the power supply is to feed only digital devices but there are some communiction links involved rs232/485 and dh+? i assume it should be ok with these
thanks for the reply
Since your dealing with PLCs which are probably in a closed box, a switcher will generate much less heat than a linear of similar ratings which is a plus.
Linears are quieter but switchers have come a long ways.
You can get ones for <1% ripple & noise at less than $1 per watt these days. For digital, this is not a problem.
For analog, you can always add a small linear regulator off the switcher output to quiet things down.
Linears need more power and take up more space. Switchers are usually 75% - 90% efficient, so they need less power and space.
Switchers generate more EMI but if they have CE Mark they conform to a least 40 dB of shielding.
In rare cases, the resonant point in the load and switcher frequency need to be taken into account, though for most apps the switcher frequency is up there in 20kHz - 500 kHz depending on the size.
Some real cheap switchers need minimum load.
Also, in rare cases, the loop response of the switcher may be important.
I've also seen plenty of switchers that have the CE mark and FCC, but in fact are broadband noise generators that will fail you at any test range.
Always check, never assume with those things.
