W5100 hangs when i switch 220v loads

Question

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. I energizing the relay with a transistor and used a 1n4007 on relay coil. Please help me.

electrobrain · Answer

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.

peter · Answer

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.

electrobrain · Answer

when relay turn on/off, Please check surge from relay. 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.