power supply for V570

[luigi]

Hello folks,

I want to replace old hardware in a automated machine by the Unitronics V570.

The existing supply is a 24V AC transformer followed by a bridge rectifier.

So it is actualy a  pulsated DC . This supply is also used to drive some relays.

Now my question is: may I connect this pulsated DC to the supply of the V570?

Thanks

[Ausman]

You need to have a good switch mode supply for all the plc components at the very least. 

What is the coil voltage/type shown on the existing relays?  If they are 24DC then your switchmode should be driving them, too.  They need to be fitted with clamps...see the post linked at the bottom.  I wouldn't be having anything that is a "pulsed" supply coming anywhere near the plc.  If the exisiting tranny needs to remain, I would be using separate interface relays to drive things it is working and keep things well separated.   Others may disagree with this, but I never have issues with electrical noise problems because I only ever have (properly clamped) DC on/near the plc and expansions.

cheers, Aus 

clamp post: read it all

 

[kratmel]

Please note - some device use 380V to 24V transformer and do not use neutral conductor. 

Standard switch mode supply use 100-270VAC input.     Than you must use 380 to 220V transformer and standard switch mode supply.

Or use 3ph 380VAC to 24VDC industrial switch mode supply.

[luigi]

Thanks for the replies.
I will take no risk and provide a regulated 24VDC power supply from Omron.
The Unitronics output module will drive lowpower 24VDC relays (also fed by the Omron supply).
The contacts of these relays will drive the existing relays/contactors (fed by existing transformer/bridge). 
Thanks again.
Luigi