Automation– and Drive Technology- SCE Training document for the company-wide automation solution Totally Integrated Automation (T I A) MODULE B4 Data blocks T I A Training document Last revision: 02/2002 Page 1 of 18 Module B4 Data Blocks
Automation– and Drive Technology- SCE This document was provided by Siemens A&D SCE (automation and drive technology, Siemens A&D Cooperates with Education) for training purposes. Siemens does not make any type of guarantee regarding its contents. The passing on or duplication of this document, including the use and report of its contents, is only permitted within public and training facilities. Exceptions require written permission by Siemens A&D SCE (Mr. Knust: E-Mail: michael.knust@hvr.siemens.de).
Automation– and Drive Technology- SCE PAGE: 1. Forward................................................................................................................. 4 2. Notes for Data Blocks.......................................................................................... 6 3. Generating Data Blocks ......................................................................................
Automation– and Drive Technology- SCE 1. FORWARD The module B4 is assigned content wise to Additional functions of STEP 7- Programming.
Automation– and Drive Technology- SCE Required hardware and software 1 2 3 4 PC, Operating system Windows 95/98/2000/ME/NT4.0 with - Minimal: 133MHz and 64MB RAM, approx. 65 MB free hard disk space - Optimal: 500MHz and 128MB RAM, approx. 65 MB free hard disk space Software STEP 7 V 5.x MPI- Interface for the PC (e.g. PC- Adapter) PLC SIMATIC S7-300 with at least one digital in- and output module. The inputs must be lead through a functional unit.
Automation– and Drive Technology- SCE 2. NOTES FOR DATA BLOCKS Data Blocks (DBs) can be used by your program to save data in the CPU. Your hard disk contains up to 8 KBytes ( 8192 Bytes ) space. There are two types of data blocks. Global DBs, where all OBs, FBs and FCs read all saved data or can even write in the DB and local instance DBs, which are assigned a particular FB. In the DBs, different data types (e.g. BOOL or WORD ) can be saved in arbitrary order.
Automation– and Drive Technology- SCE 3. GENERATING DATA BLOCKS Data blocks are generated and opened like program blocks in the tool LAD,STL,FBD: Program blocks. They serve e.g. for the saving of data and system states. In the following text, the generation of a simple example is described by the use of a global data block: Thereby values should be chosen with the switches 'S0' to 'S7' and displayed on an output module ‘Display‘.
Automation– and Drive Technology- SCE In order to generate this program example, the following steps must be followed (Thereby the program is dispensed with the creation of the hardware configuration): 1. Call SIMATIC Manager with a double click ( ® SIMATIC Manager) 2.
Automation– and Drive Technology- SCE 3. In the name path, create the project with the name Testproject_DB. (® ’Testproject_DB’ ® OK) 4. Insert a new S7-Program ( ® Insert ® Program ® S7-Program).
Automation– and Drive Technology- SCE 5. Highlight the folder Blocks. (® Blocks) 6. Insert Data Block ( ® Insert ® S7 Block ® Data Block).
Automation– and Drive Technology- SCE 7. Enter the number DB10 for the data block and accept with OK (® DB10 ® OK). 8. Open the data block DB10 with a double click(® DB10).
Automation– and Drive Technology- SCE 9. Acknowledge the type of data block. ( ® Data Block ® OK ) Note: Forward T I A Training document Last revision: 02/2002 Data blocks with an assigned FB are automatically displayed by the call of your associated FB. It makes no sense to create this alone. Data blocks with assigned user defined data types (UDT) are data blocks, whose structure was already assigned in this UDT.
Automation– and Drive Technology- SCE 10. The Data Block is generated with a symbol Name. The Type, an Initial value as well as a Comment (optional) are entered. The address is automatically generated and cannot be altered. The data block can be saved and downloaded into the PLC . The mode switch on the PLC must be on STOP! (® Name® Type ® Initial value ® Comment ® Symbolic name which is referenced to the absolute address. Desired data type (see below) for your data element.
Automation– and Drive Technology- SCE Data in a data block must be determined through data types.
Automation– and Drive Technology- SCE 11. Values should be modified in a data block. It is not adequate to modify them in the field Initial value . This is only possible, when one switches to the Data View under View ( ® View ® Data View). 12. Now a new value can be entered in the field Actual value and saved onto the hard drive with as well as downloaded into the CPU with Forward T I A Training document Last revision: 02/2002 Notes Page 15 of 18 ( ® Actual value ® ® ).
Automation– and Drive Technology- SCE 13. In order to generate the program with the accessible data elements, the OB1 must be opened through a double click in SIMATIC Manager ( ® SIMATIC Manager ® OB1). 14. Then accept the setting with OK (® OK ).
Automation– and Drive Technology- SCE There are three possibilities to access the data: 1. Direct address access: One can access one data element in a data block with the following instructions: Example: L DB 20. DBB2 L DB 22. DBW4 A DB 2. DBX5.6 Load data byte 2 from DB20 into ACCU 1 Load data word 4 from DB22 into ACCU 1 Carry out an AND- logical operation with data bit 5.6 from DB2. 2.
Automation– and Drive Technology- SCE 15. With LAD, STL, FBD: Program blocks, you now have an editor that give you the possibility to generate your STEP 7-Program. The schema for the selection of the data element through the button is shown for the first three inputs as specified below. If the organization block OB1 is not generated for all switches S0 to S7, it should be saved and downloaded into the PLC . The mode switch of the CPU must be on STOP! ( ® ® ) 16.
