10-32VDC Input Power

[Engineer_UA]

Hi Guys,
For devices that come with 10-32VDC input power supplies, is there any advantage of supplying them with 24VDC versus 12VDC? Does it make a difference, or do you just go with whatever is available on site(voltage wise).
Thank you,
EE

 

[Mickey]

https://www.google.com/search?q=adv...&rlz=1CAXDKE_enUS957&sourceid=chrome&ie=UTF-8

 

[Saffa]

24V will mean smaller conductors for any higher current devices.

Loop powered devices have more available voltage at 24V. Driving a typical 250 ohm input impedance at 20mA requires 5V just for dropping across the input. That's only 7V for the device. I've seen many level sensors etc stop operating when the battery voltage drops below 11.5V.

 

[janner_10]

It makes no difference, just whatever is available.

 

[parky]

As far as I'm concerned, 24V makes more sense, an electronic device that has a range of 10-30V will work on 12V, however, there are a number of factors, running equipment that is designed for those voltages on 12V means you are nearing close to the lower end of it's working range, a drop in voltage from the normal 12V (caused by a number of factors) i.e. noise, voltage drop on cables etc. may cause false triggering. 24V is the most common supply voltage in automation for low voltage systems so there is a relatively a good supply of spares.

 

[KirkC]

It is easier to build a small 12vdc solar-powered RTU than a 24vdc one. 1 battery, 1 solar panel. Components that run on 12vdc are preferred for this type of application.

 

[TheWaterboy]

In addition to what has been said, a device that can run using 10-32V supply will convert anything beyond 10 V into lost heat. That's more of a theoretical problem than an actual one, but it's there.

 

[danw]

I vote for 24V

I'm an instrument guy. My 30 years of experience shows that

- the ability of all loop powered instruments to deliver a current signal is dependent upon the available voltage.

- many, many, many instruments would not function at 12Vdc with vendor-supplied dropping resistors on the analog input.

- Substituting a lower value resistor would likely cause HART communications on HART-enabled instruments to fail (HART requires a minimum 250 Ohms loop resistance).

- a significant number of 'instrument' failures over time are due to a failed power supply. Standardizing on a DC power supply is prudent. The VAST majority of automation DC power supplies are 24Vdc. Other voltages are 'different' and not the norm. (re-iterating Parky's comments). 12V is the oddball, 24V is the de facto standard.