IS 8493 (1977): Analogue dc voltage signals for industrial process … · 2018-11-15 · IS : 8493 - 1977 Indian Standard ANALOGUE DC VOLTAGE SIGNALS FOR INDUSTRIAL PROCESS MEASUREMENT

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IS 8493 (1977): Analogue dc voltage signals for industrialprocess measurements and control systems [ETD 18:Industrial Process Measurement and Control]

IS:8493 -1977

Indian Standard ANALOGUE DC VOLTAGE SIGNALS

FOR INDUSTRIAL PROCESS MEASUREMENT AND CONTROL SYSTEMS

Electrical Instruments for Industrial Processes Sectional Committee, ETDC 53

Chairman

PROP ( DR ) J. K. CHOUDHURY Jadavpur University, Calcutta

Members Representing

SHRI J. S. AHLUWALIA Fertilizer Corporation of India Ltd, New Delhi DRY. 1,. ARORA Century Rayon, Bombay

SARI C. B. PUNDIT ( Alternatc ) $&RI I(. R. BANERJEE Instrumentation Ltd, Kota

SHRI C. S. DANC ( A&mate ) SHEI G. R. BHATIA Directorate General of Supplies & Disposals

SHRI J. S. Passr ( Alternate ) ( Inspection Wing ), New Delhi

SIIRI J. S. BRAT-IA Electronics Corporation of India Ltd, Hyderabad DR. N. SATYAZrARAYANA ( Alternate )

DR I-1. BHAUIIIIE SHRI V. K. BURSHI ( Alternate )

Institute of Paper Technology, Saharanpur

SHRI p. K. CHA~RAVORTY Indian Oil Corporation Ltd, New Delhi SRRI H. P. DEY

SHRI S. BISWAS ( Alternate ) Mahindra & Mahindra Ltd, Calcutta

COL R. C. DHI~-ERA Controllerate of Inspection ( of Defence ), Bangalore

Electronics ) ( Ministry

SHRI H. K. RAMAMURTIIY ( Alternate ) &RI R. N. GANDHI Institute for the Design of Electrical Measuring

SHRI N. VAKVARI ( Alternate ) Instruments, Bombay

SHRI A. K. GHOSA Hindustan Steel Limited, Ranchi S HRI B. P. GHOSH National Test House, Calcutta

SI~RI D. N. UPaDHYA ( Alternate ) S,rnr R. GoPAILAI(RISHNAN Engineers India Ltd, New Delhi

SHRI A. K. VERMA (Alternate )

( Continued on page 2 )

@ Copyright 1977 INDIAN STANDARDS INSTITUTION

Th& publication is prote.cted under the Indian Copyright Act ( XIV of 1957 ) and reproduction in whole or m part by any means except with written permission of the publisher shall be deemed IO be an infringement of copyright under the said Act.

IS : a493 - 1977

( Continued from page 1 )

Members Rejwesenting

SHRI B. P. MITAL Central Scientific Instruments Organization ( CSIR ), Chandigarh

SHRI K. G. P.4RJlW Millowners’ Association, Bombay SHRI B. S. PRARHAK_~R Department of Atomic Energy, Bombay

SHRI S. RAA~AKRIRRNAN ( Alternate 1 SHRI D. V..S. RAJU Eli& Pvt Ltd, Hyderabad

SHRI S. A. H. KHAN ( Alternate ) SHRI K. N. RADIABWAMY Directorate General of Technical Development,

New Delhi SRRI R. SOUNDHIRARAJAN ( Alternate )

SHRI N. N. SARKAR M. N. Dastur & Co ( Pvt ) Ltd, Calcutta SHARI N. G. CHATTOPADRYAY (Alternate )

SHRI p. s. SH_4RXA Metallurgical and Engineering Consultants

SRRI B. C. NA~R ( Alternate ) ( MECON ), Ranchi

SHRI S. P. SURI

DR T. K. SAXEN_ ( Ahernatc )

National Physical Laboratory ( CSIR ), New Delhi

DR G. R. TOSHNIWAL Toshniwal Industries Pvt Ltd, Ajmer SHRI S. C. MAHESHWARI ( Alternate )

SHRI S. P. SACHDEV, Director ( Elec tech )

Director General, ISI ( Ex-o&o Member )

Secratav

SHRI HARCHARAN SINQH Deputy Director ( Elec tech ), IS1

2

IS : 8493 - 1977

Indian Standard ANALOGUE DC VOLTAGE SIGNALS

FOR INDUSTRIAL PROCESS MEASUREMENT AND CONTROL SYSTEMS

0. FOREWORD

0.1 This Indian Standard was adopted by the Indian Standards Institution on 27 June 1977, after the draft finalized by the Electrical Instruments for Industrial Processes Sectional Committee had been approved by the Electrotechnical Division Council.

0.2 In the preparation of this standard, considerable assistance has been derived from Dot: 65A ( Central Office ) 5 ‘Draft - Analogue direct voltage signals for industrial processes measurement and control systems’ issued by the International Electrotechnical Commission.

0.3 For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test, shall be rounded off in accordance with IS : 2-1960*. The number ofsignificant places retained in the rounded off value should be the same as that of the specified value in this standard.

1. SCOPE

1.1 This standard specifies analogue dc voltage signals used in industrial process measurement and control systems to transmit information between the elements of systems.

NOTE - Contrary to the analogue dc current signals specified in IS : 7728-19751, the analogue dc voltage signals are not intended for transmission over long distances.

1.2 This standard does not apply to analogue dc voltage signals used entirely within an element.

2. TERMINOLOGY

2.0 For the purpose of this standard, the following definitions shall

apply.

*Rules for rounding off numerical values ( revised ). tAnalogue dc current signals for process control systems,

3

IS : 8493 - 1977

2.1 Elements of Industrial Process Measurement and Control Systems - Functional units, or integrated combinations thereof, which ensure the transducing, transmitting or processing of measured values, control quantities, control variables and reference variables.

2.2 Analogue dc Voltage Signal - A dc voltage signal used for transmission or processing which varies in a continuous manner according to one or several physical quantities.

2.3 Measured Value of an Analogue dc Voltage Signal - The mean value during a stated duration.

2.4 Range of an Analogue dc Voltage Signal - The range dctermi- ned by the lox,Yer limit and the upper limit of the signal voltage.

2.5 Lower Limit - The signal voltage corresponding to the minimum value of the dc voltage signal.

2.6 Upper Limit - The signal voltage corresponding to the maximum value of the dc voltage signal.

2.7 Load Impedance - The resultant of the impedances of all connec- ted receivers and connection lines.

2.8 Ripple Content - The ratio between the peak-to-peak value of the alternating component and the upper limit of the voltage signal.

2.9 Signal Connections and Signal Common 7 Signal circuits may have common electrical connections. One of these, which may or ma\ not be connected to earth, may be defined as the signal common.

2.10 Signal Isolation - The absence of an electrical connection between the signal loop and all other circuits and earth.

3. SPECIFIED VALUES

3.1 Ranges of Analogue dc Voltage Signals - The ranges ofanalogue dc voltage signals shall be as given in Table 1.

3.2 Ripple Content - The following values, applicable when using the ripple free dc power supply, should be specified:

. . a) The ripple content within a system element and its frequencies,

and

b) The noise generated internally within a system element and its frequencies.

3.3 Signal Common - For unipolar signals, signal negative should be signal common. If the signal common is connected to a dc power supply, it Should be connected to the power Supply negative.

IS : 8493 - 1977

TABLE 1 RANGES OF ANALOGUE dc VOLTAGE SIGNALS

( c1uusc 3.1 )

LOWER LIMIT UPPER LIMIT

V V

+1 + 5*

0 + 4* 0 + 5*

0 +10*

-10 +1ot

*Voltage ‘signals which can be derived from the dc current signals specified in IS : 7728-1975 Analogue dc current signals for process control systems.

TVoltage signal which can represent physical quantities with inherent bipolar nature.

3.3.1 For bipolar signals, the signal neutral should be the signal common. If the signal common is connected to a dc power supply, it should be connected to the power supply neutral.

3.4 Earthing - For unipolar signals, if the element is to be earthed, the signal negative and/or the de power supply negative, should be specified.

3.4.1 For bipolar signals, if the element is to be earthed, the signal neutral and/or the dc power supply neutral should be earthed.

5

INDIAN STANDARDS

ON

ELECTRICAL INSTRUMENTS FOR INDUSTRIAL PROCESSES

IS:

2053-1974

2054-1962

2055- 1962

2056-1962

2057-1962

271 I-19GF

2806- 1964

2848-1965

4309-1967

5883-1970

6720-1972

6804-1972

7358-1974 7122-1975

7728-1975 7988-1976

8018-1976

8493-1977

8495 ( Part

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