12/15/2014 4:58 PM | ||||||||||||
Joined: 9/27/2006 Last visit: 9/20/2024 Posts: 12282 Rating: (2684) |
Hello PCS 7; Profibus communications on the S7-400H side require a specuial interface module. The redundant CPUs each have a Profibus-DP master interface (or you might use one CP 443-5 in each rack for the same purpose), but the ION meters only have a non-redundant Profibus interface (as most existing Profibus slaves). To enable switching from one DP-master to another (in case of a loss of the S7-400H rack, for any reason) you must use what is known as a Y-Link. This module acts as an interface to each redundant master, and sets up a Profibus line to a number of non-rerdundant slaves. see the attached picture for an illustration. Now there are 2 things you must be aware of when using a Y-Link: 1. the Y-link can only be configured as a slave from the point of view of the redundant DP-masters, and all the slaves behind iot (in your case your ION meters) are hidden from these masters. Thee single slave that is the Y-link can only transmit up to 244 bytes (OUT/IN) to the redundant masters. So you must calculate how much data you plan to transmit per ION meter, and limit the number of meters behind a Y-Link so you do not exceed the lkimitations. You might have to setup more than one Y-Link in your project to connect all 25 meters. 2. the hardware of the Y-Link includes 2 IM-153-2 interface modules, one Y-Coupler and active bus modules (with a special rack to support these). Have a look at the following documents (the redundant IM 153-2 bundle will provide the basic elements for the Y-Link): SIMATIC Bus links DP/PA coupler, active field distributors, DP/PA Link and Y Link 2.6 Y link Application The Y link is intended for the redundancy mode, for example on S7-400H. - Operating principle ● The Y link is slave on the higher level DP master system and acts as a proxy for the nodes connected on the underlying bus system (DP slaves). ● The Y link forms an independent underlying bus system that is decoupled from the higher level DP master system in terms of communication. 5.5 Mounting the Y link -Configuration with bus modules The Y link must always be configured with bus modules. Components required ● Rail for configuration with active bus modules ("Rail for module change during operation") ● 2 x IM 153-2 ● Bus module BM IM/IM ● Y coupler ● Bus module BM Y coupler Which active backplane bus modules do you need when using the DP/PA link or Y link?
Hope this helps, Daniel Chartier |
|||||||||||
Last edited by: dchartier at: 12/15/2014 5:01 PM |
||||||||||||
Follow us on