PROFIBUS configuration on a PLC

[arbj 0]

Hi, I have interfaced my product (which uses a proprietary serial RS 232 protocol) to a PROFIBUS-DP network using a PROFIBUS-DP Serial Gateway device from HMS. The gateway device is identified as a slave device on the PROFIBUS-DP network. I have configured the gateway device to send and receive commands from my product. The gateway device works on the principle of address mapping. The memory in the gateway device is divided in INPUT and OUTPUT areas. The addresses in the OUTPUT data are written to by the PROFIBUS-DP master in the network, whereas the INPUT area is written to by my product. When data is written to a specific address the gateway device identifies which command is associated with the address and so generates the appropriate command to my product. The response from my product is written to the INPUT area associated with the command, thus completing the transfer of data to and from my product. My questions are as follows.. 1. Is it possible for the PLC to get a list of addresses used by the gateway device ?? I use a PROFIBUS master simulator device to test my network and this device is able to get all the addresses mapped to commands in the gateway device, but is this also possible with a PLC ?? If not do I have to provide a list of addresses used to my customer ?? 2. The gateway device has a GSD file, will this file be needed for installation on the PROFIBUS network, also how will my customers know which addresses are used for what purpose...? 3. I know MODBUS devices need to have proper documentation of various addresses used, Is this also necessary with a PROFIBUS device such as mine ? 4. Could anyone give more details on the purpose of using a GSD file, and what it contains ??? Thanks a

[kaare_t 155]

1. Most PLC vendors provide a tool for setting up the Profibus PLC module, which can import the GSD file and map the I/O commands and device type automatically, however what you have decided to use the different I/O for must be documented 2. Yes, the GSD file will normally be used when configuring the PLC, but what you have decided to do with which devices must be documented 3. You should use an I/O list to document what is used for which purpose 4. The GSD file is simply a "Device information file" that provides information about which device is connected, and what addresses are available for read/write. In general, if you know about Profibus, you only need the GSD file to configure instead of reading through a whole lot of manuals, however it is still up to the master and slave to agree which device is used to what purpose. In general, documentation is important and should be done accordingly. The GSD file defines which addresses are available for a given device, but not what it is used for so you will have to inform the customer what you have done with the different I/O in the slave and/or master. Also; GSD files are well described when searching through e.g. google!

[arbj 0]

Thanks for reply. By I/O list do you mean list of addresses used in the gateway device ? I understand that the system works on the principle of address mapping, From your reply here is what I intend to do. 1. Supply the gsd file for the gateway device to the customer. 2. Provide details of addresses used in the gateway device and mention what address is used to access which parameter of the device. Please suggest... Thanks a

[kaare_t 155]

Yes, by using point 1 and point 2 you are good to go.