Siemens C79000-G8976-C156-07 quick start Cycle Time Parameter, Protocol

Models: C79000-G8976-C156-07

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B Description of the PROFINET Configuration File

The Cycle Time Parameter

This parameter will be configured in the user interface as of SIMATIC NET V6.1 with STEP 7/SIMATIC NCM PC V5.2 and higher.

Parameter

Meaning

 

 

Syntax

[PROTOCOL]

 

CycleTime=100

 

 

Purpose

The scan cycle time specifies how often the OPC

 

server updates the values of the OPC items using

 

a new communication job.

 

 

Default

100 ms

 

 

Relationship between Cycle Time and Update Rate

The “UpdateRate” parameter that can be set in the

 

user program specifies the shortest possible

 

interval for checking the values of the OPC items of

 

an active OPC group. When this interval elapses,

 

the server checks whether or not the values of the

 

active OPC items have changed.

 

The update rates used by the OPC Server for

 

SIMATIC NET are multiples of the cycle time

 

specified here during project engineering. The

 

maximum update rate (shortest interval) is the

 

same as the cycle time.

 

 

Relationship between the Set Protocol-specific

Since the SIMATIC NET OPC Server can use

Cycle Times

variables of different protocols at the same time,

 

the maximum update rate of the OPC server is the

 

highest value set for the scan cycle time for the

 

active protocols (those for which connections are

 

configured).

 

 

Example

A scan cycle time of 100 ms is configured for

 

PROFInet. No other protocol is being used. 100 ms

 

is used by the OPC server as the minimum update

 

interval. The S7 protocol is now added and the

 

scan cycle time configured for this protocol is 500

 

ms. Result: The OPC Server now uses the value

 

500 ms as the minimum update interval for all

 

protocols.

 

 

288

Commissioning PC Stations - Manual and Quick Start

Release 5/2005

C79000- G8976- C156 - 07

Page 288
Image 288
Siemens C79000-G8976-C156-07 quick start Cycle Time Parameter, Protocol