Module Title: Scada and Industrial Networks

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1 CORK INSTITUTE OF TECHNOLOGY INSTITIÚID TEICNEOLAÍOCHTA CHORCAÍ Semester 2 Examinations 2008/09 Module Title: Scada and Industrial Networks Module Code: ELEC 8014 School: Electrical & Electronic Engineering Programme Title: Bachelor of Science (Honours) in Electrical Power Systems Programme Code: EELPS_8_Y4 External Examiner(s): Internal Examiner(s): Mr. Gerard Beecher and Dr. Maeve Duffy Mr. Richard Daly Instructions: Answer THREE questions Duration: 2 Hours Sitting: Summer 2009 Requirements for this examination: Note to Candidates: Please check the Programme Title and the Module Title to ensure that you have received the correct examination paper. If in doubt please contact an Invigilator. Page 1 of 8

2 Q1 (a) A motor is to be controlled from two stations. One of these is local to the machinery being controlled and the other is in a remote SCADA control room. The local control station has a three-position selector switch (Manual/Off/Auto) and push buttons for Start-Forward, Start-Reverse and Stop. The local operator has control when the selector is set to Manual. Control of the motor is handed over to the SCADA operator when the local operator selects Auto. This setting will set a message for the SCADA operator. List the declarations for all Inputs/Outputs, to be used in the FB program instructions for the starter. 8 marks (b) Write a program in Ladder instructions for the control of the motor, such that the SCADA operator has no control when Manual is selected at the local station. The local operator however must still be able to stop the motor when Auto is selected. The program must also include the networks and instructions necessary to create numerical values that will be used in the SCADA picture program to create the following motor status messages on the operator s starter panel shown in Fig. 1 of Q2: Message 0 = Selector Switch Set To Off Message 1 = Manual Control Selected Message 2 = Ready For Control Room Message 3 = Motor Running Forward Message 4 = Motor Running Reverse Message 5 = Motor Tripped 20 marks (c) Draw the block diagram of the FB called from OB1 showing the Input and Output declarations created in the FB program. 5 marks Q2. (a) Describe the procedure for creating and launching the WinCC OS (Operator Station) software in Siemens Step7 Simatic Manager Software Package. 6 marks (b) (c) Explain how external tags are created in WinCC to enable the SCADA motor controller to start and stop the motor and to receive the necessary status messages created by the program in Q1. Explain the tag properties that can be selected in the tag dialog box and how they are linked to the controlling PLC master. Show the listing of the tag names created for the starter panel, their type, and address. 10 marks Fig. 1 on Page 3 shows the starter controls used by the operator in the WinCC station. List the steps used in the Graphics Editor to carry out the following. (i) Enable the mouse to trigger the actions required by each button. (Hint: Properties, Event tab, Mouse, Direct Connection) 8 marks (ii) Enable the motor status texts, outlined in Q1, to be displayed in the static text window. (Hint: Properties, Output/Input, Data Format, Output Value). 9 marks Page 2 of 8

Fig. 1 Q3 (a) List the essential components of an AS-in system, explain how the slaves are powered and how data is transmitted on the network. 6 marks (b) (c) (d) (e) AS-i Ver. 2.

3 Fig. 1 Q3 (a) List the essential components of an AS-in system, explain how the slaves are powered and how data is transmitted on the network. 6 marks (b) (c) (d) (e) AS-i Ver. 2.0 allows for 31 slaves to be addressed by means of 5 address bits. Given that each slave can have a maximum of 4-inputs and 4-outputs, determine the maximum possible number of inputs and outputs that can be addressed on one network and explain how this maximum can be achieved in practice. 3 marks AS-i Ver. 2.1 allows for 62 slaves using the same 5 address bits. How is this achieved? Determine the maximum possible number of inputs and outputs using this version and explain your assessment. What is the maximum number of inputs and outputs possible in one slave? Explain your answers. 4 marks Describe by means of a fully labelled diagram how the length an AS-i network can be extended from its unmodified maximum of 100m to 400m. 6 marks The following is a list of slave types, connected to an AS-i network. Slave No. Inputs/Outputs Slave No. Inputs/Outputs 0 1 OUT OUT OUT OUT 2 OUT OUT OUT IO 3 OUT OUT IN IN 4 IO IO IO IO 5 OUT OUT IO IO 6 IN OUT OUT OUT 7 IN IO IO IO 8 OUT IO IO IO 9 OUT IN IN IN Construct a PLC memory image table with appropriate headings for the fitted slaves. The start byte address for inputs is IB16 and for outputs QB Marks (f) List three advantages of using an AS-i network vis-à-vis the conventional centralised I/O system. 4 marks Page 3 of 8

4 Q4 (a) Explain, by means of basic sequential function chart diagram examples with at least six steps in each case, the implementation of: (i) Alternative branch; 6 marks (ii) Simultaneous branch. 6 marks (b) The process shown in Fig. 2 involves the mixing and cooking of three ingredients. Tanks 1, 2, and 3 are ingredient measuring tanks which must all be full before the process begins. The ingredients are to be emptied in turn into the mixing vessel in the order 1, 2, and 3 where they will be heated and agitated. The contents must be agitated for a minimum of ten minutes but must continue for as long as it takes the product to reach the required temperature. The cooked contents must then be discharged until the mixing vessel is empty. The sequence can be repeated for a batch of 10 before being reset for the next batch. The three status lamps must operate as follow: Waiting lamp: On when process is ready to start, i.e. all ingredients are available and cooking vessel is empty. Progress lamp: On from beginning to completion of process. Maintenance lamp: On when batch count is complete. (Reset when maintenance is complete and system is ready) Devise a solution based on a sequential function chart program, showing clearly the type of action required at each step and also the conditions for step transitions. 18 marks Use the attached Action instructions and the empty program template to complete the SFC program for the process. (c) Show how the SFC FB is called from OB1. Use the minimum control block for the call and apply an input to the block to initialise the process. Explain the effect of this input on the sequence when its condition is TRUE. 3 marks Page 4 of 8

5 Fig. 2 Food Blending Plant Page 5 of 8

6 Graph7 -Standard Actions - with and without interlocks- Page 6 of 8

7 Event Dependant Actions - with and without interlocks Page 7 of 8

8 Counter Actions Timer Actions Page 8 of 8

Sample project Filling Station SIMATIC. STEP 7 Professional / WinCC Advanced V11 for Sample project Filling Station. Overview of the Getting.

Sample project Filling Station SIMATIC. STEP 7 Professional / WinCC Advanced V11 for Sample project Filling Station. Overview of the Getting. Overview of the Getting Started 1 Create "Filling Station" example project 2 SIMATIC STEP 7 Professional / WinCC Advanced V11 for Getting Started Inserting and configuring hardware 3 Programming the PLC