Can anyone tell me how to connect a sensor to the 4-20mA input on the comms board.I need temperature and all 4-20mA temperature sensors I'm familiar with are 24 VDC not 1.8
On Monday, February 1, 2021 at 7:29:46 PM UTC-5 Dennis Bieber wrote: > On Mon, 1 Feb 2021 15:46:51 -0800 (PST), in > gmane.comp.hardware.beagleboard.user Dwayne Zimmerman > <dzimmermanpas-re5j...@public.gmane.org> wrote: > > >So the pull down is to keep the voltage under 1.8 correct? My confusion > is > >I have one screw per input, 4-20mA is two wire where is the other half of > >the circut? > > > > I suspect the pull-down is only ensuring that the floating voltage is > tied to 0V; feeding anything with a voltage over 1.8V will still fry the > input. And since 0V likely also means 0mA, it indicates a fault condition > in the loop. > > > https://www.fluke.com/en-us/learn/best-practices/test-tools-basics/process-tools/what-is-a-4-20-ma-current-loop > > https://www.predig.com/indicatorpage/back-basics-fundamentals-4-20-ma-current-loops > {Many others| > > The input to the BBB likely needs to consist of a current->voltage > tranform, so the ADC can measure the voltage corresponding to the current. > Which might be built-into the cape (I've not looked at it). > > > -- > Dennis L Bieber > > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/5fd03d5f-b21f-43b8-b3d3-ae464ff8d1bdn%40googlegroups.com.
