Micro SystemSIMATIC S7-200sTwo Hour Primer Edition 01/2000
7Current 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" (
8Current Flow in the Ladder Diagram (2) (Using the Help Function)Help displays1 Markelement2. F1 F1 On-line-helpRevisionWhat you know already...- A F
9The PLC Cycle (1)All SIMATIC programmable controllers usually work in a cyclical manner. In this cyclical operation the switch statuses are read at t
10The PLC Cycle (2)The outputs in the process-image output table (PIQ) are overwritten in accordance with the switching logic in the program. The stat
11The PLC Cycle (3)RevisionWhat you know already...- A Few Words of Revision- Here are the Bits- Current Flow in the Ladder Diagram- The PLC Cycle
12RevisionNotesLatching RevisionPulse-Oper-ated SwitchOff-Delay TimerSequencer Appendix
13IntroductionYou 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 t
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
15Normally-Closed (NC) Contact (2)LatchingLatching- Introduction- Normally-Closed (NC) Contact- Solution Description and Test- A Different Take on
16Solution Description and TestAs in the contactor circuit, you have also switched a contact of the output (Q0.0) parallel to the tripping element (I0
Safety GuidelinesThe Two Hour Primer was created as a quick introduction to the world of S7-200 andhas deliberately been kept short. It is not a subst
17A Different Take on Latching ... (1)In PLC technology, latching is often also implemented in another variant: Instead of feeding back the output - a
18A 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:LatchingLatching-
19Safety Aspects Shutdown if Wirebreak at Connection to S3Switch with NC contact that supplies the signal "0" when operated. In LAD, this si
20LatchingNotesLatching RevisionPulse-Oper-ated SwitchOff-Delay Timer Sequencer Appendix
21IntroductionYou will implement a pulse-operated switch here. Within this context, you will learn about edge detection and bit memories.Principle of
22Solution OverviewBefore showing you the step-by-step solution of the task, we will show you the finished solution in order to provide you with an ov
23Edge Detection (1)The moment of transition of a contact (input, output ...)from "open" to "closed" or from "untrue" to
24Edge 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
25Bit Memories (1)You require bit memories for the pulse-operated switch.A brief example will serve here to show you how to work with them.Instead of
26Bit Memories (2)Now that you know the function of bit memories, you will be able to understand the solution of the pulse-operated switch.At this poi
71ContentsA Few Words of Revision Here are the BitsCurrent Flow in the Ladder Diagram The PLC Cycle5IntroductionNormally-Closed (NC) ContactSolution D
27Solution Descriptionand TestTo summarize, the function of our now complete program is explained again below using the example of the upper branch of
28Time to ShowWhat You Know... because you’ve made some real progress! ✔ Read and answer the questions below.✔ What is the cycle of a PLC?what are the
29IntroductionIf S1 is switchedoff, the fan is to continue to run for 3 seconds Off-delay timer- Introduction- Save As ...- Insert Network- Soluti
30Introduction Procedure1) First, load the complete latching circuit from our first example from the hard disk.2) Then, save the example under a n
31Save As ...Off-delay timer- Introduction- Save As ...- Insert Network- Solution Description- Enter CommentsWe will use the latching circuit fro
32Insert NetworkAn 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 r
33Solution OverviewOff-delay timer- Introduction- Save As ...- Insert Network- Solution Description- Enter CommentsI0.0 activates Q0.0Q0.0 mainta
34Solution - Enter ProgramNetwork 1 must look like this:Enter the following program in Network 2:Off-delay timer- Introduction- Save As ...- Insert
35Solution DescriptionThis is how ourprogram functions. Ithas two active phases.Phase 1: Activation of the latching circuit, I0.0 is "1" (we
36Enter Comments (1)Off-delay timer- Introduction- Save As ...- Insert Network- Solution Description- Enter Comments82x?Title?Comments8OKWell don
1PrefaceDear 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
37Enter Comments (2)After adding the comments, onlythe network title is visible onscreen.The comments can be madevisible again later by re-activating
38Time To Show What You KnowPlease read and answer the questions below.✔ How do you implement an off-delay timer? Draw the ladder diagram for two
39IntroductionSequencerSequential control- Introduction- Basics- Working with Sequencers- Modification- Solution Description, Example- TestNow w
40Solution Starting PointFirst cycle SM0.1Motor protection I0.5Stop I0.0SequencerSequential control- Introduction- Basics- Working with Sequencers-
41Basics (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,
42Basics (2)What is a transition condition?• Each step is started (activated) by a condition). The condition is usually derived from the states of the
43Basics (3)The two program sections of a sequencer control:SequencerSequential control- Introduction- Basics- Working with Sequencers- Modificati
44Basics (4)1) Controlling the sequencer/making transitions in the sequencer2) Setting the outputs via the step flagsSequencerSequential control- Int
45Working 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
46Working with Sequencers (2)The transition condition is in practice also made up of several contacts.Our example can be expanded in such a way that,
2 Latching RevisionPulse-Oper-ated SwitchOff-Delay TimerSequencer Appendix
47Working 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
48Important Safety Points (1)The program section shown in the example must be at the end of the "normal" tran-sition conditions of the seque
49Important Safety Points (2)Program section 1 – Making transitions in the sequencer:Before assigning the first output d, the program section for acti
50ModificationSequencerSequential control- Introduction- Basics- Working with Sequencers- Modification- Solution Description, Example- TestNetwo
51Solution Description, Example (1)Program section 1 - Making transitions in the sequencerActivating step 1Step flag M0.1 is set when the sequencer is
52Solution Description, Example (2)Activating step 4Step flag M0.4 is set if the sequencer is at step 3 (M0.3 ="1") AND input I0.4 (initial
53Solution Description, Example (3)Activating timer T37If step 1 is active (M0.1 = "1"), timer T37 is started.Activating timer T38If step 4
54Solution Description, Example (4)Program section 2 - Setting the outputsActivate output Q0.0 (drive clockwise)Output Q0.0 is "1" in steps
55TestYou 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 p
56SequencerNotesLatchingRevisionPulse-Oper-ated SwitchOff-Delay TimerSequencer Appendix
3ChapterText 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 a
57Made it.Now you can solve tasks yourself using the S7-200. If you want to implement complex contactor circuits, you can find some useful tips in the
58 Latching RevisionPulse-Oper-ated SwitchOff-Delay Timer Sequencer Appendix
59Fancy Some More?You can find more examples in the "Samples" folder in your STEP 7-Micro/WIN folder or the "Tips & Tricks" fo
60 Latching RevisionPulse-Oper-ated SwitchOff-Delay Timer Sequencer Appendix
61We have put together a few examples below to make it easy for you to imple-ment even complex "switching opera-tions" in ladder logic.Latch
62 Latching RevisionPulse-Oper-ated SwitchOff-Delay Timer Sequencer Appendix
63Bridge CircuitIf you are changing over from contactor technology to PLC technology will very probably encounter switch combinations that cannot be c
64Diode CircuitWhen diodes have been used in "old" circuit diagrams converting them into ladder diagram terms is not an altogether simple ma
65Changeover SwitchChangeover switches should likewise not cause you any problem when you are converting a circuit diagram into a ladder diagram. This
66NotesAppendixTipsNotes. A4Latching RevisionPulse-Oper-ated SwitchOff-Delay TimerSequencer Appendix
4 Latching RevisionPulse-Oper-ated SwitchOff-Delay Timer Sequencer Appendix
67Index A...IThis index contains the most important terms in programming the S7-200. You will find brief explanations of the abbreviations used in
68Index K...SIndexFor reference, cross references to manuals and abbreviations.$KLLadder diagram: 1h-& 25Ladder status: 7, 1h-& 26Latching
69Index T...ZIndexFor reference, cross references to manuals and abbreviations.$TT37 (Timer): 29 +TERM: Position of the S7-200’s mode selector switch
70ToSiemens AG Fax: +49 911 895-2786A&D AS MVMGleiwitzer Str. 55590475 NuernbergGermanyResponse to the "Two-Hour Primer"Dear user of the
72AppendixTipsNotes.
5In addition, you were already able to pro-gram small logic operations yourself. You even learned to recognize timers in that short time.Compare with
6Here are the BitsThe smallest unit to be processed is the bit!The bit can assume two states:1) "1" meaning "bit set" or state is
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