3511/ 1 TSO NTERNATIONAL STANDARD INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.MI 'K.IY HAPO.IHA OPI AH3AM IO CTAHIAPTM3ALIMW.ORGANISATION INTERNATIONALE DE NORMALISATION Process measurement control functions and instrumentation Symbolic representation Part I : Basic requirements Fonctions et instrumentation pour la mesure et la regulation des processus industriels -- Representation symbolique Partie / : Principes de base First edition -- 1977-07-15 ISO 3511/1-1977 (E) UDC 621-5 : 003.62/.63 : 744.4 Ref. No. ISO 3511/l-1977 (E) controlfunctions,engineeringdrawings,graphicsymbols Price based on 10pagtes ed without license from IHS Not for Resal FOREWORD Iso (the International Organization for Standardization) is a worldwide federation of national standards institutes (ISO member bodies). The work of developing International Standards is carried out through ISO technical committees. Every member body interested in a subject for which a technical committee has been set up has the right to be represented on that committee. International organizations, governmental and non-governmentai, in liaison with tsO, aiso take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISo Council. International Standard ISO 3511/l was developed by Technical Committee ISO/TC 10, Technical drawings, and was circulated to the member bodies in October 1974. It has been approved by the member bodies of the following countries : Australia Hungary Romania Austria India South Africa, Rep. of Belgium Ireland Spain Bulgaria Mexico Sweden Chile Netherlands Switzerland Denmark New Zealand Turkey France Norway United Kingdom Germany Poland Yugoslavia The member bodies of the following disapproval of the countries expressed document on technical grounds : Canada Finland Italy U.S.A. International Organizstion for Standardization, 1977 Printed in Switzerland Copyright International Organization for Standardization ed without license from IHS Not for Resale ISO 3511/1-1977 (E) INTERNATIONAL STANDARD Process measurement control functions and instrumentation -- Symbolic representation - Part I : Basic reguirements 0 INTRODUCTION 2 DEFINITIONS This International Standard has been devised to provide a The following definitions are used solely for the purpose of universal means of communication between the various this International Standard to assist in the application and interests involved in the design, manufacture, installation understanding of the symbol system and operation of measurement and control equipment used 2.1 point of measurement : The point in a process at in the process industries. which a measurement is or may be made. Requirements within the industries vary considerably, and in recognition of this, this International Standard is 2.2 instrument : A device or combination of devices used presented in three parts as follows : directly or indirectly to measure, display and/or control a Part I : Basic requirements (directed towards the needs variable. This term does not apply to internal components of those whose prime interest is in basic measurement of the instruments, for example resistor or receiver bellows. and control means). 2.3 panel-mounted instrument : An instrument that is Part Il : Extension of basic requirements. mounted in a group normally accessible to the operator Part Ill : Detailed symbols. The three parts together are intended 2.4 locally mounted instrument : An instrument that is not panel mounted. a) to meet the requirements of those who, possibly employing more sophisticated measurement and contro! means, may wish to depict such aspects as the 2.5 correcting unit : The unit comprising those elements measurement techniques embodied in a particutar ins- (actuating and which adjust the correcting correcting) trument, or the means -- hydraulic, pneumatic, electrical, conditions, in response to a