Uninterruptable power supply for Controllogix PLCs??
Uninterruptable power supply for Controllogix PLCs??
(OP)
We are installing a network of Contrologix PLCs. They are to help us diagnose the cause of a power failure.
We are intending to put these on a separate AC power supply from the power system that we are monitoring. This separate AC system has two power sources that are switched by a manual transfer switch.
The problem with this arrangement is that the separate AC system is not a make before break operation, so the power is interrupted for a split second during switching.
Without introducing maintenance-heavy UPS systems...is there anything out there that could keep these PLC's running through the switching procedure? perhaps even chassis mounted?
We are intending to put these on a separate AC power supply from the power system that we are monitoring. This separate AC system has two power sources that are switched by a manual transfer switch.
The problem with this arrangement is that the separate AC system is not a make before break operation, so the power is interrupted for a split second during switching.
Without introducing maintenance-heavy UPS systems...is there anything out there that could keep these PLC's running through the switching procedure? perhaps even chassis mounted?





RE: Uninterruptable power supply for Controllogix PLCs??
If the latter time period and DC, maybe capacitors?
RE: Uninterruptable power supply for Controllogix PLCs??
There are also several options for DC UPS systems to go behind 24VDC power supplies as well, they are nowhere near as complex as AC UPS systems since you already have the DC power supply. They still have batteries though, and batteries need to be replaced periodically.
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RE: Uninterruptable power supply for Controllogix PLCs??
Last system I retrofitted the AB UPS on was three ControlLogix PLC racks and two VersaView HMI's, they were feed from a non-critical ATS and transfer time was 25 seconds, to date no problems reported.
Hope that helps,
Mike L.
RE: Uninterruptable power supply for Controllogix PLCs??
I'm trying to find out the switching time. And its not just one switch. The plant has tried to create a low voltage power center source that can be relied upon in almost any scenario, by feeding it from alternate sources.
In talking to our IT guy he also indicated they've had lots of problems with small UPS units, particularly when the batteries go dead - the network goes dead. This doesn't sound like a very good design.
The voltage is 120VAC but we haven't purchased anything yet. We also have available 125VDC except there are issues with it as well, the 120VAC is considered more reliable.
RE: Uninterruptable power supply for Controllogix PLCs??
Is something like this possible?
Or perhaps bring in the two sources so that we could do a hot swap on the 120VAC. Is this a common practice?
As you can may be tell...I'm a novice about stuff like this.
RE: Uninterruptable power supply for Controllogix PLCs??
RE: Uninterruptable power supply for Controllogix PLCs??
RE: Uninterruptable power supply for Controllogix PLCs??
I'm running a system right now where we used the 24V DC ControlLogix supplies and ordinary A-B 1606 power supplies with Phoenix Contact Quint UPS units. We can run the controller and a couple of I/O racks for twenty minutes with the AC line down, which keeps our data acquisition live in the event of a power interruption.
If you have a manual transfer and there will be only a few hundred milliseconds interruption in the AC line, the QUINT Buffer modules might be just the solution, so you don't need a central on-line uninterruptible AC source.