6/20/2018 1:37 AM | |
Joined: 9/27/2006 Last visit: 8/20/2024 Posts: 12279 Rating:
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Hello Aleix; Basically, what you are thinking of doing is called adding a tap line (also known as a "stub") to your network to connect a length of cable to your PLC with a DB9 socket. This can work, as long as you respect certain rules: you should not run the network at more than 500kB or 1,5 MB, the higher speeds will frequently cause interference to appear at the DB9 connector (due to stray capacitance, mostly from the soldering of the cable to the pins). The cable you use cannot exceed 3m, preferably be around 1,5 m max, and should have the same or proximate resistance as the Profibus cable you use in the rest of the network. Since Profibus is based on RS-485 standards, a straight cable (no crossovers) with at least 3 wires will do, (remember, cable resistance near to 120 Ohm), with pins connected 3-3, 8-8 and 5-5 (ground) on the DB9 connectors, see the screenshot below. No extra signal is required, even though some specialized equipment might indicate it. We used to build our test Profibus cables with 2 DB9 connectors, a short RS-485 cable and careful soldering. It would work well at lower speed and was a good alternative for a benchtest. Have a look at this manual, it covers all aspects of Profibus hardware and could be quite informative, even though the part numbers and equipment description may have changed since it was published. Simatic Net Profibus networks : https://support.industry.siemens.com/cs/ww/en/view/1971286 Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 6/20/2018 2:20:02 AM |
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5/12/2024 5:40 PM | |
Joined: 5/12/2024 Last visit: 7/17/2024 Posts: 3 Rating:
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It was great, thank you so much, engineer |
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