Configuring Hardware and Communication Connections STEP 7.pdf

Configuring the Distributed I/O (DP)
3.12.2 Assigning Parameters for Constant Bus Cycle Time and
Isochrone Mode in HW Config
Introduction
A station consists of the following isochrone components that you have to set up in
HW Config:
• CPUs with integrated DP interfaces (i.e. CPU 414-3 DP, V3.1)
• DP interface modules (i.e. ET 200S interface module IM 151-1 High Feature)
• Distributed I/O modules (i.e. DI 2xDC24V, High Feature [131-4BB00], DO
2xDC24V/2A, High Feature [132-4BB30])
The latest updated list is available in the Internet at
http://www.ad.siemens.de/support, Entry ID 14747353.
The following sections contain information on the special aspects of configuring
these components for isochrone mode.
Setting CPU Properties
1. Select the "Synchronous Cycle Interrupt" tab.
2. The following settings have to be made for each synchronous cycle interrupt
OB:
- Specify the DP master system in use.
- Specify the desired process image partition(s)
- For S7-400-CPUs: Set the time lag. This time lag is the time between the
global control frame and the start of OB 6x. This is the time period in which
the DP master completes the cyclical data exchange with the DP slaves.
Tip: After you have finished assigning parameters to the distributed I/O
devices, be sure to let STEP 7 calculate the default value.
Configuring Hardware and Communication Connections with STEP 7
A5E00706939-01 3-87