25 yr old PLC junk

[ptonsparky]

Put in an AB 1500 close to 25 years ago. Not sure exactly when. Last time I have a back up of the program is 2011. Today it developed a fault code. Once I got online and cleared the fault there was no program loaded. Did I screw up? Wouldn't doubt it a bit. Took me awhile but loaded up the old and things are working again. Lo and behold I find out there is a battery in that thing. Life expectancy of 7-8 years depending on conditions and temperature. Ambient has ranged from -30 to +106 for 25 years. Piece of junk.

There is a question in there. What would I have had to do to erase the program? Did the power outage and no battery doom it?



eta: I was being sarcastic as far as 'Junk'

 

[petersonra]

We get calls pretty regularly from people who have PLCs that have died for various reasons and have no backup at all.

Likely at one time they had a backup but the guy who knew where it was kept has retired and died.

I had one guy who had this problem, dead battery during a power failure event. Backup was on 5.25 inch floppies. Fortunately at the time we actually had a computer with a 5.25 floppy that still functioned.

 

[tom baker]

Before I retired I kept a spread sheet for 39 locations with some 125 batteries, make, AH, replacement date...most were sealed lead acid, replaced on a 4 year cycle. I had a lot of AB plcs, those batteries were 5 year replacements. And each device had a label with battery install date. I knew a tech at a WWTP that didnt change batteries in UPSs, the UPS would die in an outage, sewage overflow...
I liked the ML1500, great little PLC.

 

[zbang]

And each device had a label with battery install date

IMNSHO, any backup battery that isn't date-marked is assumed to be EOL and should be replaced. Do that enough times and people might start marking them.

 

[paulengr]

Moore Industries used to sell “cable concentrator”. Basically Modbus cards that you used in pairs so you have an input card at one end and an output card at the other. Unlike Modbus it was peer to peer with no master, PLC, etc. very simple.

Except they used “zero RAM” chips that were ordinary static ram chips with a small coil cell strapped to the top. At about 10 years the cards would start acting up, losing memory, channels “going bad”, freezing up, etc. Sent out for rebuild as per boss. Usually came back and still has problems. When I took apart the zero rams and replaced the coin cells 90% of the time all the issues went away. Of course the battery was hidden and not easy to replace but nothing in maintenance is ever easy.

 

[cpickett]

Did the power outage and no battery doom it?

Yep, the Micrologix PLCs have batteries, as well as SLC, older 1769 CompactLogix, and older 1756 ControLogix. The battery keeps the program in memory on power loss. You can store the program into a memory module that it can load on boot up, but all the setpoints, etc will be loaded from what's stored, not from what was running, so those are a so-so solution. There's a battery light that will show when it needs replaced, but of course it's another maintenance item that usually gets ignored.

 

[ptonsparky]

Yep, the Micrologix PLCs have batteries, as well as SLC, older 1769 CompactLogix, and older 1756 ControLogix. The battery keeps the program in memory on power loss. You can store the program into a memory module that it can load on boot up, but all the setpoints, etc will be loaded from what's stored, not from what was running, so those are a so-so solution. There's a battery light that will show when it needs replaced, but of course it's another maintenance item that usually gets ignored.

I may have known there was battery back then but certainly forgot about it. Makes me wonder about another system I installed a few years later and haven’t seen since.

 

[hbiss]

What would I have had to do to erase the program? Did the power outage and no battery doom it?

Exactly. The battery is there to maintain the programming during a power outage.

-Hal

 

[GeorgeB]

I worked for a company in the early 1980s who had already been bit by EOL PLCs. We were required to use only PLCs with (permanently) included programmers. ISTR that Omron P0R was the only unit we found that met that requirement.

As an old-time 8080/Z80 assembly programmer, the boolean scheme worked fine. It was difficult for some, however.

We printed and laminated the program inside the cabinet exactly as panel schedules are done. When the battery died, there was a solution.

 

[petersonra]

I worked for a company in the early 1980s who had already been bit by EOL PLCs. We were required to use only PLCs with (permanently) included programmers. ISTR that Omron P0R was the only unit we found that met that requirement.

As an old-time 8080/Z80 assembly programmer, the boolean scheme worked fine. It was difficult for some, however.

We printed and laminated the program inside the cabinet exactly as panel schedules are done. When the battery died, there was a solution.

Not a bad solution for really simple stuff but does nothing for PLCs with 1000s of rungs of code. There is just no substitute for a system of backups and updating of old hardware as needed. The problem is that usually there is someone who does it that retires and the guys that take over don't even know he was doing it.

 

[MD Automation]

Our company here in MD is a bit of an odd duck in that we have never really worked inside the AB universe. It would be unusual for us to ever worry about losing a program from a Mains / battery problem. Our PLC experience involves companies like Lenze / Beckhoff / B&R – so a lot of European manufacturers (and a whole bunch of Germany vs Austria jokes). All of them hold programs in some kind of non-volatile memory. For example, none of the basic Lenze PLCs or Servo Drives we’ve used have any battery at all.

I will not get into the pros/ cons of avoiding the AB world – but it is unusual here in the USA, and every so often we have to put together a small pitch to potential customers as to why we are proposing a system that does NOT utilize AB components and controls.

There is just no substitute for a system of backups and updating of old hardware as needed. The problem is that usually there is someone who does it that retires and the guys that take over don't even know he was doing it.

100% agree! Our programs are always backed up in multiple places, with most of the code typically in some kind of repository for tracking changes (we like GitHub lately). At this point in my career, it would seem I am pretty close to being one of "those guys" that are the only ones who can still work on some old systems.

Some of our older deployed machines are already running into EOL problems – but that’s a whole other kettle of fish.

 

[cpickett]

Our company here in MD is a bit of an odd duck in that we have never really worked inside the AB universe. It would be unusual for us to ever worry about losing a program from a Mains / battery problem.

All of the current available CompactLogix and ControLogix processors retain their programs in nonvolatile memory, no more batteries. MicroLogix 1400s still have batteries, but they are somewhat on the way out, although we still use them fairly frequently. And since version 24 (I think), we finally get tag descriptions and rung comments stored in the PLC, woohoo!

We are an AB RSI (recognized systems integrator) so I am a bit biased, but the thing I do give Rockwell is that their products are supported for a loooong time. We have customers running PLC 5 systems that we can still support, and the software is still available and runs on modern computers.

 

[MD Automation]

All of the current available CompactLogix and ControLogix processors retain their programs in nonvolatile memory, no more batteries.

Good to know - and I'm not surprised at all. Just honestly clueless about your AB world.

We are an AB RSI (recognized systems integrator) so I am a bit biased, but the thing I do give Rockwell is that their products are supported for a loooong time. We have customers running PLC 5 systems that we can still support, and the software is still available and runs on modern computers.

Understood about your bias! And the ability to support crazy old systems is an absolute huge plus. Most of the contracts on larger machines we were involved with stipulated that vendors will support and manufacture spare(s) for 10 years. Long ago, when I was young, I thought that was an absurdly long time. Now that I am almost 200 years old, 10 years ain't so long

 

[Hv&Lv]

The round garage door batteries dying in the relays have bit me a couple of times. As Tom mentioned, we change them on a schedule now.

 

[paulengr]

Yep, the Micrologix PLCs have batteries, as well as SLC, older 1769 CompactLogix, and older 1756 ControLogix. The battery keeps the program in memory on power loss. You can store the program into a memory module that it can load on boot up, but all the setpoints, etc will be loaded from what's stored, not from what was running, so those are a so-so solution. There's a battery light that will show when it needs replaced, but of course it's another maintenance item that usually gets ignored.

The battery light is also highly unreliable. False negatives and positives.


Sent from my iPhone using Tapatalk

 

[paulengr]

AB does have a three solutions for backups. The first as mentioned is memory cards. Holds the program and SOME settings. Quick way to replace hardware. The second is that AB sells a software system you install on a server. It automatically periodically downloads the current program and data and keeps copies of different versions. Junior tech on 3rd shift scrambled the program? Just restore from backup and you’re back up in 5 minutes. Lost a processor? Replace and the server will restore the program. Not bad if you have a lot of networked processors and money to spend. Cheaper than keeping track. Third option is if you have an HMI install the programming software on it in the background.

Fourth option...many PLCs have free or cheap software. At over $6,000 per license plus a 20% annual maintenance fee just to be able to call tech support most systems are cheaper and just as good for the software as the software alone. A Toyo PLC with identical capabilities to the Micrologix line is less than the cost of one Micrologix card. As far as reliability I’ve seen them in quarries and recycling plants sucking dust, moisture, and dirt from busted conduits, doors, and rusted out fittings for decades and still functioning. Same as PLC 5, SLC, Micrologix. Well everything but the battery. Compact/Controllogix will never survive it.

 

[RumRunner]

Put in an AB 1500 close to 25 years ago. Not sure exactly when. Last time I have a back up of the program is 2011. Today it developed a fault code. Once I got online and cleared the fault there was no program loaded. Did I screw up? Wouldn't doubt it a bit. Took me awhile but loaded up the old and things are working again. Lo and behold I find out there is a battery in that thing. Life expectancy of 7-8 years depending on conditions and temperature. Ambient has ranged from -30 to +106 for 25 years. Piece of junk.

There is a question in there. What would I have had to do to erase the program? Did the power outage and no battery doom it?
eta: I was being sarcastic as far as 'Junk'

PLC is no different from a PC-- setting on your desk. One big difference is the PLC does repetitive instructions as opposed to PC.
It has its own processor and memory.

As with all computers big and small—they use CMOS Technology.
With this technology, a small lithium or Ni-Cad battery is installed that can supply power to keep data for years. Usually will last about 10 years. It will keep its memory when you turn off your PC or PLC.

This is the battery-- the size of a quarter hidden away in the motherboard.
The BIOS/ (Basic Input /Output System) and CMOS (Complementary Metal-Oxide Semi-conductor) are the very first instruction to be executed when you first tell the BOOTLOADER to do some work.
Computers don’t know what they are until you tell them (through human interaction) what they are-- unlike a bread toaster that will toast your bread when you plug it in.

BIOS/CMOS don’t need a lot of power to keep the memory.

They can get corrupted from losing power, lightning strike, virus and struggling from an old marginally supplying power from an old battery.
One way to tell that the battery is dying is: the date and some peripherals are not recognized on the setup page.
You can restore the CMOS by reloading it called flashing. Just make sure you make the entry correctly to match what you have in your PLC or PC.
Failed entry will show A BIOS APPLICATION ERROR-- 501 MESSAGE. (Microsoft Technology)
Other platforms use different nomenclature.

You can also keep a copy of your BIOS in a USB stick.
Though your 1500 MicroLogix PLC System is no longer in production --you maybe able to recover the BIOS through AB--the PLC manufacturer.

 

[ptonsparky]

I really liked working AB ML line. I understood the software and logic. The HMI they had a the time was terrible to work with. Once others came along that were more in my line of needs, I changed.

 

[petersonra]

I really liked working AB ML line. I understood the software and logic. The HMI they had a the time was terrible to work with. Once others came along that were more in my line of needs, I changed.

The micrologix line is pretty much gone. They were some real oddballs. One of them only existed so there would be a ML PLC that serviced devicenet. It used 1769 I/O cards from the compactlogix PLCs.

Of the bunch I never liked any of them except the 1100 and 1400 units. Relatively inexpensive and came with ethernet.

Maybe I am just used to them but the Panelviews HMIs have always been pretty straightforward to me. the PV800 is dirt cheap and works well enough, especially with the ML family.

 

[zbang]

You can restore the CMOS by reloading it called flashing

The bios program is usually held in flash memory (used to be PROMs), and if that's bad, it just gone (and if you can't run the bios or OS , you can't reflash). Only the settings are held in NVRAM, and there's usually a "reset-defaults" option to clean up any corruption.