Manual de step 7

Ejemplo: Si se produce un flanco positivo cambio de 0 a 1 en E0. El funcionamiento es similar. La salida es 1 cuando finaliza el tiempo programado. El temporizador no vuelve a arrancar mientras el RLO no cambie de 1 a 0. Queremos controlar un acceso mediante una puerta corredera. El funcionamiento de la puerta es el siguiente: Queremos que cuando alguien pise en la goma del suelo, se abra la puerta Motor A4.

La puerta se a b r e hasta que llegue al final de carrera E0. Cuando llega al final de carrera, comienza a cerrarse Motor A 4.

Tenemos dos pulsadores de control. El de marcha M y el de paro P. Cuando le demos al pulsador de marcha queremos que el funcionamiento sea el que hemos explicado anteriormente. Cuando le demos al de paro queremos que deje de funcionar. Es decir, si alguien pisa la goma no queremos que se abra la puerta. Queremos hacer un contador que a partir de que le demos al pulsador de marcha, comience a contar una unidad cada segundo hasta llegar a Cuando llegue a 60 queremos que siga contando una unidad cada segundo pero en sentido descendente.

Queremos que haga la siguiente cuenta: 0, 1, 2, 3, 4, Cuando le demos al pulsador de paro queremos que deje de contar. Cuando le demos de nuevo al pulsador de marcha probaremos dos cosas: 1 Que siga contando por donde iba. De esta forma podremos directamente operar en nuestro programa con unidades tales como grados, metros, gramos, litros, etc.

El escalado unipolar solo se desarrolla en el rango de valores positivos 0 a o negativos 0 a - Los valores comprendidos entre y son utilizados por la CPU para conocer e indicar el posible rebose y desbordamiento que se pueda producir en los niveles de entrada. El resultado es almacenado en la palabra baja del ACCU 1. El resto es almacenado en la palabra alta del ACCU 1.

El resultado 32 bits se guarda en el ACCU 1. RND Redondeo a entero. RND- Redondeo al entero inferior. En este ejemplo, hemos introducido en la entrada PEW el valor entero correspondiente a un nivel de 5 voltios en el sensor. Dicho valor quedara escalado en la salida OUT entre los valores 0. Queremos que al accionar la entrada E El resultado se escribe en la salida OUT. Cuando activemos la entrada E Al activar E En un bloque de datos DB no se programa nada.

Se utilizan para almacenar valores iniciales y leer o escribir datos actuales de determinadas variables, que posteriormente pueden ser usadas por el programa de usuario. Para guardar un dato, tenemos que poner nombre a la variable, definir el formato en el que lo queremos, y el valor inicial.

El valor inicial siempre es el mismo, su propio nombre ya lo indica. Podemos abrir primero un DB y luego acceder directamente a la palabra de datos, o podemos decir cada vez a que DB y a que palabra de datos queremos acceder. Tenemos una cinta transportadora por donde se desplazan piezas. Tenemos unas luces indicadoras de pieza buena o mala. Se consideran piezas buenas aquellas que tengan un peso entre 4 y 5 Kg.

Estos bloques constituyen la interface entre el sistema operativo del PLC y el programa de usuario. Las FC no tienen bloques de datos DB asociados. Desde el OB1 indicaremos cuando tiene que acceder a uno y a otro.

Programa en FC1: Cuando pulsemos E Programa en FC2: Cuando pulsemos E Esta llamada puede ser de tipo incondicional o condicional. La siguiente figura muestra la diferencia. El resultado lo tendremos presente en MW Estos valores pueden ser ahora diferentes. La almohadilla no la escribimos nosotros. Click Yes to perform the operation.

There are two methods for uploading. The first is when you have the original project and you want to preserve the symbols and comments. The second method, when you don't have the original project, will upload everything from the CPU but will have no associated documentation i. This will open up another window called the Online Partner. It shows the existing blocks inside the CPU. The Online version is indicated by the highlighted title bar. There is a connection between these two versions so that uploading from the online partner makes sure to preserve all the symbols and comments.

Be careful. After uploading, make sure to close the online partner and do all work from the offline version. For a full upload, select the Block folder and do the same. Follow these steps when you do not have the original project but wish to upload the program for backup purposes. In the next screen, fill in the slot the CPU is in this is always 2 for S and the node address of the communication port on the CPU. After clicking OK, the whole contents of the PLC including all blocks and hardware configuration will be uploaded into a new station in the project.

While this project contains no documentation, it can be used as a backup to download later if needed. System diagnostics, r eport system fault, integrated process fault diagnostics in S7-Graph. Sound familiar? Have you suddenly found changes that have been made in the PLC but not in the offline program?

Nobody knows what happened. The problems stem from the flexibility of the software both for downloading and editing the online program. How to solve this problem? After that is a step by step best practice when editing programs. Offline program — The program that is stored on the hard disk of the computer. This will contain the documentation. Download — The act of taking the offline program on the computer and downloading it into the PLC.

Upload — Taking the program in the PLC and bringing it up to the computer. Doing this without having the associated offline program open will cause a loss of documentation. Save — Stores the open block onto the hard drive. Note that this only saves the opened block and not any others that are concurrently open. Nodes — Refers to any programmable device in our case a PLC in the network which will have its own unique address. The best practice is to make sure you are working from an offline file.

Of course, this assumes that you have a good working copy to begin with. So where do some people get lost? Here are some common mistakes and their warning signs.

This is an example void of documentation. Notice the local parameters all say TEMP. There are no comments or titles. The properly documented copy looks like this The Display Accessible Nodes selection under the PLC menu is a handy way to see what is connected to the network but it should never be used to open blocks. Opening blocks from here uploads it straight from the PLC and produces the warnings dialog boxes shown above.

Once a project is open and a connection to a PLC is established then selecting the Online button menu View Online brings up a similar project tree showing the contents inside the PLC. The window title bar is highlighted in blue to indicate its online status. Working from this window presents less of a danger for losing documentation but it is confusing and could lead to problems. For instance if a block is renamed offline and then the old one is opened online then it will have no associated documentation.

The proper way to view a block online is to open the block and select the Establish Connection to Configured CPU icon. Just make sure what you are viewing has been downloaded to the PLC. Essentially this puts you in the same place as pitfall 2. Always working from the offline copy will make it less likely to screw up. Opening up a block from the accessible nodes window is always a no-no. Likewise, opening a block from a window that has a highlighted blue title bar will also cause potential problems.

Avoid the pitfalls and keep that documentation. Mystery solved. These warnings are especially crucial if you are working on real machinery. Click the General tab and press the Activate button. I couldn't find a complete listing of all the function blocks in the standard Siemens S7 Libraries so I made one myself.

It helps me get a better overview of what is available. The complete listing is also available as an Excel spreadsheet so you can sort or adjust to your needs. Otherwise known as Siemens speak. Here's a list of Siemens specific abbreviations and their meanings. The following is provided by Automation Training from their excellent Siemens Step 7 training manual. This is a really nice explanation of a difficult but important subject.

Check out their website for hands-on and online training classes. When a direct addressed is referenced by an instruction there is no question as to the location in memory. The following are examples of direct addressing:. By using the methods of indirect addressing the address used by an instruction can be varied to point to any number of locations. While this may increase the difficulty of troubleshooting, its advantage is to greatly reduce the number of networks and instructions needed to control a process.

It is also a method that must be understood to use some of the library and system function calls provided by Siemens. A pointer is always preceded by a P symbol. The pointer address may be in three different formats. The ANY data type is used to pass a parameter of an unknown or undefined data type.

Some functions in the library use the ANY data type to work on whole sections of memory. To do this, the last pointer method is used to describe an area. For example the address P DB DBX 0. When working with indirect addressing it is sometimes needed to first of all open a DB and then begin working on the address without directly referring to any one DB. This is done using the OPN instruction.

Furthermore, there are instructions to confirm that the correct DB number is opened and that it is large enough for the next operation. The first method of indirect addressing is called memory indirect addressing because it allows for a memory location M, DB or L to determine or point to another.

Two examples are as follows:. Since the bit position only goes to eight the result of P 8. Besides the regular accumulators, there are two bit address registers AR1, AR2 for storing pointers used in register indirect addressing methods.

A series of different load and transfer type instructions can be used to work with AR1. A similar set is available for AR2. The area-internal register indirect addressing method uses one of the address registers plus a pointer to determine the address the instruction is to reference.

The format is:. The address register must be previously loaded with a double word pointer without reference to the address identifier. The exact address is determined by adding the address register with the pointer. The example below shows the area-internal method using bit locations. Area-crossing register indirect addressing is similar to the area-internal method except the pointer loaded into the address register references a memory area e. This means the address identifier used before the opening bracket is not needed if referencing a bit otherwise it will be a B for byte, W for word or D for double.

The example below shows the area-crossing method using bit locations. The RLO bit stores the running logic state of the currently processing instructions. If you are used to ladder logic and struggling to understand the purpose of the RLO and STA it may help to visualize a rung like below. The OV bit is set by a math instruction with floating point numbers after a fault has occurred overflow, illegal operation, comparison unordered. The OV bit is reset when the fault is eliminated.

The Binary Result transfers the result of the operations onto the next instruction for reference. The programming is done with very simple mnemonics that can be hard to remember if you don't use it very often. These cheat sheets provide a quick reference guide for all the instructions and formatting. They are two pages long but if you can print on the front and back then they make for a nice one sheet reference. Close all other running applications, including any antivirus software you may be running.

This step involves using the Commissioning Wizard to configure the software you installed in the previous step. When your system restarts after the software has been installed, your system's hardware configuration is scanned. The Commissioning Wizard appears automatically. The number of steps required depends on the number of PC Ethernet cards or modules detected in your PC.

The more modules you operate in the computer, the more steps are required. The following points are needed:. If you have experience with Siemens then please contribute. Order the demo CD which will give you a free day trial period.

Download a free working copy of Step 7 Lite. There are differences between the regular version of Step 7 and Step 7 Lite but for learning purposes you can go along way with the free Lite version. When new hardware components are introduced, the diagnostic information is updated automatically via the engineering system HWCN. Thanks to a real-time trace function, all user programs can be precisely diagnosed and optimized and, with the aid of online functions, a great deal of information can be retrieved and exchanged and projects updated.

System diagnostics outputs all relevant information on existing errors in the system. This information is automatically packaged in messages containing the following elements:. Efficient error analysis and rapid error localization using the new uniform display concept are available for the new controllers. You can easily identify sporadic events in the system during commissioning and maintenance by visualizing the entire process using a real-time trace.

The scalable and flexible motion functionality integrated in the SIMATIC S supports the control of centrally or decentrally connected drives analog and digital.

PLCopen blocks are available for programming. Motion control technology objects TOs can be used for programming typical functions such as positioning absolute and relative , speed control, referencing, and support for absolute encoders, and for testing and reusing them as often as desired. In addition to the control tasks, these technology objects include the communication with the converter and its parameterization. The high-speed counter for S controllers enables the configuration, commissioning, and diagnosis of counter applications such as:.

The following functions are available in STEP 7 TIA Portal for implementing continuous, discrete pulse width modulation , and step controllers and for easy commissioning, thanks to automatic controller setting:.

The Compatibility Tool is a function provided by the Siemens Industry Online Support with which you can select compatible software products or check the compatibility of existing configurations.

All configuration and programming tools required for generating a safety-oriented program are integrated into the STEP 7 user interface and use a common project structure. To do this, they require high-performance software that is as efficient, flexible, and reliable as possible, both now and in the future.

STEP 7 Professional is delivered with a floating license that allows you to install the software on as many computers as you like.

The number of existing licenses determines the number of computers the software can be used on at one time. Existing licenses for earlier versions of STEP 7 Professional can be updated to the current version by means of an upgrade package. STEP 7 Basic is delivered with a floating license that allows you to install the software on as many computers as you like.

Existing licenses for earlier versions of STEP 7 Basic can be updated to the current version by means of an upgrade package. STEP 7 Safety Basic is delivered with a floating license for the failsafe S F Basic Controllers and allows you to install the software on as many computers as you like.

Existing licenses for earlier versions of STEP 7 Safety Basic can be updated to the current version by means of an upgrade package. At siemens. The offering covers all important areas ranging from a general overview to the functions of TIA Portal, as well as technologies and applications such as motion control and energy management. Learn more. Within the framework of Online and Technical Support, Siemens Industry offers a wide range of services.

Online Support, Technical Support Siemens Industry's spare parts services are available worldwide and provide smooth and fast supply of spare parts — and thus optimal plant availability. Further education for all Siemens industrial products - directly from the manufacturer, individually, with the latest methods.

You want to discuss your specific challenges with us or are looking for the right project partner? Contact our regional offices — we are looking forward to hearing from you!

Intuitive and efficient engineering — from the microcontroller to the PC-based controller. Do you always need the optimum configuration for planning your project? Of course you do!