Phidgets Forums

I have a VINT Hub Phidget, and I want to control a relay board. I read the web page on the open collector output. https://www.phidgets.com/docs/Open_Coll ... put_Primer.
The relays will turn on an external power supply. If there is no power to the relay board, or the VINT Hub, I want to make sure the external supplies can't run. (due to the various steps during startup....). Hence I want to use the NO (normally open) contacts on the relays. But, per the web page, if I use the NO contacts, when the program starts up, but *before* the digital output is turned on, the NO contacts will be closed and the supplies enabled.
Is there a way to arrange this so I can use the NO contacts?

Do you mean using a VINT Hub port in digital output mode to control a relay board? The VINT Hub ports are not open collector digital outputs, they are push-pull outputs.

-Patrick

ok, my mistake. Maybe I got onto that page and assumed that the phrase "digital output" applied to anything with a digital output.
But if I'm using the digital output of the VINT hub, can I just drive it directly? Do I just skip the pull-up resistor?
The relay board is actually a 12V board, but the relays seem to switch over when Vinput is anything over 1.5 Volts.

You do not need a pull up resistor when using the Digital Outputs from the HUB0000 ports. They are push-pull outputs that will provide 0V when off and 3.3V when on, no external hardware required.

For completeness, the primer that applies to the outputs on the HUB0000 is:
https://www.phidgets.com/docs/Digital_Output_Primer