If I have a controller (Arduino or PLC) and want to have a high power motor and low power sensors on the same circuit, what is the best way to approach this?
By having say a 24V power supply with enough amps for everything on the circuit that has to be ran simultaneously?
I see that a relay might be used between the controller and the motor, would another relay be attached to the circuit for the sensors or are resistors used? Thanks.
Working with a 24V power supply and you need the 24V for motors and lower power for other devices, I'd find a switching regulator that will provide device power from the 24V.
A buck converter down to 5V from 24V will be mainly immune to voltage dropouts and droop on the 24V rail so its a reasonable approach.
Do you have a particular motor, power supply and sensors in mind?
BTW the cheap LM2596-based buck converters on eBay seem to be pretty reliable in my experience, they
have a ten-turn preset pot to set the output voltage - I've used a number in various projects. If you need
very clean 5V rail I'd suggest buck converting down to about 7.5V and feeding that to Vin or the barrel jack
of the Arduino - then the on-board linear regulator can provide 5V for sensors.
MarkT:
Do you have a particular motor, power supply and sensors in mind?
I havent determined the motor size exactly yet but if I was using a 12V motor, a 3V motor and some 5V sensors etc..
Would the output voltage be 12V and then use switching regulator / buck converter to step down for each circuit?
And each switching regulator has an output amps, does this need to exactly match what needs to draw from it at each step?
If you have a 12V motor use a 12V power supply.
Make sure each power supply is capable of enough amps for the load it is powering.
If your load takes 2A then a 3A, 5A or 1000A supply would all work just fine, although the latter would
strain your wallet! Power supplies provide a voltage, loads draw current - so long as the load doesnt
draw too much current from the supply, the supply will cope.