Support Forum

Share your projects and post your questions

Register   or   Sign In
The Forum

Low trigger relay issues

The IO Pi Plus is a 32 channel MCP23017 GPIO expander for the Raspberry Pi

15/05/2024

Posted by:
nicusor.stoica

nicusor.stoica Avatar

I am using a low level trigger relay board and when the power is lost the pins go low for a small period of time then everything goes back to normal, why is that happening? Or should I switch to a high level trigger relay board?

15/05/2024

Posted by:
nicusor.stoica

nicusor.stoica Avatar

I meant to say when the power is lost and the system boots back up. I could post the code if necessary.

15/05/2024

Posted by:
andrew

andrew Avatar

Hello

If the power is lost the MCP23017 IO chip will reset to its default state with the pins set to inputs, so any pin that was outputing a high level voltage will go to 0V.

Using a relay board with high level triggering or putting an inverter between the outputs on the IO Pi Plus and your relay board should fix the problem.

15/05/2024

Posted by:
nicusor.stoica

nicusor.stoica Avatar

Quote from andrew
Hello

If the power is lost the MCP23017 IO chip will reset to its default state with the pins set to inputs, so any pin that was outputing a high level voltage will go to 0V.

Using a relay board with high level triggering or putting an inverter between the outputs on the IO Pi Plus and your relay board should fix the problem.


Thank you so much !

Sign in to post your reply


Note: documents in Portable Document Format (PDF) require Adobe Acrobat Reader 5.0 or higher to view.
Download Adobe Acrobat Reader or other PDF reading software for your computer or mobile device.

Home

Shop

Learn

Forum

FAQ

Contact

0 item

Your cart is empty

Please browse our shop to order from the wide range of Raspberry Pi boards and accessories.

Subtotal:£0.00
View Basket Continue to Checkout