UPS for remote PLC5 rack

[Seewald]

I am looking for a bullet proof UPS that can handle temps up to 60 deg C. This is a remote rack at a pumping station. When power is lost, we loose seal water for our slurry pumps.

We need some type of power supply that will keep the rack up for a few seconds so the data table gets updated and breaker status, amps, pressures, etc are updated.

We are not looking for control, just status. We have tried computer grade UPS in the past, but they did not last, and have caused rack faults of their own so we removed all of them.

This is a remote rack, no processor, just an ASB and a few cards. I am looking for something bulletproof and simple that can be used in extreme conditions.

 

[dmargineau]

I'd try the AB 1609 UPS product line.
http://ab.rockwellautomation.com/Power-Supplies/Uninterruptible-Power-Supplies
I believe they will go as high as 10KVA for 208/230V applications and up to 3KVA for 120V.

 

[cornbread]

We are pleased with our Liebert UPS, I think they are a division of Emmerson... just google Liebert UPS.

 

[rdrast]

Do you want to power just the rack? or the IO as well? And is it 120V IO or DC?

If just the rack, I'd use a 24VDC battery backup system and a 1771-P5 or P5E slot power supply.

 

[The Plc Kid]

I'd try the AB 1609 UPS product line.
http://ab.rockwellautomation.com/Power-Supplies/Uninterruptible-Power-Supplies
I believe they will go as high as 10KVA for 208/230V applications and up to 3KVA for 120V.

We have a few of those but most of them are line interactive units. Online units (Double Conversion)units seem to fair better on the factory floor. This is even greater issue if you have power quality issues low vlotage,sags,which are present in many plants a line interactive unit does not survive long as it switches in a lot.

 

[The Plc Kid]

I really wish AB would come out with a online version in the 1609-S format.

 

[Seewald]

I don't want to power any IO just the rack. Not going to do the 24V power supply either, that would make it an odd ball, all of our other racks use the 1771-P7 power supply.

I am thinking of trying the SOLA SDU 500.

Does any one have experience with capacitor based UPS? I think we use to have some that provided 250 VDC.

 

[daba]

I am looking for a bullet proof UPS that can handle temps up to 60 deg C. This is a remote rack at a pumping station. When power is lost, we loose seal water for our slurry pumps.

We need some type of power supply that will keep the rack up for a few seconds so the data table gets updated and breaker status, amps, pressures, etc are updated.

We are not looking for control, just status. We have tried computer grade UPS in the past, but they did not last, and have caused rack faults of their own so we removed all of them.

This is a remote rack, no processor, just an ASB and a few cards. I am looking for something bulletproof and simple that can be used in extreme conditions.

I think you need to look at a bigger picture,

You say you need to "capture" breaker status, amps, pressures, etc., at the point of power failure. Some questions...

What will that information be used for?
Will it be significantly different from the last I/O update ?
How will that data be used on restart?
Will reading the data some time after the power outage has occurred make the data meaningful?

I just don't know what you are going to do with this "data" you collect as the plant is falling apart due to power-loss...

I would have thought the last I/O update data would be guaranteed to be the most valid, and for breaker status, you can assume they will open on a power-fail, you don't need to read this.

my 2c

 

[Seewald]

I don't have full background on what happened but my best guess is operators racked out the wrong breaker. When the remote pump station tripped off, the remote PLC rack lost power and communications, the IO did not update, keeping the last values received in the data table on the processor. The DCS did not indicate any problems to the operators because pumps where still showing running. They probably got a rack fault alarm, but didn't do any thing because everything showed good. We want to keep the rack up long enough to show breakers open, etc., long enough for the data table to update over DH+ RIO. Looking at the historical trends, everthing just flatlined, no states changed.

We do not want to fault the processor on loss of the remote rack, they can switch to another seal water source.

Restarting pumps will not be a big deal once power is restored.


Is there a simple way to update the data table on PLC5 on loss of a remote rack?

 

[rdrast]

I only suggest 24VDC backups, as I've never had one of them fail (except for bad batteries, which they identify and alarm on). On the other hand, I've had just about every brand of AC UPS fail. Some people like the Sola units, and maybe they got better. I pulled a dozen of them out of one line, because not a single one functioned (brand new).

The closest to an indestructible AC UPS that I do use, is the Eaton Ferrups line, but they come with a hefty price tag.

 

[daba]

They probably got a rack fault alarm, but didn't do any thing because everything showed good.

So now you tell us that the whole of the control logic hasn't been designed to accommodate remote I/O failures - it just keeps on thinking the remote chassis is giving good data ? Ooops !!

Control code should not only look at input data, but should also check that the input data is still valid !

The information you need is in the PLC status file, and should have been used in the logic somewhere to determine that the processor has contact with the remote chassis.

Presumably when nothing disturbs the peace and quiet, you have a "good program". IMHO though, you have a BAD program when a remote chassis can disappear and the program doesn't do anything about it.