9/3/2011 4:18 PM | |
Posts: 99 Rating: (0) |
is it true the GSD file is loaded to the class 1 DP master only? thanks |
9/4/2011 3:03 AM | |
Joined: 9/27/2006 Last visit: 4/17/2024 Posts: 12256 Rating: (2664) |
Hello Abdo; Actually, the contents of the GSD file are never loaded to the Profibus-DP class 1 master, but they are used by the software that the class 1 master uses to configure the slaves it will exchange data with. A GSD file is a simple text file (formated in a standart way) provided by a manufacturer of automation equipment that has built a Profibus slave, spelling out the different parameters (bus speed, data packet size...) that the slave allows, and that the class 1 master has to adapt to if it wants to connect to that particular slave, That configuration software can be the Simatic ManagerHWConfig editor (for S7 PLCs), Com Profibus (for S5 and Siemens/TI505 PLCs), Sycon (for Modicon) and many other packages from different manufacturers. Have a look at the following article, from an automation magagzine, written by an Acromag employee; Acromag has developped a wide range of Profibus-DP and -PA interfaces and are considered experts in the field. http://www.automation.com/resources-tools/articles-white-papers/fieldbus-serial-bus-io-networks/introduction-to-profibus-dp Note these quotes from the article: they explain how theProfibus-DP slave's GSD file is used by a class 1 master to define the parameters of the cyclic data exchange with its assigned slaves: A class 1 master device is normally a central programmable controller (PLC), or a PC running special software. The class 1 master sets the baud rate and the slave's auto-detect this rate. The class 1 master handles the data exchange with the slaves assigned to it, and acts as the main controller for the exchange of I/O information with its distributed slaves, cyclically retrieving user I/O data according to a defined message cycle. A master can communicate actively with its assigned slaves, but only passively (upon request) with another class 2 master device.
The length (and timing) of the I/O data to be transferred from a single slave to a master is predefined in the slave's device data base or GSD file. The GSD files of each device connected via the network (slaves and class 1 masters only) are compiled into a master parameter record which contains parameterization and configuration data, an address allocation list, and the bus parameters for all connected stations. A master uses this information to set up communication with each slave during startup. Hope this helps,
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Last edited by: dchartier at: 9/4/2011 3:04 AM |
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