WIZnet Developer Forum

W5100 hangs when i switch 220v loads

Hi guys.
I’ve build a web server based on w5100 and mega32A.
I’ve observed all design recommendation that presented by wiznet.
Everything works well,But when I connect a Light Bulb running at 220V to relay output terminal It just turns ON once and then w5100 hangs and I will restart it manually. :frowning:
I energizing the relay with a transistor and used a 1n4007 on relay coil.
Please help me.


I think W5100 may have no problem but your gpio control function for turning on/off the relay may have some problem.

Check the again the code gpio control & gpio signal.

Thank you.

i noticed that if i away 220v wires from cat5 the situation is much better.and at this status it may hangs after 20 or 30 times relay turn ON/OFF
when i hit relay,the ping time from w5100 increased Significantly from 1ms to about 50ms or sometimes i’ve get ‘Request timed out’

However, I am sure that the problem is w5100. Because i defined 5 seconds timer for relay and after that times relay turn off properly.

I think the cause may be from relay surge.
when relay turn on/off, Please check surge from relay.
If so, you have to concider circuit for protecting(or isolation) from relay contact.

how do i check it?

i test snubber (100R and 100nF),but it does not work.
also i test varistor in place of snubber but again without any success. :neutral_face:

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