Siemens SIMATIC NET Spécifications télécharger pdf (Page 61)

Chapter 5. About the SI7 I/O Driver 51

Feature: Using Exception-Based Processing

Intellution version 7.x drivers support exception-based processing when used with

FIX/iFIX products for process control. With exception-based processing, the

software application only processes data when the data changes beyond a datablock’s

dead band.

Exception-based processing also applies to database blocks. You can enable

exception-based processing for many blocks in the process database. Once you

enable this feature, the I/O driver reports any data change that exceeds a datablock’s

dead band to the FIX/iFIX Scan, Alarm, and Control (SAC) program. This program

resides in the background and works to maintain the process database continuously.

Upon receiving notification of an exception, SAC polls for information on the

affected database block and updates that block’s value.

IMPORTANT: Do not configure an exception-based database block and time-based

database block to reference the same I/O address. If you do, the time-based block is

updated when the exception deadband is exceeded and is not updated based on the

block's scan time

To configure a database block for exception-based processing

[1] Start the Power Tool and select the datablock you want to modify.

[2] Enter a value in the Deadband field. For a digital block, enter a dead band of

[3] Start Database Manager.

[4] Double-click the block you want to modify from the program’s spreadsheet or

select Add from the Blocks menu and select the type of block you want to

create.

[5] Enter the datablock’s address in the I/O Address field of the database block.

[6] Enter E in the Scan Time field of the database block.

If you have many database blocks, exception-based processing can help reduce the

demand on SAC.

NOTE: Analog Register and Digital Register blocks in process databases do not

support exception-based processing. In addition, the SI7 7.x driver does not support

using the Text block with exception-based processing, S7 Timers, or S7 Counters.

1 2 ... 56 57 58 59 60 61 62 63 64 65 66 ... 267 268

Pas de commentaire

Siemens SIMATIC NET Spécifications Page 61