Frequently checking backup batteries on HMI's is essential preventative maintenance protocol.

2 Things You Need to Do When Buying or Repairing an HMI (Human Machine Interface)

HMI repair

Maintaining an up-to-date copy of the software in your HMI can save your machine.


A Common Scenario When Purchasing a Machine: a conversation with a service technician from the field

Let me go over some of the common problems when purchasing a used machine. Yesterday, I was basically at a customers, they bought a machine, when they purchased the machine they thought it was in good, working condition, at least that’s what they were told.  Inside of that machine there are literally four or five computers and every one of those computers there are processors which have memory, software and a program(s). And there’s a battery that backs up that program.  And what I found, and I find it often, is a break in preventative maintenance – they’re not even checking these batteries. They’re not even replacing these batteries. They’re not doing anything with them, the former owner, nor does the new owner check.  So let’s say the customer buys the machine and they hook it up and they do other mechanical checks and they get it so that it’s mounted to the floor and all the hydraulic pumps hooked up. It’s beautiful!  It’s all beautiful!  They go to throw the switch, and presto – the thing doesn’t work!

So now what happened?  When the battery died the program was lost. The customer needed to have a way or needs to have somebody they can call or needs to have some way of backing up their software and their HMI (Human Machine Interface).  So, if the customer can’t do it themselves, they need to find somebody that can because when it’s go time this machine’s down, or when they just bought a machine – here there’s a thousand rungs of ladder logic that’s just gone.  Machine is virtually a boat anchor.  They should check that out up front when buying a machine.  They didn’t do that – and it makes the machine scrap



How reliable is the OEM on holding on to the original software?

No. You can’t rely on the OEM.  The machine builder who, let’s say, built the machine but in 10 different variations with the conveyor belt here or light bulb there… well that changes the whole ladder and just by having a door switch, it changes the whole machine. “Yeah, we got a copy of that, but oh, I forgot we added this buzzer, and the buzzer has to tell me when it went off…”  Maybe a new switch was added, or any alteration would change the software.  When they got a copy of that originally, things may have changed on the machine and they may not have the right software for your system any longer.  So, the customer, if they’re buying something, they need to make sure that the batteries are good and they got the program. If they’ve got something on their floor and they’re using it, they need to backup that software some way, somehow.  If there’s somebody around with a laptop, go copy the hard drives, at least they’ve got something.  Because when that thing goes down, when they throw the “on and off” switch or whatever it is, and that program isn’t there – its junk!  The machine is junk!

It’s very difficult for somebody like me to go into a customer and look them in the eyes and say, “I’m sorry, programs missing.  What are you going to do?”  When it comes to buying an HMI, do they have a way to copy their program and switch it over?  The HMI is its own computer.  The PLC is its own computer.  It’s when there could be four or five different computers in there; they’ve got to talk all together. What do they do with their program when you buy it from us? Some cases I could move. In some cases it’s lost. Some cases the machine builder can’t do anything about it, so I always have a backup, always back it up. However you can do it, make a copy, make a copy, and make a copy!!  Have a hard copy of it on a thumb drive. Have it on a CD rom.  Have it somewhere stored safely away.

And if you have someone internally, every time you make a change on your machine like that, put the days date and back it up.  Or, if they’re buying a machine, they should do some homework and say, well, who built this machine?  Or it’s a Fidel with Fanuc controls. OK, can I call Fidel and say, “hey, I got this machine’s serial number, blah blah blah, blah. I’m looking at purchasing. I’m not sure if the program is in it. Do you guys even have a program, what do I do with this HMI? When, I, you know, power it up and it says bad battery, do you have this program…?”

Frequently checking backup batteries on an HMI should be a part of preventative maintenance protocol.

Frequently checking backup batteries on an HMI should be a part of preventative maintenance protocol.


2 things you need to do when buying or repairing an HMI –

  • Check back-up batteries, change when needed
  • Back-up software before sending for repair or replacing


So, if you are buying and replacing an HMI you should always back the software up and then load it into the new one, or if you’re sending in for repair, you should back it up if you can before you even send it out, or if it’s one of those machines that runs 24/7, it never shuts off – check the battery. Generally, you could do it with power on, you need to do it with power-on, because you can’t shut it off or everything will be erased – and then there is a backup if the power does goes out.  And you always have to keep checking batteries.  Make it part of your preventative maintenance protocol.  Check the batteries!

Most batteries are accessible from the outside of the unit. But, there are some that you won’t know the battery is bad until it’s bad, until you need to use it, and it’s not there.  In some cases, when we are repairing an HMI,  we can move programs from one unit to another.

This type of maintenance neglect hits all sizes of companies; from your giant, international automotive parts manufacturer to the small machine shop down the street – it happens all the time.  OEM’s don’t save the programs themselves, some OEM’s are like a one-shot custom built machine so they program it on the spot but then 15-20 years later that guy doesn’t know what he did or doesn’t remember how they programmed it – or is out of business!  This is not really a one shoe fits all. It’s definitely common.  Also common, that some of these places will go in and make that one-time adjustment to your machine and you pay them a heavy fee and the minute they walk out the door, they don’t even know what they did.  So the next time when you call, maybe that brand of PLC or HMI is gone by the wayside and of course they upgraded. So now this company that you’d called originally, to have them do a tweak or whatever, they say, “well we don’t support that anymore, so you’re going to have to upgrade.” Some of those upgrades could be hundreds of thousands of dollars. You’re talking a lot of money when you start putting new PLC’s and the time to build a ladder, etc., where if they had a backup, reload it and you’re good to go.


Summary: Reasons why it is a good idea to back-up software on HMI’s

  • Your repair expert will not always be able to retain or retrieve your software.
  • Without a good backup it will be difficult to get original software from the machine builder.
  • Over time, some files may get corrupted causing equipment to malfunction; If the files are wiped clean and reloaded with proper software it could fix your machine issue without you having to send the unit in for repair.
  • It is easier to purchase backup units or replacements to prevent machine downtime.
  • If a mother board or control board on an HMI needs replacing, it is not guaranteed technicians can transfer your current applications.
  • With electronics, there is always the possibility of losing crucial information during repair. For example, memory batteries have to be unplugged in order to make repairs.
  • In some cases, information may be lost during an extended power down.


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