We have an application for the MultiTech IP67 Base Station with multiple VolleyBoast Endpoints. Our key requirement:
The endpoint spec sheet describes a Digital Output as “1 open drain” of “24 V, 1A max applications.” Does that mean the endpoint can power a 12V light that draws 20ma?
If YES, we will order a base station and 8 endpoints immediately.
Thanks,
Dan
Hi dancurtin,
Welcome to the Tech Forum.
Just to clarify, to which specific part number are you referring? From what you describe, it will most likely work, but I’d like to check the documentation of the specific part to verify.
However, in general, an “open drain” output means that the output will sink, rather than source current. This means that it requires an external power supply of no more than 24V, and in your case, you would apply 12V to the “+” contact of your light and you would connect the “-” side to the open-drain output of the MultiTech device.
See this Forum post for further explanation of how “Open Drain” outputs work.
Wow, thanks for getting back to me so quickly!
The digi-key part number is 2881-VOBOGP-1-ND,
VolleyBoast LoRaWAN Universal I/O End Point
Yes, it can handle up to a 24V load at up to 1A, so it will have no trouble with your 12V 20mA light.
For connection reference, replace the “R” in the schematic below (taken from the link I gave previously) with your light. When the internal MOSFET is off, the voltage at the output will be 12V (so no current across the light). When the MOSFET turns on, the “Output” voltage will drop to just above 0V, which will allow current to flow and turn on your light.
As an aside, if you are using an LED for your light source, be sure it is designed for 12V and not just 2V to 3V. If it is designed for 12V, it will probably have an internal resistor to limit current. If your LED does not have an internal current limiting resistor, you will need to provide one externally, or else you’ll burn it out.
Great help, thanks.
