Question for the smarter people, is there a power supply that i could use that would take 24VAC or 24VDC and step down to the 5V needed by the arduino?
The devices i want to interface with, the old versions run on 24VDC, and the new versions run on 24VAC.
Basically old versions do step down/convert from 120vac down to 24vdc on board and accessible terminals to power accessory devices has 24vdc.
Newer version uses a 120vac -> 24vac transformer, and the terminals for powering any accessories has 24vac.
I was hoping to use 1 power supply between each version so that i dont need to unhook anything on arduino side to power everything up.
(Note:actual VDC is 22-26VDC depending on what year old logic board is from. VAC is 24-28 on newer boards)
Are you wanting to build one or to buy one? Any board that has a bridge rectifier as the first component will either rectify the 24 VAC or will pass through the 24VDC. I have such a board in my box of stuff that works that way for up to 12 volts, so there may be ones around to do it for 24 volts.
You **could** use a bridge rectifier, capacitor and switchmode "buck" converter to generate the 5 V. Obviously no part of the 5 V logic system could be directly connected to the 24 V AC system but would need to be isolated via relays and optocouplers.
It would however, be far easier and more effective to simply provide a small mains supply for the 5 V using a switching converter module.
OK. I admit I misunderstood. I thought it was an option of using either 24VAC or DC input
Those converters have a max input voltage of 28VDC, so a 24VAC peak rectified would exceed that.
Any bridge rectifier that can handle the voltage and current will work. Easiest are the black epoxy units with 4 legs. Just wire in front of the bucking regulator board. You should be able to figure that out and get it working in no time.
24 V is quite low but some mains power supplies may run on this and even provide some current. As a bonus you will get galvanic isolation.
Be careful of you decide to use this: the power supplies may generate high voltage internally even powered from "safe voltage". Of course you are safe as long as you don't open the supply package.
These devices are powered by different mains depending on location etc. 1 PH 120vac or 240vac. 3PH 208vac, 460vac, 575vac.
This is why i was looking to power off of the 24v instead of mains.
I am planning on enclosing while device so that i have only the wires coming out of a 3d printed case that i have to hook up. (2 wires for 24vdc/24vac, 12 wires to connect to terminals/spade connectors/wire nuts for monitoring)
Note that this is all just for monitoring for troubleshooting etc. So the device would be added/removed from lots of units over time, which is why i was trying to get/make a supply that i wouldnt need to change between 24vdc and 24vac
If120VAC is available/accessable, a 5V power supply is the easiest solution. If you have a handy 120V outlet (or if you add one) you can plug-in USB "charger" (available everywhere if you don't already have an extra).
Not able to have 120vac all the time. And the plan i had would be to leave it connected for a couple of days to gather and save diagnostic data, and then i would pull out the device to go through all of the data
Truly remarkable! 