DURBAN UNIVERSITY OF TECHNOLOGY DEPARTMENT OF ELECTRONIC ENGINEERING STUDY GUIDE TO PROCESS INSTRUMENTATION 2

Transcription

1 DURBAN UNIVERSITY OF TECHNOLOGY DEPARTMENT OF ELECTRONIC ENGINEERING STUDY GUIDE TO PROCESS INSTRUMENTATION Latest Revision: July 06

2 SUBJECT: PROCESS INSTRUMENTATION SAPSE CODE: PRSI0 PRE-REQUISITES: ELECTRONICS ELECTRICAL ENGINEERING CAMPUS: STEVE BIKO CAMPUS. METHOD OF ASSESSMENT: Progress will be monitored by means of two class tests each of one hour duration. The two class tests will make up the course mark for which a sub-minimum of 40% will be required for permission to write the final examination. The practical component of the course will be incorporated in the three theory tests. The final mark will then be made up as follows: Course mark Theory Test 50 % Theory and Practical Test 50 % Total 40 % Examination mark 60 % Final mark 00 %. COURSE PURPOSE: The course is intended to introduce the student to basic automatic control systems and cover instrumentation fundamentals not covered in Process Instrumentation which is run concurrently. The course is descriptive in nature and some sections are coupled with calculations. Where possible practical work is used to backup the theory. Students are expected to make use of the extensive library facilities as many books in the field of instrumentation and control are available. 3. LECTURER: The lecturer for this course is Mr. Sugith Sewdass. Office S8 level 4, Phone (03) COURSE DURATION: The course extends over one semester of study and is presented as three theory lectures per week and two practical periods per week. Additional tutorial sessions may be included. 5. PRACTICAL ATTENDANCE:

3 90% practical attendance is compulsory and practical s are treated the same as a test or exam.a learner who for any reason is absent from a particular laboratory period, must provide acceptable proof of his/her reason for absence to the lecturer concerned within two () days of his/her return to classes. Failure to provide proof of acceptable reasons for absence shall result in a zero mark for the practical component of the course mark as per rule BT5 (Departmental Rules: General handbook.) 5. Lab Rules. No eating or drinking in the laboratories (including the chewing of gum).. Closed shoes are to worn at all times (slip-slops, bare feet and open shoes are not allowed). 3. No cell phones may be used while in the laboratories. 4. No unsupervised access is allowed in any of the laboratories. Permission must be given before entering a laboratory. 5. Students are required to bring their own tool kits including breadboards to their practical sessions. 6. TEST DATES: Test Date: TBA Venue: TBA Time: TBA Test Date: TBA Venue: TBA Time: TBA 7. BOOKS: The prescribed book for this course is: van Vuuren, G, An to Process Instrumentation, 3 rd Edition. Quad Technologies, Durban, 00. Students should also make use of the extensive range of instrumentation books in the Campus library. Several reference books will be found to be most useful, especially:. Liptak, B G, Instrument Engineers Handbook. Considine, D M, Process Instruments and Controls Handbook 8. DATA SHEET: A data sheet is provided for use in all class tests and the main examination. This data sheet gives basic physical data as well as a list of the important equations that are used during the Process Instrumentation course. A copy of the data sheet can be found attached to this document. 3

4 9. SUBJECT SYLLABUS: 9. Process Control Basics terms and definitions Process and instrument diagrams (P&ID) On / off control Continuous control PID 9. Transmission Signals / Telemetry Analogue signals Pressure, voltage, current, frequency + standards Loop powered instruments Signal conversion + calculations Digital signals / networks RS3, RS485, TCP/IP HART protocol 9.3 Flow Bernoulli s derivation, correction coefficients, calculations DP flow measurement Venturi tube, Dall tube, orifice plate, target meter Open channel flowmeters weirs and flumes Variable area flowmeter Turbine flowmeter Ultrasonic flowmeters + calculations Electromagnetic + calculations Vortex shedding Mass flowmeters Thermal Coriolis Positive displacement flowmeters 9.4 Valves & Actuators Valve flow characteristics Valve types Cavitation Valve flow coefficient Actuators Positioners 9.5 Pumps 0. OUTCOMES: Types of pumps Control methods Coupling VSD s for pump control 4

5 At the end of this course the learner will know how to measure the following basic variables: viscosity specific gravity, density, volumetric flow and mass flow. The learner will also have a good knowledge of both on/off and basic PID control systems, the control of flow using automatic control valves, pumps as well as both analogue and digital signal transmission. The learner will also be able to read and understand P&ID and loop diagrams. Basic electronic skills will be developed and demonstrated. Outcomes Assessment Method Syllabus The learner will know the difference between on/off control and continuous control, and will know what the function is of the proportional, integral and derivative stage of a controller in a feedback control system. questions based on the operation of the various types of process control methods. See section 9.. The learner will know how to measure flow in both open channels and closed conduits. The measurement of volumetric flow and mass flow will be known. The learner will know how to control flow rate in a system, the various types of valves available and problems associated with incorrectly sized valves on a process. The learner will also know basic calculations based on valve flow coefficients. The learner will know the various types of pumps available as well as the methods of controlling these pumps. The learner will know the difference between analogue and digital signals and the standards available. The learner will also know methods of converting between the various types of analogue signals. questions based on operation of various flow measurement devices and be able to perform calculations relating to flow measurement. questions relating to the control of flow as well as the problem of cavitation. The learner will also be required to perform calculations based on valve flow coefficients. questions based on pumps and the control of pumping rate and volume. questions based on analogue and digital signals and to perform various calculations based on these signals. See section 9.3. See section 9.4. See section 9.5. See section 9.. 5

6 PROCESS INSTRUMENTATION DATA Conversion Table for Pressure Units Unit bar kpa psi mmhg kg/cm atm torr bar 00 4, ,064,097 0,9869 0,0033 kpa 0,0 0,4504 7, ,00 0, ,0088 psi 0, , ,75 0,0703 0, ,063 mmhg 0,0033 0,333 0,0934 0,0036 0,003 kg/cm 0, ,0665 4,33 735,56 0, ,559 atm,035 0,35 4, , ,784 torr 0,3333 0, , ,00036 Thermocouple Reference Table º C ,00 0,50,0,54,06,58 3, 3,56 4,9 4,73 Type J Type K 00 5,7 5,8 6,36 6,90 7,45 8,00 8,56 9, 9,67 0, 00 0,78,34,89,45 3,0 3,56 4, 4,67 5, 5, ,33 6,88 7,43 7,98 8,54 9,09 9,64 0,0 0,75,30 400,85,40,95 3,50 4,06 4,6 5,6 5,7 6,7 6, ,39 7,95 8,5 9,08 9,65 30, 30,80 3,37 3,95 3, , 33,70 34,9 34,88 35,48 36,08 36,69 37,30 37,9 38, ,5 39,78 40,4 4,05 4,68 4,3 4,96 43,60 44,5 44, ,53 46,8 46,8 47,46 48,09 48,73 49,36 49, º C ,00 0,40 0,80,0,6,0,43,85 3,6 3, ,0 4,5 4,9 5,33 5,73 6,3 6,53 6,93 7,33 7, ,3 8,54 8,94 9,34 9,75 0,6 0,57 0,98,39,80 300,,63 3,04 3,46 3,88 4,9 4,7 5,3 5,55 5, ,40 6,8 7,4 7,67 8,09 8,5 8,94 9,36 9,79 0, 500 0,65,07,50,9,35,78 3,0 3,63 4,06 4, ,9 5,34 5,76 6,9 6,6 7,03 7,45 7,87 8,9 8, ,4 9,56 9,97 30,39 30,8 3,3 3,65 3,06 3,48 3, ,30 33,7 34, 34,53 34,93 35,34 35,75 36,5 36,55 36, ,36 37,76 38,6 38,56 38,95 39,35 39,75 40,4 40,53 40, ,3 4,70 4,09 4,48 4,87 43,5 43,63 44,0 44,40 44,78 Constants 3 Hg 3600 kg / m 3 WATER 000 kg / m g 9,8m / s speed of sound dry air 344m / s speed of sound water 46m / s Temperature Conversions T t Kelvin t Celsius 5 t 9 C F 73,5 3 6

7 Formulae N N 0 e ln t P ABS P P Manometer t ATM P G gl a A Hg H h L Hg H h H L Hg Z h L R l A V R t OBridge R VSeG x 0 00 t R R 00. R B T R Ae 0 0 sin E Q A m v g P. Ae P e e. 5 L 0.H Q RECT H.5 Q TRAP 0.095LH.5 Q V 0.07 tan H.5 Q FLUME 4.43CBKH Ae Q BD AC FT FR Q cos FT AC Q T L cos Ad Q F St H W CPt C V N Q Q min Q P R x xmax VALVE Q CZEd h -7-