8/2/2020 2:59 PM | |
Joined: 9/27/2006 Last visit: 9/4/2024 Posts: 12282 Rating:
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Hello DPCS; Profibus and Profinet allow safety implementations because they have developed ProfiSafe, an extension of their protocol accredited by IEC61508. Among other techniques they use a "black channel" design that separates the Safety data from regular data on the transmission, ensuring stable and repetitive timing of Safety exchanges with high priority. Look up ProfiSafe in the Profibus.com download pages to have more details. https://www.profibus.com/download/profisafe-technology-and-application-system-description/ Modbus does not have a regulatory body to implement such developments, so you would have to depend on 3rd-parties to propose Safety transmissions between a Modbus client and its Safety servers. There are interesting documents circulating on the web discussing OpenSafety, an open-source project proposing a fieldbus-independant Safety extenstion to Modbus TCP (among other protocols). https://en.wikipedia.org/wiki/OpenSafety https://sourceforge.net/projects/opensafety/ https://control.com/forums/threads/modbus-for-safety-systems.22055/ Unfortunately, there seems to be a very small number of manufacturers proposing hardware supporting OpenSafety B&R being one of the few I can locate (and they have implemented it on Powerlink, not Modbus TCP): https://www.br-automation.com/en/technologies/opensafety/ https://www.ethernet-powerlink.org/fileadmin/user_upload/Dokumente/Downloads/POWERLINK_FACTS/POWERLINKFacts_01_10_Englisch_Edition__1_.pdf Still, it remains a very interesting subject, we will simply have to keep our interest open until someone actually develops a certified application on Modbus TCP. Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 08/02/2020 15:00:55 |
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8/3/2020 8:28 AM | |
Joined: 12/16/2018 Last visit: 6/16/2024 Posts: 67 Rating:
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Thank you very much for your helpful explanation |
Last edited by: DPCS at: 08/03/2020 08:46:24 |
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8/3/2020 5:10 PM | |
Joined: 9/27/2006 Last visit: 9/4/2024 Posts: 12282 Rating:
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Hello DPCS; Could you explain exactly what you are expecting to find In Siemens dociumentation for ProfiSafe? As it is, your request is not clear. Profisafe is a Safety extension of Profinet networks between a Profinet I/O controller (Safety) with I/O devices in the field (Safety modules). Switches, cables or IE/PB gateways are not considered as active elements of Profisafe, as shown in the screenshot below, extracted from this ProfiSafe description: The only exception I know to my last statement is wireless transmissions of ProfiSafe signals: since wireless is not deterministic, it requires special hardware to ensure that Safety data is transmitted within ProfiSafe specs; Siemens proposes the Scalance W-700 for that explicit purpose: ◾ iPCF with SCALANCE W-700 for required deterministic and fast roaming in PROFINET IO applications as well as wireless transmission of PROFINET with PROFIsafe, e.g. for emergency stop function https://support.industry.siemens.com/cs/ww/en/view/109766393 Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 08/03/2020 18:23:38 |
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