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| 1/13/2012 1:04 AM | |
Joined: 9/27/2006 Last visit: 9/14/2025 Posts: 12408 Rating:
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Hello cornbread; First point: All values transfered over Profibus are direct numeric values; there is no cause for scaling them, as for a 4-20 mA signal. If the values you read are strange, either you are not using a correct mapping or the data you are getting is not configured properly. Second point: configuring Profibus-DP comms with a Siprotec relay (with the correctcommunication interface)and any Profibus master is not easy. You require: -the correct gsd file for the relay number you are connecting to, to insert in the Profibus configurator that will help setup the network (in your case, the Prosoft configuration software for the SLC500); -the correct "mapping" information (standard telegrams used for exchanges with the relay). You must select a mapping once you have inserted the Siprotec relay in a Profibus network (in the configurator);the mappingselected mustcontain all the data you need to exchange with the relay, even if it requires a large dataspace on your CPU, and you must prepare a in/out area in your PLC that is designed to recieve all the data. Once you study the different standard mappings for your relay, you will see it gives you the values that will be transfered to the Profibus master, and the offset address where you can locate each one. Both mappings and gsd files can be found on the www.siprotec.de site, under Communications. Now, to configure the Profibus parameters (address, bus speed, mapping selection...) on the relay itself, you need Digsi4 software (and the correct serial cable to connect to the front communication connector of the relay; the Profibus RS-485 interface is found on the back of the relay). You cannot get around this requirement. We managed to work around purchasing this software by negociating a visit from a Siemens technician who would configure the relay using his Digsi4, for a fee. Just make sure this is the last thing you need to do for the implementation of the relay as a Profibus slave, or you might need more than one intervention from the Siemens tech. Digsi4 is used for other things than configuring the communication port on the relay. For example, if you need to monitor the status of the relay over Profibus, you will need to map the relay contacts to a section of the relay memory calle a Digital output. Only Digsi4 can do this for you. Have a look at the following threads from the forum, it will give you an idea of what needs to be done, and some links for more information: /tf/WW/en/Posts/51513 /tf/WW/en/Posts/50841 |
Last edited by: dchartier at: 1/13/2012 1:11 AM |
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