* ALTERNATING AC-DC-DCR-AC NULL READINGS

F0 S*USED TO INPUT FREQ. TO AC SOURCE

G* DUMMY VARIABLE

H*TOTAL NO. OF DETERMINATIONS PER RUN

IS“STRIN G USED TO INPUT TEST INSTRUMENT MFG • 4 MODEL NO*

J*COUNTER FOR ABORT 4 TOTAL RESET

K= PRODUCT RESULT OF STD. EMF*STD.

TE CHARACTERISTIC (N* LOVER CASE I VHEN ES<ET

OR TEST EMF*STD TE CHARACTERISTIC

(N j LOVER CASE) VHEN ES>ET

L-TOTAL NO. OF TESTS PER RUN

M=CON STANT 'USED TO DETERMINE STD. TE

CHARACTERISTIC N-SUBSCRIPT S (N, LOVER CASE)

M0* IN MIDAS CALL IS THE PASLA CHANNEL NO- IN DEC.

M 1 “MAX. LENGTH OR TERMINATING CHAR.

OF MIDAS INPUT STRING

M2«STATUS VARIABLE SET AFTER

EACH MIDAS CALL - - - -- -

45
680 REM NS-STRING USED TO INPUT OPERATOR'S NAMeJ

690 REM OS* INPUT STRING SPECIFYING PHYSICAL &DDRESS

700 REM 02S*STRING USED TO INPUT TEST NO.

710 REM P-FREQUENCY INPUT (KHZ)

720 REM R*RANGE OF STD. TE

730 REM R0-VARIABLE SELECTS RELAY OPERATION

740 REM HV RELAYS. E-MODULE. R0-1.. CLOSE DCR RELAY

750 REM R0*2. .CLOSE AC RELAY

760 REM R0- 3.'.'CLOSE DC RELAY

770 REM R0*ir.'.OPEN DCR RELAY

780 REM R0- 12.'.'OPEN AC RELAY

790 REM R0* 13.'.'OPEN DC RELAY

800 REM K-MODULE. RQ-3* CLOSE EH. R0*2* CLOSE EL RELAY.

810 REM R0*4.. CLOSE SET RELAY

82 0 REM R0 *5.'.'CLOSE READ RELAY

830 REM R0*13; OPEN EH. R0-12, OPEN EL RELAY.

840 REM R0* 1 4 • .OPEN SET RELAY

850 REM R0* 15.'.'OPEN READ RELAY

860 REM R0*0 . '.'OPEN ALL RELAYS

870 REM R0S*RANGE SELECT FOR AC SOURCE

880 REM RS-CHARACTER STRING REFERENCE USED FOR RELAY OPERATION

890 REM S-COUNTER FOR RANGE

900 REM S1*STD. DEV. OF AN OBS. FOR

901 REM 4 OR MORE DETERMINATIONS

910 REM S2-P00LED EST. OF TEST S.D. OF MEAN

920 REM T*DECISION POINT VARIABLE

'* 930 REM T0*T IME DELAY LOOP VARIABLE

940 REM TS*OUTPUT FORMAT

950 REM VS-STRING OUTPUT FROM MIDAS

960 REM V0S*5TRING INPUT TO SET VOLTAGE

961 REM ON BOTH AC & DC SOURCES

970 REM V-NUMERIC VALUE OF VS

980 REM V*D IV ISOR IN AVE. CALC.

990 REM X* XI * X2* X5 * X6* X7*"ALL USED IN S.D.T.

1000 REM Y*USED IN Y1 CALC.

1010 REM Yi *STD. DEV. OF 10 DLA READINGS

1020 REM Z*COUNTER OF Yl 'S Z*5»A30RT

1030 DIM O2S(6)*IS(20>sDS(15)*NS(25)

1040 J" INPUT CURRENT DATE* YOUR NAME*TEST NO. * AND TEST INST."

1050 ;•

1060 INPUT DS*NS*02S* IS

1070 J ON C

6

) "DATE "*DS

1080 ; ON C6>

1 090 ; ON ( 6 ) "OBSERVER "*NS

1100 ; ON (6)

1110 ; ON <6 ) "TEST NO "*02S

1120 ; ON (6)

1130 ; ON (6)* INST "*IS

1140 ; ON (6 )

* * 1150 ; ON (6)

1160 ; ON (6)" APP TEST STANDARD ES ET

1170 ; ON <6)" V RANGE TE RANGE MV MV"

1180 DIM F0S(2)*F1S(2)*R0S(1)*R1S(1)*VQSC7)*VIS(7)*V2SC7)

1190 DIM C0S(3)sCS(2)«TS(72)j3S(7s8)sA(8s2)

X*

46
1200 S*Q

1210 J*0

1220 D*0

1230 MO *3

8

1240 Z*Q

1250 H«0

1260 L*0

1270 X7*Q

1280 V*0

1290 FOR 1*1 TO 8

1300 READ BSCI)*ACI*1 )*ACI*2>

1310 NEXT I 1320 DATA "Fi"*l.98*. 39E1

1330 DATA " F2 " * 2 • 0 3 * .2 8E1

1340 DATA * FG" *2. 04* .'3 1 E- 1 1350 DATA "FC"* 1

•* 9* • 32E1

1360 DATA "FH"*2.02*'.32£-i

1370 DATA "FA" *2.'Q3**'42E-1

1380 DATA "F3“* 1*94* •’ 14E-1

1390 DATA "FD"* 2* 03 *

42E1

1400 DIM VSC12>*0SC29>*RSC16>

1410 VS*"

1420 RS*"7?6>5*4<3;2: 1908"

1430 T0*1 80

0

1440 ;• " 1450 J" INPUT TEST VOLTAGE* TEST RANGE* STD. RANGE" . 1460 INPUT A*B*R

1470 IF S*G GOTO 1500

1480 GOSUB 5970

1490 GOSUB 6060

1500 GOSUB 4640

1510 GOSUB 3420

1520 ;" " 1530 ;"SET COMP. TO E-HIGH* POT #R OFF* DLA 10 MV* GND OFF"

1540 ;"TO CONTINUE* RETURN"

1550 INPUT G

1560 L*L+1

1570 R0*3

1580 GOSUB 5690

1590 R0 *4

1600 GOSUB 5800

1610 GOSUB 6170

1620 FOR 19*1 TO 1600

1630 NEXT 19

1640 GOSUB 5400

1641 J" INPUT THE CODE FOR STANDARD #TE *

C IN QUOTES )

1642 ;" " 1643 INPUT CS

1644 FOR 1*1 TO 8

1645 IF 3SCIX>CS THEN 1648

1646 10*1

1647 1*100

1648 NEXT I 1649 IF X>*100 THEN 1653

1650 ;• STANDARD NOT FOUND; TRY AGA IN"

1651 ;• • -
1652

1653

1654

1655

1660

1670

1680

1690

1700

1710

1712

1714

1716

1718

1720

173 0

1740

1750

1760

1770

1780

1790

1800

1810

1820

1830

1840

1850

1940

1950

1960

1970

1980

1990

2000

2010

2020

2030

2035

2040

2050

2060

20 70

2080

2090

2110

2120

2130

2140

2150

2160

2170

2180

2190

220 0

2210

GOTO 1641

M*A (10*1 ) N*A( 10 #2

)

E*V # l 000

i*E-HIGH - m *Z* "MILLIVOLTS"

J" CHANGE #BB * TO E-LOV* THEN RETURN * INPUT G

GOSUB 5400

E9»V*1 000

;*E-LOV *" jE9* "MILLIVOLTS*

IF E>E9 THEN 1720

- ;"E-LOV IS GREATER THAN E-HIGH, SWITCH CONNECTIONS*

GOTO 5910

TS^'IMMMMM.I •••*• •• Mt.t ••••

; ON (6)

' .. ..

;• * ;*if*;cs;*is e-hxgh, input *\ if not* input # o

# ."

INPUT G

IF G* 0 GOTO 1810

K»E9*CM-E*N>

; ON (6) USING TS>A.»B # C5^R^E^E9#K

GOTO 1940

K=E9*<M-E9*N>

; ON C 6 ) USING TS>A>B^CS>R>E9.»E^K

;* * J"SET COMPARATOR TO E-HIGH. RETURN"

INPUT G

J "POT 'R ON - SET DLA 10 MICRO-VOLTS - SET NULL^ RETURN

;* * INPUT G

R0 * 1

4

GOSUB 5800

R0-5

GOSUB 5800

^"BALANCE DIVIDER* THEN RETURN"

;*

INPUT G

GOSUB

R0 * 1 5

5970

GOSUB

R0 * 1 3

5800

GOSUB

R0*4

5690

GOSUB 5800

; on (6)

; on (6)* KHZ COR

; on < 6

) " STD AVE T

; on <6>" PPM

; on ( 6

) "DEV COR PPM

; on

X-0

X1»Q

(6)

X2*0

C*0

V=* 0

AC -DC DIFFERENCE

*

48
2220

2230

2240

2250

2260

2270

2280

2290

2300

2310

2320

2330

2340

2350

2360

2370

2380

2390

2400

241 0 2420

2430

2440

2445

245 0

2460

2470

2480

2490

250 0 2510

2520

2530

2540

2550

2560

25 70

2580

2590

2600

2610

2620

2630

2640

265 0

2660

2670

2680

2690

2700

2710

2720

2730

2740

275 0

J * INPUT" FREQUENCY C KHZ )

;•

INPUT P

IF R< 1 0 0 THEN C*0

IF R* 100 THEN C*-CP*2/1 0 00

)

IF R=200 THEN C* - <P*2/ 1 0 0 0

)

IF R-300 THEN C* CP"2/1 0 0 0

) * 1 .

5

IF R-60 0 THEN C* CP*2/1 000 >* 1 -3

IF R=1001 THEN C* CP* 2/ l 0 0

> *2-P

IF Ra 1002 THEN C*P*2*.12E-1

C* INT CC ) R0*3

T*3

GOSUB 5690

GOSUB 6170

" R0 *4

GOSUB 5800

J" SET POT NULL# THEN RETURN"

INPUT G

GOSUB 5970

R0 = 1 3

GOSUB 5690

GOSUB 6060

R0 =2

GOSUB 5690

GOSUB 6340

FOR 19* 1 TO 2000

NEXT 19

GOSUB 4000

R0* 1

4

GOSUB 5800

R0*5

GOSUB 5800

IF V<>0 THEN 2600

;*VAIT FOR DLA TO STOP DRIFT.*

; "REBALANCE DIVIDER IF NECESSARY#

INPUT G

FOR 19*1 TO TO

NEXT 19

GOSUB 5500

E1*V*. 1 El 0 ;*E1 ‘ *"#E1# "NANOVOLTS*

FOR 10=1 TO 4

GOSUB 6060

R0 * 1 2

GOSU3 5690

RQ*3

GOSUB 5690

GOSUB 6170

FOR 19*1 TO TO

NEXT 19 , GOSUB 55JJJU

E2*V*. 1E10

THEN RETURN."

49
2760 ;"E2 ‘ -"^E2> “NANOVOLTS"

2770 GOSUB 5970

2780 R0 * 1

3

2790 GOSUB 5690

2800 R0-1

2810 GOSUB 5690

2820 GOSUB 6170

2830 FOR 19-1 TO TO

2840 NEXT 19

2850 GOSUB 5500

2860 E3»V*.1E10

2870 ;*E3 ' *

- *E3* "NANOVOLTS"

2880 GOSUB 5970

2890 R0*11

2900 GOSUB 5690

2910 R0 *2

2920 GOSUB 5690

2930 GOSUB 6340

2940 R0 *5

2950 GOSUB 5800

2960 FOR J9*l TO TO

2970 NEXT 19

2980 GOSUB 5500

2990 E4*V*.1E10

3000 ;”E4 '* *",E4«*"N(AN0V0LTS"

q 0 1 0 A0 < 10 )=C-E1 E2*E3-E4)/<2*K)

3020 IF 10*4 THEN 3050

3030 El *E4

3040 ;“E1 *",EW "NANOVOLTS"

3050 NEXT 10

3060 V»V+4

30 70 X=X+A0 < 1 )"2+A0 (2 )~2+A0 (3 )"2+A0 C4)"2

30 80 X1=X1 +A0 <1 ) +A0 C2)+A0 C3)+A0 <4>

3090 B1*A0 <1 >+A0 C2)+A0 C3)+A0 <4)

3100 Bl*Bl/4

3110 B0*X1/V

3115 P0*CX1/V)*KC>

3120 X2 fi 30 *X1

3130 S1»SQRC CX-X2)/(V-1 ))

3140 T$C1*5Q)«"»0«. M- -ft ( -# § f 9 -9999 -9999 -9099 ) 3150 TSC5W72)*" '•##.§ -«««••• " 3160 J ON C 6 ) USING TSjP*C*A 0 Cl )>A0 <2 ) ^ A0 (3 ) AO C4)*S1>P0

3170 Hs H+4

3180 X6*

0

3190 FOR Jl=l TO 4

3200 X5 = C A0 CJ1 )-Bl ) ~ 2

3210 X6=X6+X5

3220 NEXT J1

3230 X7-X7+X6

3240 J " REPEAT .» FREQUENCY* RANGE* STOP > REPEAT V/O AVE. 7"

3250 ;* 1 2 34 5

" 3260 ;• “ 3270 INPUT T

3275 GOSUB 6060

3280 IF T-4 THEN 5200

50
3290 Ml *0

3300 0S*"<35>E89: ;<a>?K89: ;<*>?"

3310 CALL 1 *MO*OS*VS*M1 *M2

3320 IF T* 1 THEN 2330

3330 IF T*2 THEN 1510

3340 IF T*3 THEN 3360

3350 IF T*5 THEN 3380

3360 S*1

3370 GOTO 1450

3380 X7=X7-X6

3390 H*H-4

340 0 ; ON C 6

) “ABOVE DATA DELETED FROM TEST*

3410 GOTO 2160

3420 GOSUB 6060

3430 ; 3440 ;* AC VOLTAGE SET

3450 J********* IMPORTANT NOTE  ** **••-*• 3460 * " WHEN SETTING AN AC VOLTAGE OF i*10*OR 100 VOLTS* YOU MUST*

3470 J“CHOOSE THE MAX. OUTPUT OF THE CORRESPONDING RANGE* FOR EXAMPLE*

3480 * * VHEN APPLYING 10 V YOU MUST PROGRAM 5-NINES (99999) ON THE 10 V*

3490 ;*RAN GE* AND NOT (REPEAT NOT) 1 00 00 ON THE 100 V RANGE*

3500 ; 3510 ; 3520 ;*THE FREQUENCY IS CODED IN TVO DIGITS. THE FIRST DIGIT MUST BE*

3530 ;*A NUMBER FROM 1 TO 11* MEANING THE HIGH ORDER DIGIT. THE*

3540 ** SECOND DIGIT ARE MULTIPLES OF 10* STARTING WITH 0*X1'Q AND*

3550 ;*3 ® XI 0 K. IN HEX- A TEN IS A'j' AND A ELEVEN IS A';'.*

3560 ; 3570 ;* * 3580 i* INPUT FREQUENCY3590 INPUT F0S

3600 F1$*F0S

3610 1 3620 D»1

3630 ROSa-6*

3640 GOSUB 6420

3650 D*0

3660 ;*TO SET VOLTAGE AND RANGE* FIRST INPUT THE CORRECT RANGE3670 ** FOLLOWED BY THE 5-DIGIT VOLTAGE. A RANGE OF 0 * 1MV* 1 * 1QMV*"

3680 ;*2 * 100MV * 3 * IV * 4 « 1 0V * 5 - 100V * AND 6 * 1000V."

3682 1* VHEN TEST LO A HI AC MUST SET RANGE TO NEXT3684 ;* HIGHEST RAN GE LIMIT FROM TEST VOLTAGE3686 ;* (EX. 1 - TEST 4 V AC SET RANGE AT 4=10V OR*

3688 ;* EX. '2 - TEST 100 V AC SET RANGE AT 6*1000).*

3690 ; 3700 ;* * 3710 ;* INPUT RANGE* VOLTAGE3720 INPUT RQS*V0S

3730 RISaROS

3740 V2S* VO S

3750 IF R0S**6* GOTO 3820

3760 OS«*<35>C?"+V0S(l*5)+RQS+F0S+"02"

3770 CALL 1 *M0 *OS*VS*Ml *M2

3780 Ml * 1 3790 OS*"<3S>rO*
3800 CALL 1 *MO*OS*VS*M1 *M2

3810 GOTO 3880

3820 OS**<35>CP*+VOS C 1 * 5 ) +R0S +F0S +*2 0 * 3830 ; 3840 ^"CONNECT HIGH VOLTAGE AMP* * THEN RETURN*

3850 ;* * 3860 INPUT G

3870 GOTO 3770

3880 CHECK AC. VOLTAGE AND FREQUENCY* I F CORRECT INPUT '1 # ** 3890 J "THEN RETURN. IF INCORRECT* INPUT * 2

* *THEN RETURN.*

3900 i* * 3910 INPUT A5

3920 IF A5-1 GOTO 3940

3930 GOTO 3420

3940 i*IF FREQ. CHANGE INPUT #

1 * * IF RANGE OR INITIAL RUN * RETURN*

3950 ;*

3960 INPUT A6

3970 IF A6* 1 GOTO 2160

3980 IF R0S*"6* GOTO 6060

3990 RETURN

4000 ;*AC VOLTAGE CHECK*

4010 RQ*2

4020 GOSUB 5690

4030 GOSUB 5400

4040 JV . 4050 A2*V

4060 A2*A2*.1E9

4070 V=V*. 1 E9

4080 IF A3SCA2X10Q THEN 4600

4090 IF VS ( 1 * 1 ) = *-• THEN 4350

4100 IF R0S**4* THEN 4140

4110 IF R0$a*5* THEN 4140

4120 IF R0S** 6" THEN 41401

4130 GOTO 4150

4140 IF VOS (1*1 )**9* THEN 4170

4150 C7a 3

4160 GOTO 4180

4170 C 7*40

4180 A2*VAL(V0S)

4190 A2*A2-C7

420 0 V0 S*STRS <A2 ) 4210 Ml *0

4220 IF R0S«"6* GOTO 4290

423 0 OS*“<35>CP*+V0S ( 1 * 5 ) +R0S FO S

* 0 2*

4240 CALL l*M0*OS*VS*Ml *M2

4250 Ml a 1 4260 OS** <35>F0

4270 CALL 1*MO*OS*VS*M1*M2

4280 GOTO 4310

4290 OS**<35>CP*+V0S U *5 ) +R0S +F0S +"20*

4300 GOTO 4270

4310 FOR 18*1 TO 1500

4320 NEXT 18

4330 GOSUB 5400 -

4340 GOTO 4040

52
4350 IF RQS*"4* THEN 4390

4360 IF R0S*"5" THEN 4390

4370 IF R0S*"6" THEN 4390

4380 GOTO 4400

4390 IF V0S<1#1>*"9" THEN 4420

4400 C7*3

4410 GOTO 4430

4420 C7-40

4430 A2*VAL(VQS>

4440 A2-A2+C7

4450 VQS*STRSCA2>

4460 Ml *0

4470 IF R0S*"6" GOTO 4540

4480 OS*"<35>CP" VO SCl#5)+R0S+F0S+"02"

4490 CALL 1 #M0#O$#VS#Ml #M2

4500 Ml *

l

4510 OS*"<35>F0

4520 CALL 1 #MO#OS#VS#M1 #M2

4530 GOTO 4560

4540 OS*"<35>CP"+V0S Cl#5)+RQS+FQS+"20"

4550 GOTO 4520

4560 FOR 18*1 TO 1500

4570 NEXT 18

4580 GOSUB 5400

4590 GOTO 4040

4600 R0 *2

4610 V*V/.1E9

4620 GOSUB 5690

4630 RETURN

4640 ;• DC VOLTAGE SET " 4650 VS*"

4660 ; 4670 ;"TO SET THE VOLTAGE RANGE AND TRIP# INPUT FIRST THE CORRECT"

4680 i"RANGE FOLLOWED BY A COMMA AND THE DESIRED VOLTAGE. RANGES"

4690 ;"OF 10# 100# AND 1000 ARE ALLOWED. VOLTAGE MUST BE 7 DIGITS."

4695 ;" WHEN TEST AT LO V C<*100 V DC ) MUST SET RANGE AT 1000."

4700 ; 4710 ;• INPUT RANGE# VOLTAGE"

4720 ;•

4730 M0*38

4740 Ml *0

4750 INPUT R1 # VOS

4760 R2*R1

4770 VlS*V0S

4780 IF Rl-10 GOTO 4990

4790 IF R1-1QQ GOTO 5030

4800 IF R1 * 1 0 0 0 GOTO 5070

4810 GOTO 4710

4820 OS*"<35>DP"+V0S+"j;"^C0S

4830 CALL 1 #M0 # OS # VS#M 1 #M2

4340 Ml * 1 4850 05*"<35>FQ"

4860 CALL 1 #M0

#

OS # VS#M1 # M2

4870 VS C2#2 )** " 4880 ;vs

53
4890 IF VAL CVS ) <> 6 THEN 5110

4900 J" CHECK DC VOLTAGE* IF CORRECT INPUT M '* THEN RETURN."

4910 J" IF INCORRECT* INPUT *2 * * THEN RETURN4920 J4930 INPUT A4

4940 IF A4* 1 GOTO 4950

4945 IF A4*2 GOTO 5130

4950 GOTO 5970

4960 RETURN

4970 GOTO 4640

4980 RETURN

4990 C0S*"840"

5000 os*"<35»dpoooqooo;;"*m:os

5010 CALL 1 * M0 * 05 * VS* Ml *M2

5020 GOTO 4820

5030 COS*" 942"

5040 OS*"<35>DP0Q0000Q;;"*C0S

5050 CALL l*MQ*OS*VS*Ml *M2

5060 GOTO 4820

5070 CQ$*"*4l

5080 OS*"<35>DP0000Q00J;"+C0S

5090 CALL 1*MO*OS*VS*M1 *M2

5100 GOTO 4820

5110 J" WARN ING - SYSTEM TRIPPED* SUPPLY AUTOMATICALLY RESET5120 J* TRY AGAIN."

5130 Ml *0

5140 V0S*-0000000-

5150 C0S*"000"

5160 OS*"<35>DP"+V0S+"00"+C0S

5170 CALL 1*MO*OS*VS*M1*M2

5180 GOTO 4640

5190 RETURN

5200 ;"DO YOU WANT STATISTICS PRINTOUT?"

5210 ;*IF YES* ENTER *1 # AND RETURN5220 ;*IF NOT * ENTER '2 # AND RETURN5230 ;- “ 5240 INPUT T

5250 IF T*2 THEN 5910

5260 D1*H-L

5270 S2*SQRC (X7/D1 )/<H/L>

>

5280 J ON (6)

5290 J ON C 6

) "NUMBER OF READINGS*H* "*H

5300 ; ON (6)

5310 i ON < 6

) "NUMBER OF INDEP. TESTS*L*. . "*L

5320 J ON (6)

5330 ; ON (6 )"DEGREES OF FR£EDOM*Dl * "*D1

5340 ; ON <6)

5350 J ON <6 )*PQOLED ESTIMATE OF TEST STD. DEV. OF MEAN*S2"

5360 I ON (6)"*S.D.T. (SEE S.P. 300*V«1* P*' 31 6-40 >....*" *S2

5370 ; ON <6)

• • • 5380 ; ON <6)-3*S.D.T.« "*3*S2

5390 GOTO 5910

5400 Ml * 1

2

5410 0S*"<35>BTTU<1 7>_^ .

54
5420 CALL 1 #M0#OS#VS#Ml #M2

5430 VS (LEN (VS ) +1 # LEN (VS)+i)*“ * 5440 IF VS (2# 2 )*" : “ THEN 5480

5450 IF . VS (2# 2 ) *" * " THEN 5480

5460 V*VALCVS>

5470 RETURN

5480 V*20 0 0

5490 RETURN

5500 Y*

0

5510 Y1 *0

5520 FOR K0* l TO 10

5530 GOSUS 5400

5540 Y* Y+V . . 5550 Y1*Y1+V*V

5560 NEXT K0

5570 Yl*SQRCCYl-(Y# Y/iO))/9)

5530 IF Y1 *• IE1 0<20 0 THEN 5660

5590 J*STD. ‘DEV. **# Y1 *. IE 1 0 * "NANOVOLTS*

5600 Z*Z+1

* 5610 IF Z*5 THEN 5630

5620 GOTO 5500

5630 J " WARN IN G- JOB ABORTED# TESTS EQUAL FIVE# SYSTEM UNSTABLE"

5640 ;* * 5650 GOTO 5910

5660 V* Y/ 1

0

5670 Z*0

5680 RETURN

5690 R0 * INT CR0

)

5700 IF RQ>*0 AND R0<19 THEN 5730

5710 ;* INVALID RELAY ADDRESS*

5720 RETURN

5730 Ml *0

5740 R1 * INT (R0/ 10)

57S0 R2* INTCR0-R1*10>

5760 IF R0 <> 0 THEN OS** <35>E* +RS C2*R2-1+R1 # 2*R2 -1 +R1 ) 5770 IF R0*0 THEN 0S**<35>E89 i

J

<*>?*

5780 CALL 1 #M0 # OS #VS #M1 #M2

5790 RETURN

5800 R0 * INT CR0

)

5810 IF R0>*0 AND RQ<19 THEN 5840

5820 ;* INVALID RELAY ADDRESS*

5830 RETURN

5840 Ml *0

5850 R1 * INT (R0/ 1 0 ) 5860 R2* INT (R0-R1*1Q)

5870 IF R0 <> 0 THEN OS*" <35> K* +RS <2*R2- 1 +R1 # 2*R2 -1 +R1

)

5380 IF R0 * 0 THEN OS** <35 > K89 :,’<*> ?*

5890 CALL 1 #MO#OS#VS#M1 #M2

5900 RETURN

5910 R0 *

0

5940 J*1

5950 R0 *0

5960 Z*0

5970 Ml *0

55
5980 VOS*-OOOOQOO"

5990 C0S--000*

6000 OS*"<35>DP"*V0S+"00*«’C0S

6010 CALL l.»M0,OS,VS,Ml.,M2

6020 IF J?I GOTO 6080

6030 VQS*V1S

6040 R1*R2

6050 RETURN

6060 Ml *0

6070 V0s*"0000000*

6080 RQ S* “

0

6090 F0 S* * 0

0

610 0 OS*“<35>CP" ^VOS ( 1 # 5 ) +RQS +F0S "00*

6110 CALL l*MO#OS#VS.»Ml#M2

6114 GOSUB 5690

6120 IF J*1 GOTO 6640

6130 R0 $*R1

S

6140 V0S*V2S

6150 F0S*F1S

6160 RETURN

6170 MO *38

6180 Ml *0

6190 C0S*"*41

6200 OS*"<35>DPOOOOOOO;;"+COS

6210 CALL .1,MO,OS,VS,M1.,M2

6220 V0S*V1S

6230 R1 =R2

6240 FOR 19*1 TO 100

6250 NEXT 19

6260 OS*-<35>DP"+V0S+-;; ,, «-C0S

6270 CALL 1 ^MO^OS^VS^Ml ,M2

6280 Ml * 1 6290 OS = * <35> F0

6300 CALL l*M0*OS*V5*Ml *M2

6310 R2*Ri

6320 V1S*V0S

6330 RETURN

6340 Ml *0

6350 V0s*-Q000000*

6360 R0 S* "

0

6370 F0S*"Q 0"

6380 OS*"<35>CP"+VQS (1*5 > +R0S +FQS

0

0

6390 CALL 1 *M0 * OS * VS*M1 *M2

6400 R0S*R1S

6410 F0S*F1S

6420 VQS*“ 10500"

6430 FOR 19*1 TO 100

6440 NEXT 19

645 0 OS*-<35>CP*«-V0SC W5>*R0S+F0S+"2Q"

6460 CALL 1 *M0 * OS*VS*Ml *M2

6470 Ml * 1 6480 OS* " <35> F0

6490 CALL l*M0*OS*VS*Ml *M2

56
6500

6510

6520

6530

6540

655 0 6560

6570

6560

6590

660 0 6610

6620

6630

664 0

665 0

FOR 19-1 TO 150

NEXT 19

Ml *0

IF D-l GOTO 6630

V0S-V2S

0$="<35>CP"+VOS(1*5)+RO$+FQ$+"2Q"

CALL 1 >MO^OS/VS^M1 >M2

Ml -

1

OS*-<35>F0"

CALL 1#MOjOS>VSjM1sM2

F1S-F0S

R1S-R0S

V2S = V0_Sj

RETURN

GOSUB 5800

END

57

NBS-114A (rev. 9-78)

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 82-2576

2-Go^L Accession No.

4. TITLE AND SUBTITLE

A SEMIAUTOMATIC AC/DC THERMAL VOLTAGE CONVERTER

CALIBRATION SYSTEM

5. Publication Date September 1982

6. Performing Organization Code

7. AUTHOR(S)

K. J. Lentner and S. G. Tremaine

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, DC 20234

10. Project/Task/Work Unit No.

11. Contract/Grant No.

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, City, State, ZIP)

U.S. Department of Defense

Calibration Coordination Group

13. Type of Report & Period Covered Final

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

|

' Document describes a computer program; SF-185, FIPS Software Summary, is attached.

IS. ABSTRACT (A 200^word or less /actual summary of most significant information . If document includes a si gnificant bibliography or

literature survey, mention it here.)

A semiautomatic ac/dc difference calibration system is

described. The system operates over a frequency range of 20 Hz

to 100 kHz, covering the voltage range from 0.5 V to 1 kV. For

all voltages at frequencies in the range from 20 Hz to 20 kHz,

the total uncertainty is 50 parts per million (ppm), and 100 ppm

for voltages at frequencies between 20 kHz and 100 kHz. In addition to ac/dc difference testing, the system can be readily

adapted to calibrate precision ac digital voltmeters or ac calibrators. Results of extensive i ntercompari son testing of

the new system against a manual test system are reported, using

a multirange thermal transfer instrument as a transport standard.

The results indicate that the ac/dc differences measured are well

within the combined total uncertainty limits of the two systems.

17. KEY WORDS (six to twelve entries ; alphabetical order; capitalize only the first letter of the first key word unless a proper name

separated by semicolons)

ac/dc difference; ac voltage measurement; automation; calibration;

metrology; thermal voltage converter.

18. AVAILABILITY i Xr Unlimited

! ; For Official Distribution. Do Not Release to NTIS

j Order From Suo. of Doc., U.S. Government Printing Office, Washington, DC

20402, SD Stock No, SN003-003- PC Order From National Technical Information Service (NTIS), Springfield,

VA. 22161

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

21. NO. OF

PRINTED PAGES

62

22. Price

59.00

JSCOMM.-C