Page 3 - Contents; Revision
71 Contents A Few Words of Revision Here are the BitsCurrent Flow in the Ladder Diagram The PLC Cycle5 Introduction Normally-Closed (NC) Contact Solution Description and Test A Different Take on Latching... Introduction Solution OverviewEdge DetectionBit MemoriesSolution Description and Test Introdu...
Page 4 - Preface; Enjoy reading your primer!
1 Preface Dear S7-200 user, Efficiency in the use of micro controllers depends primarily on how quickly and safely you can learn to use a controller. We created the 1-and 2-hour primers so that even beginners can learn to handle the S7-200 quickly and easily. Building on the 1-hour primer, this 2-ho...
Page 6 - Chapter; Chapter header; Primer symbols; Menu
3 Chapter Text on a gray background prompts you to some action such as an input. This symbol shows you that the left mouse key must be clicked once for an action (e.g. mark field). This symbol shows you that the left mouse key must be double-clicked for an action. Here you are prompted to press the ...
Page 8 - - A Few Words of Revision
5 In addition, you were already able to pro-gram small logic operations yourself. You even learned to recognize timers in that short time. Compare with Page 24 in the 1-hour primer Revision What you know already... - A Few Words of Revision - Here are the Bits- Current Flow in the Ladder Diagram- Th...
Page 9 - Here are the Bits; This is represented as follows in LAD:
6 Here are the Bits The smallest unit to be processed is the bit!The bit can assume two states: 1) "1" meaning "bit set" or state is "true", 2) "0" meaning "bit not set " or state is "untrue", In a method familiar to you, the two binary states "1&#...
Page 10 - - Current Flow in the Ladder Diagram
7 Current Flow in the Ladder Diagram (1) In this example, output Q0.3 is active or "1", if the contact at I0.1 is closed, i.e. "1" (24 V DC at input I0.1) AND simulta-neously, the timer bit T37 is active, i.e. "1". Input I0.1 is now "1", i.e. contact I0.1 is closed. T...
Page 15 - Notes
12 Revision Notes Latching Revision Pulse-Oper- ated Switch Off-Delay Timer Sequencer Appendix
Page 16 - Introduction
13 Introduction You are sure to be familiar with the stan-dard latching function and here you will learn how to program it. The example: Output Q0.30 is to be activated as soon as S1 at input I0.0 is operated. With latch-ing, Q0.0 is to remain active until S2 at input I0.1 is operated and thus inter...
Page 17 - To allow the latching function to be termi-
14 Normally-Closed (NC) Contact To allow the latching function to be termi- nated again, input I0.1 is to work like a break in the current path when operated. If a current path is interrupted (i.e. state "0" exists) when a switch is operated, this is referred to as an NC contact. Consequentl...
Page 18 - Always terminate text field inputs; by pressing Enter; Select the NC contact with the
15 Normally-Closed (NC) Contact (2) Latching Latching - Introduction - Normally-Closed (NC) Contact - Solution Description and Test- A Different Take on Latching An NC contact interrupts the "current flow" in the ladder diagram when the input or output assigned to it is "true". Inser...
Page 19 - Solution Description and Test; - Solution Description and Test
16 Solution Description and Test As in the contactor circuit, you have also switched a contact of the output (Q0.0) parallel to the tripping element (I0.0). If, during a cycle, output Q0.0 has been activated by operation of switch S1 at I0.0, contact Q0.0 parallel to I0.0 appears closed in the very ...
Page 20 - - A Different Take on Latching
17 A Different Take on Latching ... (1) In PLC technology, latching is often also implemented in another variant: Instead of feeding back the output - as in the previous example - here the functions "Set" and "Reset" are simply used instead. Have a look first at the ladder diagram be...
Page 21 - You have already learned how to enter; the list of operations that then opens.; In the already activated text field,
18 A Different Take on Latching ... (2) You have already learned how to enter I0.0 and I0.1. Enter the set and reset coil as follows: Latching Latching - Introduction- Normally-Closed Contact- Solution Description and Test - A Different Take on Latching 8 Mark Ë -(S)- ? Address © Enter Set (S) or re...
Page 22 - Safety notes; • In the above example, an NC switch S3 was used for resetting.
19 Safety Aspects Shutdown if Wirebreak at Connection to S3 Switch with NC contact that supplies the signal "0" when operated. In LAD, this signal is reversed by the NC contact I0.1 This means that if you oper-ate the switch S3, Q0.0 is reset. Safety notes • In the above example, an NC switc...
Page 24 - Principle of operation; Pulse-Operated Switch
21 Introduction You will implement a pulse-operated switch here. Within this context, you will learn about edge detection and bit memories. Principle of operation A lamp at output Q0.5 is to be switched on as soon as S1 at input I0.0 is briefly operated. If S1 (I0.0) is operated again, Q0.5 drop out...
Page 25 - Solution Overview
22 Solution Overview Before showing you the step-by-step solution of the task, we will show you the finished solution in order to provide you with an overview. Pulse-Operated Switch - Introduction - Solution Overview - Edge Detection- Bit Memories- Solution Description and Test "Reversing" t...
Page 26 - In our example, we use the function as follows:
23 Edge Detection (1) The moment of transition of a contact (input, output ...)from "open" to "closed" or from "untrue" to "true" is referred to as the rising or positive edge. Correspondingly, the transition from "closed" to "open" or from "true&#...
Page 27 - Pulse-operated switch; Use the mouse to mark the position; to be replaced by an edge detection.; Select ”Contacts” with a single
24 Edge Detection (2) In our "Two-way Switch",is therefore used to pass on a signal to the subsequent logic operations only at the moment that the button at I0.0 is pressed. Correspondingly, the contact for detecting falling edges is closed for the duration of one cycle in the event of chang...
Page 30 - and
27 Solution Descriptionand Test To summarize, the function of our now complete program is explained again below using the example of the upper branch of Network 1 (ends with (S), switch on): The "current flow" in the ladder diagram is represented at I0.0 in the positive edge cycle! If I0.0 i...
Page 32 - Timing chart
29 Introduction If S1 is switchedoff, the fan is to continue to run for 3 seconds Off-delay timer - Introduction - Save As ...- Insert Network- Solution Description- Enter Comments You are already familiar with the On-delay timer from the 1-Hour Primer. We will now implement an Off-delay timer toget...
Page 33 - Procedure; ) First, load the complete latching circuit from our first
30 Introduction Procedure 1) First, load the complete latching circuit from our first example from the hard disk. 2) Then, save the example under a new name on the hard disk. 3) Then we create space with "Insert Network" 4) We then work together to complete the off-delay timer with comments....
Page 34 - disk. You stored it there in the first chapter.; Call the menu function
31 Save As ... Off-delay timer - Introduction - Save As ... - Insert Network- Solution Description- Enter Comments We will use the latching circuit from the first chapteras the basis for our project. Duplicate the entire project by loading it and thenimmediately saving it under another name. Í Menu:...
Page 35 - Insert Network; Activate the title field of Network 2 by; simply clicking the mouse.; Insert a new network in place of
32 Insert Network An additional network is to be inserted in place of Network 2 so that we can imple-ment the off-delay timer. The following steps are required for this purpose: Off-delay timer - Introduction- Save As ... - Insert Network - Solution Description- Enter Comments 8 mark Ë Network butto...
Page 36 - - Solution Description
33 Solution Overview Off-delay timer - Introduction- Save As ...- Insert Network - Solution Description - Enter Comments I0.0 activates Q0.0Q0.0 maintains its state (latches) since it is also switched simulta-neously in parallel with I0.0. This is how the finishedprogram appears.. Off-Delay Timer Wh...
Page 37 - Solution - Enter Program; Network 1 must look like this:
34 Solution - Enter Program Network 1 must look like this: Enter the following program in Network 2: Off-delay timer - Introduction- Save As ...- Insert Network - Solution Description - Enter Comments Overwrite I0.1 of the latching circuit with T37. Enter T37 with F2 Timers/Counters and F3 Timer as ...
Page 38 - Solution Description
35 Solution Description This is how ourprogram functions. Ithas two active phases. Phase 1: Activation of the latching circuit, I0.0 is "1" (we assume that Q0.0 is not active). If I0.0 is operatedANDT37 has not elapsedTHENQ0.0 is activated (="1"). Q0.0 latches via this contact. T37 d...
Page 39 - The Comment Editor is now
36 Enter Comments (1) Off-delay timer - Introduction- Save As ...- Insert Network- Solution Description - Enter Comments 8 2x ? Title ? Comments 8 OK Well done! Maybe it has already occurred to you that it would be helpful for later work (modifications and such like) to store notes in the program on...
Page 41 - Diploma
38 Time To Show What You Know Please read and answer the questions below. ✔ How do you implement an off-delay timer? Draw the ladder diagram for two possible solutions. Once with the normal coil —( )— and once with (S) and (R). ✔ How do you save a project? ✔ How do you determine the value of a timer...
Page 42 - Sequencer; Sequential control
39 Introduction Sequencer Sequential control - Introduction - Basics- Working with Sequencers- Modification- Solution Description, Example- Test Now we will implement a sequencer together. A drill motor is started clockwise with S1. After 3s, the feed is activated. When the depth limit at I0.3 is re...
Page 43 - Solution Starting Point
40 Solution Starting Point First cycle SM0.1 Motor protection I0.5 Stop I0.0 Sequencer Sequential control - Introduction - Basics- Working with Sequencers- Modification- Solution Description, Example- Test This is what the solution for the sequencer of the drill example looks like. Start S1 Depth li...
Page 44 - What is a sequencer control?; Step flag; Motor on
41 Basics (1) What is a sequencer control? • A control method in which a task is broken down into verysmall, usually sequential, subtasks (e.g. Motor on, feed on, feed off, ...). • The subtasks (functions) are called steps. • Usually one step has to be completed before the next one is started. • A n...
Page 45 - What is a transition condition?
42 Basics (2) What is a transition condition? • Each step is started (activated) by a condition). The condition is usually derived from the states of themachine. These can include actuated limit switches,operator keys, temperatures reached or timers. • An active preceding step is almost always part ...
Page 46 - The two program sections of a sequencer control:; ) The conditions for
43 Basics (3) The two program sections of a sequencer control: Sequencer Sequential control - Introduction - Basics - Working with Sequencers- Modification- Solution Description, Example- Test 1) The conditions for activating the individualsteps (subtasks) are logically combined withthe individual s...
Page 48 - If the task is more complex, it is best to use a further sequencer.; Sequencers; - Working with Sequencers
45 Working with Sequencers (1) • A separate memory bit (step flag) is assigned to each step. This is "1" if the step is active. • For the sake of clarity, only one step in a sequencer should beactive at any time. This means only one step flag should be "1". • If the task is more comp...
Page 50 - condition is missing.; Machine; - Using sequencers forces you to structure your programs
47 Working with Sequencers (3) Advantages • The control section of the sequencer and the setting of the outputs are kept separate - If an output is now to be active in step 7 in addition to step 2 and 3, the program need only be modified at one point. - Modifications to the control section of the se...
Page 53 - Modification; This is controlled by:
50 Modification Sequencer Sequential control - Introduction- Basics- Working with Sequencers - Modification - Solution Description, Example- Test Network 6 determines in which step the program jumps to step 5. In the example, it jumps in step 0. This is controlled by: Setting M0.0 and resettingM0.1 ...
Page 56 - Step flag M0.0 is set
53 Solution Description, Example (3) Activating timer T37 If step 1 is active (M0.1 = "1"), timer T37 is started. Activating timer T38 If step 4 is active (M0.4 = "1"), timer T38 is started. Initialization of a sequencer Step flag M0.0 is set 1) in the first cycle (SM0.1 is "1...
Page 57 - Program section 2 - Setting the outputs
54 Solution Description, Example (4) Program section 2 - Setting the outputs Activate output Q0.0 (drive clockwise) Output Q0.0 is "1" in steps 1, 2, 3, 4, i.e. if M0.1 or M0.2 or M0.3 or M0.4 are "1". Activate output Q0.1(direction reversal) Output Q0.1 is "1" in steps 3 and...
Page 58 - Test
55 Test You can enter the program yourself or load the file "d05.prj" from the diskette. Please note that the stop switch I0.0 and the motor protection I0.5 are "normally-closed (NC) contacts". This has been implemented in this way for safety reasons. A wirebreak between the switches...
Page 66 - Bridge Circuit; ) Simple bridge circuit; Appendix; Tips
63 Bridge Circuit If you are changing over from contactor technology to PLC technology will very probably encounter switch combinations that cannot be converted directly into ladder diagram representation. Included among these is the bridge circuit. Brief solutions are sketched here both for the sim...
Page 67 - Diode Circuit
64 Diode Circuit When diodes have been used in "old" circuit diagrams converting them into ladder diagram terms is not an altogether simple matter. Since diodes represent connection lines in principle but only conduct current in one direction, a similar solution is adopted here as with the b...
Page 68 - Changeover Switch; The current path is graphically highlighted.
65 Changeover Switch Changeover switches should likewise not cause you any problem when you are converting a circuit diagram into a ladder diagram. This transformation is explained briefly below. The current path is graphically highlighted. Changeover switch b is then divided into a normally closed ...
Page 70 - Index; Coil: Representation for an output element in
67 Index A...I This index contains the most impor tant terms in programming the S7-200. You will find brief explanations of the abbreviations used in the Primer as well as some cross refer-ences to the One Hour Primer. The following symbol is used in the Index: 1h- & References to pages in the 1...
Page 71 - Sequential control: Control that derives steps
68 Index K...S Index For reference, cross references to manuals and abbreviations. $ K L Ladder diagram: 1h- & 25 Ladder status: 7, 1h- & 26 Latching function solution: 15 +Latching: 13 + M MB: Memory byte (8 bits)MD: Memory double-word (32 bits)Mode selector switch: Switch on the S7-200 wit...
Page 73 - Thank you; Position
70 ToSiemens AG Fax: +49 911 895-2786 A&D AS MVMGleiwitzer Str. 555 90475 NuernbergGermany Response to the "Two-Hour Primer" Dear user of the Micro PLC S7-200, We created the Two-Hour Primer so that, building on the One-Hour Primer, you can learn touse the Micro PLC S7-200 within a very ...
