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, 08-11-2025, 06:30 AM

I am working on a board,that's s using full bridge motor driver MCU some sensors,terminal blocks and relays and switch.I m new to motors so can anyone guide if I have to have emergency switch with relay that is used to stop yhe motor either through HW and SW mix how can it be.
Or any ref which I can follow.
Thanks

QDrives , 08-12-2025, 11:15 AM

That depends on your safety analysis.
Product standards -> General electrical safety standards (like ISO 13849 or IEC 61508) -> General safety standards (like ISO 12100) -> Guide on using machine directive.
The product must comply to rules and regulations, like the Machine Directive in the EU.

, 08-12-2025, 02:59 PM

So basically I want to use a connector with electronic switch and relay such that something happens in the circuit the supply to whole of the system stops.
Is thr any refrence I can check or refer to it or any guidance in this anyone can share.

QDrives , 08-12-2025, 09:42 PM

For the hanging MCU you can look at a (external) watchdog IC. But do consider that you may just need the internal watchdogs in the STM. It has two.

Whenever safety is involved, as the word "emergency" implies, it is best to follow the safety standards.
Because it is not just an alternative path to switch off, but you also need to know that it is safe to turn on.

, 08-13-2025, 03:27 AM

Thankyou @QDrives but can you also help if i have to use a 5 pin relay with e switch how will be connections be as I could not get any ref.

QDrives , 08-13-2025, 02:20 PM

First off - how save does it need to be? PLb? PLc (SIL1)? PLd (SIL2)? PLe (SIL3)? Or SIL4?
To answer this, you need to state what kind of product it is, what the circuit does, what dangers can happen in case of failure, etc.

Is the WDT in the MCU enough to get the safety level?
How easy can you test?

In part safety is easy, but you need to know the basics and that may be a difficult step.
I suggest you get a copy of ISO 13849-1 standard and read that.

, 08-13-2025, 04:21 PM

Ok Thankyou