6/17/2014 9:28 PM | |
Joined: 9/27/2006 Last visit: 8/14/2024 Posts: 12277 Rating: (2680) |
Hello Bech; We can probably help you out in the Profibus section of your topology, connection between the ABB PLC and HMI would be better defined by ABB support. Profibus-PA is not an independant network, it acts as a sub-network for a Profibus-DP master, You need a gateway between PA and DP, either a DP/PA coupler or a DP/PA Link, because the physical layer is different between DP (based on RS-485) and PA (Manchester, Bus-Powered) and bexcause the byus speeds are different: DP can operate up to 12 MB, PA is limited to 31,35 kB by the FISCO standard for non-inecendiary electronics. Start with information on Profibus,com: PROFIBUS PA User and Installation Guideline It would be useful to know what module (manufacturer and model) you are planning to use as a "converter/coupler" between DP and PA, it would make the reply simpler. In any case, you will need a gsd file for each instrument you plan to connect to the PA network: Definition of GSD File for use with Profibus The instrument gsd file will be provided bythe instrument manufacturer. If you happen to be using a Siemens instrument, you can find the gsd file here: Now, if you are using a DP/PA coupler, you can directly import the gsd file in your Profibus-DP master's configurator; I believe ABB uses Sycon, look in the online help to know how to integrate the different gsd files. If you are using a DP/PA link, things can be a little more complex, please advise so we can give you more details.
When I insist on the differences between a coupler and a link, it is because of the impact this has on bus speeds.If you use a link, you can operate the DP network at itsnormal speed, while the PA slaves are polled at PA speeds (31,35 kb). If you use a DP/PA coiupler, the whole Profibus network must be brought down to speeds allowed by the coupler. Siemens' coupler brings down the DP networkto 45,45 kb, while P&F coupler brings it down to 93,5 kB; study the manuals from the manufacturer of your DP/PA coupler. Once the PA instruments are connected and configured in the DP master, each instrument will transmit 5 bytes of data to the DP master, the first 4 bytes are the actual value in REAL format (IEEE floating-point). The last byte is a status byte for the instrument that can be used for diagnostics. See my contribution to the following thread. Need Profibus DP & Profibus PA status on HMI The addresses where you will find the actual value and status byte of your PA instruments in the AC800 PLC will be given to you in the Profibus configuration of the DP-master, You must then transfer this data to your HMI system to display them in the operating screens. See the manuals or online help from the manufacturer for more info. One last point: you will need a Profibus-PA configuration software to parametrize the different PA instruments over the network, such as Siemens' PDM, or Endress+ Hauser's Fieldcare. Have you provided for such a software in your design? Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 6/17/2014 9:44 PM |
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