25 yr old PLC junk

[ptonsparky]

Good Golly Molly that battery is expensive! I realize I don’t get decent pricing for AB, but that turned out be $3200 a pound or better. I don’t think it weighs an ounce, including the box.

 

[RumRunner]

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.

This dated AB Model has their BIOS memory burned in. You usually don't mess with burned-in memory.
You don't boot beyond the kernel or you are too late in the booting sequence.

The BIOS chip is soldered in place in the motherboard that is separate from the main processor.
They are made independent of other chip makers.

There are only four popular BIOS makers in the industry they are:

American Megatrends Inc. (AMI)
Phoenix Technologies
ALi
Winbond

 

[zbang]

American Megatrends Inc. (AMI)
Phoenix Technologies
ALi
Winbond

And they're all awful in their own way. IIRC, at one time, the Phoenix x64 bios could only be built/packaged on a wondoze system with the cmd.exe "dos box"; some of the packager code would not run in cygwin so the build wasn't completely automatable (unless you wrote a new .bat file each run and got windoze to start a dos box with that).

I haven't seen ALi or Winbond, but I've heard stories.

 

[Jraef]

Good Golly Molly that battery is expensive! I realize I don’t get decent pricing for AB, but that turned out be $3200 a pound or better. I don’t think it weighs an ounce, including the box.

As a general rule, A-B supports obsolete equipment for a LOOONG time, longer than anyone else in the industry. But they DO like to "encourage" customers to upgrade by making it painful to keep using obsolete parts. That pain is the price they charge for the replacement parts once something is made obsolete. But in the case of batteries, A-B doesn't make batteries, they buy them and the people who sell them will sell them to you too, usually for much much less. You can get the Li-ion batteries for ML1500s for around $15 from lots of other sources besides an A-B distributor, and that thing is LONG out of warranty anyway, so it's not going to affect anything along those lines.

Side note; you can add an EEPROM memory card to the ML1500, it's a 1764-MM1 (or 1764-MM1RTC if you want the Real Time Clock too).

As to using non-volatile memory, there is a down side to that too. EEPROM memory has a finite number of write/erase cycles, usually about 100,000. EEPROM is significantly slower, so PLCs use RAM for execution of the program, the EEPROM is just used to store the last state of the RAM, or operational data. When power is removed / lost, the last state of the RAM memory is written to the EEPROM, then on power up it is read from the EEPROM and put back into RAM for action. If you power down once per day, that EEPROM will last almost 275 years.

But if you are constantly updating the EEPROM with state data so that you capture operating points and history, to where you have 1,000 writes/day, your EEPROM would only last around 4 months. So you have to manage how you store data to the EEPROM to assure it is there for you when you need it.

 

[RumRunner]

And they're all awful in their own way. IIRC, at one time, the Phoenix x64 bios could only be built/packaged on a wondoze system with the cmd.exe "dos box"; some of the packager code would not run in cygwin so the build wasn't completely automatable (unless you wrote a new .bat file each run and got windoze to start a dos box with that).

I haven't seen ALi or Winbond, but I've heard stories.

OK, wonderful sensationalist.
What are your alternatives?
If you have better units that will satisfy everyone—post them here.

I’ll put out a good word and perhaps use your ideas to work.
Resorting to old school modifying “command lines” like we do in DOS is going back twenty to thirty years.

I doubt new users would even know the different DOS systems.
It’s time to get real.

 

[zbang]

OK, wonderful sensationalist.
What are your alternatives?

I didn't say there were any, please reread my post- if you want an x86 BIOS, you're pretty much stuck with those four plus maybe SeaBios (and more likely down to phoenix/ami), and you're stuck with their build/package systems. There are also various bootloaders (e.g. uboot), but they're not generally suitable for general purpose systems.

I’ll put out a good word and perhaps use your ideas to work.
Resorting to old school modifying “command lines” like we do in DOS is going back twenty to thirty years.

Strangely enough, I was referring to maybe 12 years ago as "at one time". If you haven't worked on BIOS, or BMC code, or on bare-metal embedded systems, you may not have run into some of these issues. ("For this BMC and flash combo, you must use block formatter DSAHK which only runs in a windoze7 dos box on even-numbered Saturdays." "No, we won't give you the source code to fix it." I had almost that conversation with Phoenix, although it was 12ish years ago.)

I doubt new users would even know the different DOS systems.
It’s time to get real.

I've been doing that for 45 years.

 

[RumRunner]

I didn't say there were any, please reread my post- if you want an x86 BIOS, you're pretty much stuck with those four plus maybe SeaBios (and more likely down to phoenix/ami), and you're stuck with their build/package systems. There are also various bootloaders (e.g. uboot), but they're not generally suitable for general purpose systems.




Strangely enough, I was referring to maybe 12 years ago as "at one time". If you haven't worked on BIOS, or BMC code, or on bare-metal embedded systems, you may not have run into some of these issues. ("For this BMC and flash combo, you must use block formatter DSAHK which only runs in a windoze7 dos box on even-numbered Saturdays." "No, we won't give you the source code to fix it." I had almost that conversation with Phoenix, although it was 12ish years ago.)


I've been doing that for 45 years.

OK then. . . .so what happened to plug and play?
Teach those guys modern way of doing things.
And BTW:
I was one of the volunteers to teach school kids on how to use computers.
We offer them free services to private and public schools then.
Do you hold an IT Professional Certification? . . . .just curious.
It doesn't mean much but it will help travelling around the world being hired as a knowledge worker.
That's what keeping me busy in my retirement days.

 

[kwired]

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.

Was all three solutions an option on 25 year old equipment when it was new?

 

[zbang]

OK then. . . .so what happened to plug and play?

"Prug and Pray (on ISA)"? I remember when it was introduced; it barely worked at all, most people would disable it. (And EISA? Now there was a technical hairball.)

Do you hold an IT Professional Certification? . . . .just curious.

Never bothered; often I found myself fixing things that the "certified" people on-site couldn't (there are good ones and there are not-so-good ones). Come to think of it, you're the first person to ask about that in at least a few years.

 

[Jraef]

Was all three solutions an option on 25 year old equipment when it was new?

Not for the MicroLogix PLCs. Their place in the lineup was "cheap and small but can't do it all."

 

[tom baker]

When I maintained Micrologixs and SLCs, I would put the program on a USB drive and hang in the cabinet.

 

[petersonra]

When I maintained Micrologixs and SLCs, I would put the program on a USB drive and hang in the cabinet.

A lot of equipment that we put in car plants had a requirement for a box on the inside of the door. The box was for a three and a half inch floppy that they could store the program on.

 

[ptonsparky]

When I maintained Micrologixs and SLCs, I would put the program on a USB drive and hang in the cabinet.

That’s a good idea. I gave one to the manager/customer back when. He doesn’t remember at all.

I put the bug in their ear it’s time to update. The demands of the system have gotten considerably less over the last year and alternate products are readily available.

 

[Jraef]

When I maintained Micrologixs and SLCs, I would put the program on a USB drive and hang in the cabinet.

Oh, is THAT what those were? I thought they were free USB drives for transferring my pictures. Thanks!

Seriously though, good idea. I had to get something off of an old 5-1/4" floppy last month, took me 4 days to find the external floppy drive I had rescued from the recycle bin, then find a driver for it etc. etc. I put that data on a USB stick now, but I find myself wondering if, in another 10 or so years, I will be scrambling to find a USB port on something...

 

[zbang]

That's a long-standing problem, and not only finding a device to read the data (ZipDrive disks?), but software to understand the data. Twenty five years ago, Lotus AmiPro was a common word processor.... (I might still have some files from it.)

Digital archivists have to watch media deterioration, device availability, and whether the software to interpret the data will still run. You can still find companies that can transfer a U-Matic video tape or a 9-track computer tape, but interpreting those files from Interleaf Publishing or Atex? Might be a tough one.

Best you can do is high-quality storage devices, extra copies of the programs (and info about how to use them), and friendly physical storage. And periodically re-copying everything to a newer device.