Of course 110V / 230V AC input cards are just nasty, and at least in my industry are very rare to find these days except in ancient equipment.
Yes to mainly DC inputs, and all DC outputs, but most of my rack PLC projects have one 120 AC input card to monitor fused power, and if the PLC runs on a UPS to know if the incoming power has failed.
if the PLC runs on a UPS to know if the incoming power has failed.
Every UPS I've seen used in the automation world has had some kind of built in feedback showing it is active. Creative solution though, if it isn't.
Yes to mainly DC inputs, and all DC outputs, but most of my rack PLC projects have one 120 AC input card to monitor fused power, and if the PLC runs on a UPS to know if the incoming power has failed.
Lare,
i the US, new construction using higher than 120 volt controls is not allowed. NFPA 79
i cannot cite book, chapter, and verse, but it has been in the rules for quite a few years. the items that have been grandfathered in is ok, i don't know the year when it stopped.
james
Do you mean that it isn't allowed to wire 120AC first to 120VAC interposing relay and then from that relay contact side to 24VDC input card?
But instead it is allowed connect 120VAC directly to PLC 120VAC input card?
Lare,
i the US, new construction using higher than 120 volt controls is not allowed. NFPA 79
i cannot cite book, chapter, and verse, but it has been in the rules for quite a few years. the items that have been grandfathered in is ok, i don't know the year when it stopped.
james