Honest Question: Do modern CNC machines still need battery storage for settings?

[SirRage]

It has confused the hell out of me why CNC machines, out of all machines, need battery storage. Computers have had non-volatile flash memory since the 80's and it's cheap enough if you just have to store a few setup values.

The shop next to me had the battery in their early 2000 something die and had to have a tech come over and reinstall parameters. That just blows my mind. I think it had a Fanuc controller in it.

So it got me thinking, do modern machines use batteries for storing system parameters as well?

 

[SeymourDumore]

Don't know about the Next-gen Haas control, but all the recent Fanucs do.
Why? When there is also a hard drive in most of them? I don't friggin' know!

 

[???]

Machine tools are vastly more expensive than your average PC and the cost of going down can be huge so probably makes sense to have some extra safety built in. Machine tool builders are also super conservative, my mid 2000s CNC lathe still has a floppy drive.

 

[Vancbiker]

When you look at the design lifespan for a Fanuc CNC compared to a generic “computer” by which I presumed you meant PC, you might recognize the manufacturer’s desire to use time proven and trusted architecture. The CNC will likely still be in service 30 or more years of age. It must still be safe and reliable. Can that be said for the majority of PCs?

Letting a battery go dead is just plain lazy, sloppy operation. Not having a current backup is stupid lazy behavior.

 

[Donkey Hotey]

It has confused the hell out of me why CNC machines, out of all machines, need battery storage. Computers have had non-volatile flash memory since the 80's and it's cheap enough if you just have to store a few setup values.

Actually, no they don't. Personal computers have the same exact problem. We don't normally keep personal computers long enough for the onboard battery to die. Just swapped the BIOS battery on a friend's PC in his Omax waterjet. I think it's an HP. I just looked at the HP workstation I'm typing this from. Yep, backup battery right by the RAM.

And FWIW: my old Garmin GPS III units that I used to use also have internal backup batteries that die after enough years. They scramble all their settings and defaults back to nothing every time I shut them off. It's not worth taking them apart to solder in replacement batteries.

 

[EmGo]

When you look at the design lifespan for a Fanuc CNC compared to a generic “computer” by which I presumed you meant PC, you might recognize the manufacturer’s desire to use time proven and trusted architecture. The CNC will likely still be in service 30 or more years of age. It must still be safe and reliable. Can that be said for the majority of PCs?

Bah. It's plain old laziness. The eprom was developed in 1971. The technology is proven and has been for fifty years. Deckel even used them for executive program storage. It's flatout stupid that controls still need batteries.

Letting a battery go dead is just plain lazy, sloppy operation. Not having a current backup is stupid lazy behavior.

Not having a backup (on tape !) is inadvisable but it happens, especially when you buy a used machine. But the battery thing these days is crap. Control builders kind of suck.

 

[SeymourDumore]

When you look at the design lifespan for a Fanuc CNC compared to a generic “computer” by which I presumed you meant PC, you might recognize the manufacturer’s desire to use time proven and trusted architecture.

Vanc, you KNOW that answer is an indefensible utter bullshit with today's technology right?
The architecture is NOT!!! the obstacle for implementing a system where battery dependent backup is the only way to salvage the world.
You KNOW it!

Letting a battery go dead is just plain lazy, sloppy operation. Not having a current backup is stupid lazy behavior.

First, not accurately monitoring a battery condition by the very control that absolutely depends on it IS a lazy, sloppy and inexcusable design!
Mitsubishi MSX-850, and Fanuc Oi-TC control Does not!!! adequately monitor the status of the batteries!

Second, you cannot back up the positional parameters with absolute encoders.
You just cannot.
Period.
The END!

I don't know if you ever installed brand new batteries that were defective from the box.
I have!
Twice!
Fucking thing cost me over $2K!
Once I've replaced batteries that were 5 years expired. Radio Shack sold them as new, I did not check the expiration date, put them in a Mori NL.
It died 7 months later.
Control parameters remained intact, but the GPS location sensor was not.
After getting the machine re-authorized, I found out that all the absolute encoder data was lost as well, and that took a service guy to re establish everything
on a 2 spindle Y axis machine, mostly because the manual fucking SUCKS in how it explains the procedure!
Then, the second time, the battery I purchased and checked with a VM before installing in a machine in the morning, ran through the day without warning.
Then, when I powered it up again the next morning I got the dreaded absolute encoder parameter lost message, only to find that one of the two 3V batteries now measure .2V!

So no, I do not buy the bullshit that "proven technology" is the reason behind the reliance behind battery backed up systems built today!

 

[usolutions]

Let me chime in on that last statement. Yes, controls are utter garbage at keeping tabs on batteries. I got older OTc brained lathe. When it arrived, everything was fine, no warnings no errors no alarms, but 2 days later full stack of servo and encoder errors. It was enough low voltage to encoders get amneesia, but not enough to get preventive error. Thank god it was not parameter batteries.

 

[SirRage]

This sounds like an engineering nightmare. The absolute encoders on my AcuRite DRO for my manual mill (I'm too cheap to own a CNC yet) for example lose the reference when the power is disconnected. But after about 3" of travel the encoder has read enough of the data to reestablish its location. You would think something that costs 50-100x more would be able to do this.

Rotary encoder would be able to establish its location pretty quickly, but there is no reason why the controller could not log these values in RAM and later on a shutdown, or standby, copy them over to EPROM or SSD.

Worst case scenario put limit switches in and home itself like a dumb stepper motor machine.

It just feels like a lot of bad engineering decisions went into making these types of machines. I'm guessing there were valid reasons for these tradeoffs, I just don't see them.

 

[Vancbiker]

@Seymore; No need to shout at me, just expressing my thoughts.

As far as battery stuff goes, the last 18 years of my working life was at a company with near 100 CNC machines of all types. Part of my job was managing the maintenance department. In those 18 years I can absolutely say we never had a machine lose parameter or position data due to dead batteries. It was just a part of our preventive maintenance program to change batteries annually. Everyone in the maintenance had Maglights using 3-4 D cells and never a worry about having to buy batteries. Never ran into a defective battery either though that certainly could happen.

I have personally never relied on looking for an error warning or indicator about battery life.

Now in retirement, my Makino with Fanuc 0MB gets an annual battery change. Cheap and easy as it's just 3 D cells. My Mori with Mitsu gets new batteries every 4 years despite the claim of a 10 year lifespan. It uses 6 AA lithium primary ceIls so the cost is about $70 to change them. Hence my reluctance to change more frequently. One could install AA battery holders and use lithium Energizers or similar at lower cost. So far, I have just continued with the solder tab style and just solder on the pigtails for the control and solder 4 of them to the PCB that is used to back up the encoders.

I do an annual data backup of both machines at the first of each year. It's an easy thing to remember. One copy stored on the shop PC. Another copy on a thumb drive at my house

These things, IMHO, are no less important than keeping the oil full and greasing when needed. Just part of the ownership and use of CNC machinery

 

[SeymourDumore]

@Seymore; No need to shout at me, just expressing my thoughts.

Was not intended as a shout, rather emphasis.
If a red highlight is better, please, by all means let me know.

Now in retirement, my Makino with Fanuc 0MB gets an annual battery change.
My Mori with Mitsu gets new batteries every 4 years despite the claim of a 10 year lifespan. One could install AA battery holders and use lithium Energizers or similar at lower cost.

And that is the point!
Why???

I use a flip phone, a tablet and occasionally a laptop.
Each and every single friggin' one tells me the status of the battery, down to the last goddamned percentage!
When they're low, they get plugged in.
If they need frequent plugging in, they get a new battery.
All of those are worth maybe $500.

Is it really that difficult to ask a control manufacturer to demand that their garbage @10X the cost do the same?
Should I be responsible to not only make sure the battery is replaced annually or every 4 years, but to also take daily voltage checks on each and every one just so I don't get fucked?

 

[???]

Dude calm down Sinha will report you

 

[drcoelho]

Brother Speedios require qty(3) AA batteries to maintain the volatile memory. And yes, if you let them go dead you lose your machine settings. I've now done this twice...very annoying, one feature I wish they would fix. For folks that run their machine daily, this might not be a problem, but for me, with months of non-use if I'm not diligent about it, I lose the settings (machine calibration).

 

[cngbrick]

Going back to the reliability argument, flash RAM technologies have a limited number of rewrite cycles, static RAM (SRAM) does not have the same restrictions but requires a battery to maintain its state.

Manufacturers don't know with certainty what chips will still be in production 15 or 20 years down the road if these die from excessive rewrites. Batteries however are much easier to adapt than trying to find a replacement for an obsolete memory chip that is soldered to a circuit board.

With respect to battery monitoring -- it's much harder to predict the failure point of a long lived battery than one that cycles continually from charged to empty over the course of a day. The algorithms also depend on the technology and even to a certain extent to the implementation of a specific manufacturer of battery. Again, the control manufacturer can't predict what battery chemistry and discharge profile will be available 10 years down the road which would render their charge monitoring algorithm obsolete.

 

[Donkey Hotey]

Haas gives a low battery alarm when it drops below a threshold. I finally gave up waiting for it after 19 years of procrastinating and replaced them. They measured 3.1V in circuit, before I removed them. That was last year and the old batteries still measure 3.1V. I hope the new ones are nearly as good. I know other (later) Haas machines I had ate those batteries in a few years.

 

[chip_maker]

Vanc, you KNOW that answer is an indefensible utter bullshit with today's technology right?
The architecture is NOT!!! the obstacle for implementing a system where battery dependent backup is the only way to salvage the world.
You KNOW it!



First, not accurately monitoring a battery condition by the very control that absolutely depends on it IS a lazy, sloppy and inexcusable design!
Mitsubishi MSX-850, and Fanuc Oi-TC control Does not!!! adequately monitor the status of the batteries!

Second, you cannot back up the positional parameters with absolute encoders.
You just cannot.
Period.
The END!

I don't know if you ever installed brand new batteries that were defective from the box.
I have!
Twice!
Fucking thing cost me over $2K!
Once I've replaced batteries that were 5 years expired. Radio Shack sold them as new, I did not check the expiration date, put them in a Mori NL.
It died 7 months later.
Control parameters remained intact, but the GPS location sensor was not.
After getting the machine re-authorized, I found out that all the absolute encoder data was lost as well, and that took a service guy to re establish everything
on a 2 spindle Y axis machine, mostly because the manual fucking SUCKS in how it explains the procedure!
Then, the second time, the battery I purchased and checked with a VM before installing in a machine in the morning, ran through the day without warning.
Then, when I powered it up again the next morning I got the dreaded absolute encoder parameter lost message, only to find that one of the two 3V batteries now measure .2V!

So no, I do not buy the bullshit that "proven technology" is the reason behind the reliance behind battery backed up systems built today!

My 2 O&H lathes with 18t's will give me a low battery alarm. My Doosan does not!

After a couple dead batteries and the associated bs that comes with that, I purchased a kit from these guys:

corednc

Life with the Doosan is much better now!

 

[gustafson]

the computer I am typing on is from 2011
I thinks its bios battery is dead since it won't keep time when powered off.
When CNC machines had 1000 lines of code and 100 parameters NBD.
Now, it is silly

 

[dandrummerman21]

Time to set up CNC machines with RAID5 I guess.

 

[Pete Deal]

Going back to the reliability argument, flash RAM technologies have a limited number of rewrite cycles, static RAM (SRAM) does not have the same restrictions but requires a battery to maintain its state.

Manufacturers don't know with certainty what chips will still be in production 15 or 20 years down the road if these die from excessive rewrites. Batteries however are much easier to adapt than trying to find a replacement for an obsolete memory chip that is soldered to a circuit board.

This I think is it^^^

I’ve done some embedded design at various times in my life. In one case I was writing the code to save configuration to nonvolatile memory. The way I implemented it wore the chip out very quickly. Had to change the firmware to prevent it. But for applications where lots of read/writes are necessary and need to be static, nonvolatile memory is a poor choice.

 

[empower]

Machine tools are vastly more expensive than your average PC and the cost of going down can be huge so probably makes sense to have some extra safety built in. Machine tool builders are also super conservative, my mid 2000s CNC lathe still has a floppy drive.

but its not extra safety... because if the batteries die, your machine is a paperweight.