Plant Shutdown

We are planning a complete plant shutdown to inspect our electrical distribution system (8 to 10 hours). My question is should anything be done to the controllers before shutting off the power? We are using SLC's and CLC's with battery backup only. Thanks in advance for any suggestions.

Check the dates of the last battery change.
I am not sure of the expected life of a battery.

Back everything up to PC. If you do that, you should be covered.

Rick's advice is correct. To carry it one step further. If the batteries are OK, they should carry you through the shutdown with no problems. Murphy's law being a factor in any situation, you need to protect yourself by maintaining backup copies of all programs. You should also make sure that your version of the programming software is compatible with all of the CPU models and that you can read the backup version from the storage medium.

When you're trying to restore the program in a critical piece of equipment, it's no time to find out that the floppy with the backup file has a bad sector.

And while you are down, And you are sure of your back-up disks,etc....Change out the batteries and tighten the connections in the PLC panels...it is supprising how relays clacking away all year will shake screws loose!

David

Point-1: (be damned sure to read Point-2!)
If your system is on a network with more than one PC (with the appropriate programming software), backup the PLC Program to as many PC's as you can. Then, copy at least one of the backups to a floppy disk (each to a separate floppy). Include the process name and date in the filename and give it a "file-type" of ".bup" (backup) or some such... something unique to help you recognize it as one of your process backups.

Don't use a refrigerator magnet to hold the floppy-disk on the side of your filing cabinet.

If necessary, you can restore your process from any one of those PC's or, in a pinch, from one of the floppies.

Point-2:
Of course, the whole exercise of making a backup is moot if this is a PLC from an OEM and you folks don't have the software to access the PLC. In that case, DON"T TOUCH THAT BATTERY!

You will simply have to acquire the software (PLC-specific) necessary to accomplish a backup and download (or is it upload?... how 'bout reload?).

If you are lucky, you have the software and an OEM-provided backup. If nothing else, contact the OEM for recommendations.

That brings to surface a question that was recently posted...
It asked about being able to simply backup a PLC, as in "Dump yer Brains" and then "Reload yer Brains"... in a really, bit-wise, generic fashion. Sounds like it ought to be able to happen... huh? Peter?

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I have always liked to have a floppy, a copy in at least one computer, and a hard copy.

My suggestion is that all the controllers be shut off prior to power down. Normally, I would expect each machine to have it's own main disconnect, or each area of the plant. I am getting more chicken with power spikes in my old age. I've seen some wierd stuph the last few years, especially in one local small town with it's own electrical power utility.

The largest plant that I ever worked in had regular total shutdowns, and didn't really have any many problems on power up, but I was never in there when it happened. My section had around 400 plcs, and the plant probably had 600 total. Many had a latching circuit on the power, similar to a MCR relay circuit, so they were automatically shut down.

I try to avoid anything that will cause me to have to go triubleshoot and repair. I would rather be creative, design, build new, than maintenance any time.

regards....casey

Terry Woods said:

That brings to surface a question that was recently posted...
It asked about being able to simply backup a PLC, as in "Dump yer Brains" and then "Reload yer Brains"... in a really, bit-wise, generic fashion. Sounds like it ought to be able to happen... huh? Peter?

Click to expand...

A-D has a standalone utility that does EXACTLY that, called DNLoader. No programming software required...

Oh, and it's FREE by the way...

Regarding backups, I would recommend NOT using a floppy for backup. Use a CD or some other reliable storage media. Floppys (floppies?) seem to be VERY unreliable nowadays...

beerchug

-Eric

CD's - GOOD suggestion, specially rewritable.

Unfortunately, some of us still have antique equipment. I see a few factories still using laptops with a 386 processor. Perhaps the real reason LogicMaster is DOS based.

Haven't seen one, but heard of laptops and tower cpu's that don't have a floppy drive.

Speaking of antique, I was in one plant that the most modern piece of equipment is their hand held programmer. Most programs are hand wrote on graph paper. When I was in there in 99, I printed out hard copys from my laptop, left floppies, and LogicMaster. Their maintenance people couldn't figure how to load the software, so progess died fast.

Terry Woods - Point 2 is excellant. On occaision I run across a machine someone has put an off brand controller in it to make the machine quasi-proprietory. And with no backup program, that battery function can be mighty important. Makes for some costly factory field service calls, just to reload the program.

regards........casey

BENNY said:

We are planning a complete plant shutdown to inspect our electrical distribution system (8 to 10 hours).

Click to expand...

I was just curious...what is the scope of the Electrical System Inspection you are going to perform??

I know I can burn hours just testing to see if terminal screws are tight. What all do you have planned right now?

IR inspection of CB's?
Dust and dirt blow out?
Schematic audit?
Labeling?
GFI testing?
Reseat Relays?
Audit MOV placement?
Fuses reseated?
Tug each and every wire for connection?

It is easy for these PM's to be turned into a pencil whip.

I'd like to invite the community to throw out their typical PM items...

One more point, learned by experience.

Shut down your plant in an orderly manner, then isolate each machine.
Especially make sure that your sensitive electronic devices such as PLCs, PCs and networking equipment. This will save the equipment from suffering from transient damage when you switch off and on your main distribution system.

Doug

Re: Re: Plant Shutdown

Hester said:

Dust and dirt blow out?

Click to expand...

Consider changing that to dust and dirt VACUUM out, Hester. Using compressed air to 'clean' usually just winds up embedding the **** even deeper!...

IMO, electrical enclosures should never get dirty inside. Most get dirty because the cabinet door is open more often than it's closed. IOW, a dirty enclosure interior is usually a sign that someone needs to go in there W-A-Y too often. The question is, why?...

Another cause of a dirty enclosure is inept mechanics that always feel the need to open the cabinet, 'cause the problem is ALWAYS something electrical (even though it rarely is)...

Not to brag (OK, I will)...

I recently made a minor program change to a piece of equipment we installed back in '98. The machine has been running 24/7 since installation, yet when I opened the cabinet, it was spotless, and still had a trace of that 'new enclosure' scent. The customer said they never needed to open it, because the machine had been running fine for all these years. Here's a picture I took while I was there.

[attachment]

Wish I could keep my CAR that clean...

beerchug

-Eric

Nice Install!!!

I work in the Paper Converting Industry sector, and Paper dust is everywhere. I found that blowing out with CDA is quicker, and removes more debris faster.

You have a point about the enclosure being clean. Nothing should get into the enclosure, but Ronald McDonald has been here, and a lot of the enclosures have unplugged holes I have not been able to seal up yet. Not to mention the enclosures are usually fan cooled and suck dust into any available crack. Consider a Cement Factory...

Sometimes CDA is the lesser of evils on a PM. You are right about vacuuming be the first choice Pick your poison.

Hester said:

Not to mention the enclosures are usually fan cooled and suck dust into any available crack.

Click to expand...

I always have the fan blowing air INTO the enclosure, rather than sucking it OUT. A little positive pressure prevents sucking dust "into every available crack"... :nodi:

Of course this become a mute point when some bozo removes the filter altogether, "because it was dirty"...

Also consider if the application really needs a fan in the first place. Alternatively, an internal fan can be used to provide air circulation. The surface area of the enclosure often provides more than enough heat dissipation. Read the 'Thermal Management' section in the back of any Hoffman 'Specifier's Guide', or download the PDF version HERE.

beerchug

-Eric

Enclosure Cooling

Eric Nelson said:

I always have the fan blowing air INTO the enclosure, rather than sucking it OUT. A little positive pressure prevents sucking dust "into every available crack"

Click to expand...

Well consider this: Most "Filters" allow plenty of particles over 100 u to blow straight into your enclosure. For those of you unfamiliar with microns, 25 u equals .001".

Power Supplies, due to ionization are magnets for dust, and guess where these 100 u+ particles wind up? On every ionized surface in your cabinet.

My first choice is always positive air pressure, but I always prefer Positive Air Pressure enclosure dessication to fans. Fans burn out, fans don't get replaced, fans don't provide reliable positive air pressure.
I prefer to route in 5 psi of CDA (Compressed Dry Air) monitored by a SCCM Flow meter, and create a positive pressure that way. Ideally .25 - .4 " H20 of positive pressure.
Does this air have a charge? Yes or No? Yes, but in the lesser of evils department, I prefer air over fans.

With regards to heat dissipation:
Automation Direct DL06 units are gauranteed to Operate up to 138 F. Well that is still pretty dang warm. A lot of my heat sinked 7815's run upwards of 150 F (which I don't like). Anyway - lots of heat dissipated.
My rule of thumb is try to keep the cabinet as close to ambient temperature as possible. It is repeated heating and cooling stress which destroys solid state devices in the long run, all other things being "Normal".

Just for laughs try using these equations and guides to determine what Heat Load your cabinet is generating, or for BTU/hr heat dissipation of your cabinet:
http://www.exair.com/cabinetcooler/cc_page.htm

Check out Exair Vortex Cabinet Coolers:
http://www.exair.com/vortextube/vt_page.htm

If you have a heat problem in a really dirty enviroment, (and no compressed air available) try peltier thermoelectric heat exchanger/pump. We did this at a foundry, and a few months later one of our guys found a six pack in the soft starter cabnet.

This isnt the one we used but you'll get the idea.

http://www.allelectronics.com/cgi-bin/category.cgi?category=450&item=PJT-4&type=store


Addemdem No. 1
Here it is!! http://www.melcor.com/maa280t.html