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"F" CPUs and delayed release.

Created by: @JesperMP at: 3/31/2006 3:37 PM (4 Replies)

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3/31/2006 3:37 PM	Rate (0)
@JesperMP Posts: 54 Rating: (5)	Hi, I am considering an automation concept with S7-300F CPU's and ET200S with safety modules. I think I have most things covered, but there is one question left: Maybe you know of a traditional safety-relay + door-lock combination that ensures that there is a delay from when the safety relay is activated until the door can be opened. The reason for using this is to allow rotating machinery to run down before you can open the door. The safety relay must send a voltage to the lock in order for it to unlock. The question is, if something similar is possible with the safety concept in the "F" CPU's ?
@JesperMP Posts: 54 Rating: (5)
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4/3/2006 11:38 AM	Rate (0)
Morten Bronze Member Joined: 9/27/2005 Last visit: 4/26/2024 Posts: 203 Rating: (32)	Hallo JesperMP, there is an example with F-CPU, ET 200S and Safety door: http://support.automation.siemens.com/WW/view/en/21063946 Maybe it is helpful for you. Many Greetings Morten

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4/10/2006 9:28 AM	Rate (0)
@JesperMP Posts: 54 Rating: (5)	Thanks. It looks like the main principle is possible (a door lock that can only be opened by applying a voltage form the safety system), but there is no mention of a delay time in the description you linked to, only a zero motion sensor. We have no possibility to place such a sensor on the machine. We want to set a fixed time from stop of the machine until the door can be opened. As it isnt explicitly mentioned in the example, I become afraid that it cannot be done. Does anyone know for certain that it can ?
@JesperMP Posts: 54 Rating: (5)
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4/11/2006 5:22 PM	Rate (0)
Morten Bronze Member Joined: 9/27/2005 Last visit: 4/26/2024 Posts: 203 Rating: (32)	It depends on the application. If you can assure, that after the delay time, the machine does not pose a thread, it is allowed to use Timer (Library of Distributed Safety).

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4/12/2006 10:03 AM	Rate (0)
@JesperMP Posts: 54 Rating: (5)	Thanks for the reply. Yes, we can assure that the inertia has been released after the set time. There are "normal" safety relays withexactly the samefunction. So now I know that it is possible with the F safety functions. Thanks.
@JesperMP Posts: 54 Rating: (5)
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