9/28/2021 9:51 AM | |
Joined: 8/21/2018 Last visit: 10/7/2024 Posts: 88 Rating: (15) |
Any ideas ? |
9/30/2021 11:50 AM | |
Joined: 5/28/2008 Last visit: 10/7/2024 Posts: 4515 Rating: (839) |
Hi, There are many types of Terminal Units. Some of these terminal units have Auxillary terminals, And others don't have. Please have a look here: https://realpars.com/et-200sp-base-unit/ For better understanding, please see the block diagram of your BU. You can found it in the following manual: SIMATIC ET 200SP Manual Collection And flow charts for the selection of BU can be found on pages 41-43. And here's below one example for BU A0 Hope this helps. |
Ayman Elotaify |
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9/30/2021 4:05 PM | |
Joined: 5/28/2008 Last visit: 10/7/2024 Posts: 4515 Rating: (839) |
Hi,
The purpose is to use auxiliary output. As an example. Suppose you need 1 DO to energize a relay or contactor. And need to wire the same DO to another actuator or indication lamp. then you can take it from AUX terminals.
First, using BU with AUX terminals is not only suitable for fail-safe modules but also for standard and can be used for the same purpose I told above. If you mean to increase Availability, AUX terminals are not the right solution. But you have to go for redundancy. If you mean to increase Safety (like SIL3) for instance, I will give you example for 24 DI-Fail safe module (ET-200M) - You can achieve SIL 2 by using all 24 DI channels. And to achieve SIL 3, You have to wire only 12 DI Channels and other 12 Channels should be wired to the same as well. So, it's a different story. AUX contact is exactly like 2 terminal blocks. It's a feature, take it or leave it. For your module and to achieve SIL3, you have to follow the configuration examples here in the following manual (Section 5 - Pages 30 & 31). You will need to use 2 relays for each DO channel. Not necessary to use the AUX terminals.
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Ayman Elotaify |
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