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Help learning PLC


michairman

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Hello everyone, for 20+ years I have been into computer repair and misc electrical repair.  I have started working for a company that Has many Unitronics PLCs and need to learn ladder logic and all i can on how to fix and program them.  The support from Unitronics has been awesome and in my opinion I would never look elsewhere for a PLC solution.  So what im hoping is if anyone has any ideas on how/where I can learn both the hardware and programming side it would be highly appreciated.  My first step is to write the simple code to set the password on an sd card so I can create images of or PLC's for backups.  It is pry a simple task but for someone who is new to this its over my head at this moment.  I have an extra v570 that I can use to play with as I learn so im hoping to be able to write the ladder put sd card in it set it then use that sd card to clone one plc then do it again with another sd card until I have backups of all plcs in our building.  Thank you for any Help or guidance your willing to share.

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  • MVP 2023
19 minutes ago, michairman said:

My first step is to write the simple code to set the password on an sd card so I can create images of or PLC's for backups.

This sounds like you misunderstand how the SD card password works. It's not part of the SD card - it's in the program you want backed up BEFORE it's downloaded to the PLC. If you have the .vlp files then you will be able to do the backups by adding the Set SD Password FB to each program and re-downloading to the PLCs. If not, then you won't be able to do the backup.

My best suggestion for learning is to watch the Unitronics training webinars and reviewing the example programs that came with your VisiLogic installation. After that, practice, starting with simple projects.

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Yes it does sound like I have a lot to learn.  I do have the file but what im afraid of is loosing all our offsets and misc k factors that are inside the units memory.  I had to replace one of our dry rooms v570 s and it took me 2 weeks to get them back and they are nothing compared to our Vacuum Kiln and other Units we have.  Is there a way to backup all the settings and o/s without a password?or sd card? 

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8 hours ago, michairman said:

As a newbie here can you tell me how to identify if the settings are being saved as registers?

That is a HUGE program. It would take hours to go through it in detail. You will need to identify the settings you're asking about.

As a general rule, any value entered from the HMI is either stored in a register (or Memory Bit) or a Data Table. Both will be retained as long as either 24v power is applied or the battery is good. Review the Help file regarding Operands to familiarize yourself with Unitronics PLC operational memory. If you have any concerns, then do as Gabriel Franco suggested above.

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As well as Gabriel's export suggestion, have a look at using Edit/Export Operands Descriptions which will give you a perhaps more easily interpreted Excel file.

For any data tables that might exist, View/Data Tables and then use Connection/Read Structure and Values from PLC.  Once the read is finished, go back to File, don't choose save, but choose whatever Export function suits you best, which will likely be Export to File as the default .upd.

All of this should ensure that you have everything that is currently in the plc.

cheers, Aus

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9 hours ago, Flex727 said:

This will NOT provide the values of those operands, however.

True.  I forgot to add that I combine the resultant text and excel files into one excel file, with some simple copy/paste.  The beauty of this is that you have the descriptions provided for the MIs etc as well as the values.

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Thank you to everyone that has given me input.  Yes this is a larger file but it needs cleaned up a lot as many features we dont use and after unitronics helped me out in it one day he pointed out the extra junk is just slowing us down.  I will try as you all have said and see what happens the benefit is i believe i can copy all the tables, operands, and such  then switch to our backup plc and reload if everything works and all sensors read correctly and the water meter measures right then It was a success.  Do you see an issue or something im missing?  Thanks again

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If everything is currently working, and you take copies of the program and all the other info mentioned here, and make a backup of those copies, you are in theory OK to go. 

Another thing to be aware of is that Visilogic at some stage might insist that you update the PLC's O/S, or update your program.  If you are currently communicating OK with the 570, don't upgrade Visilogic at present to a newer version.  Stay with the version that is working. Updating things will likely lead to all sorts of problems and if anything like the attached screenshot comes up, immediately back out very carefully from everything that has been presented.  The screenshot is derived from Connection/Communicaton & O/S/ 4th tab (Operating System) and then clicking check.  I did this on a system that I knew would want the O/S upgraded.  If your saved program itself is not compatible with the version you are using, you will get an alert box coming up when you first open it.   Again, don't allow the changes.  You'll have to find the older version that matches it.

516373090_OSupdatenono.gif.67bfd5f77907bfdacb6e97b0ff327bc0.gif

 

For information about this situation, read the post linked below and entire topic about Version Swapper, which is a facility that lets you work with various versions of Visilogic.  People who have worked with Vision controllers for years often find themselves in a situation where they have made a program using an older version, yet have the latest one on their systems.  So again working with a plc programmed years ago means the need to work with the version of Visilogic originally used.  Swapper lets this happen easily.  But in your case, I'd not be using any other version at all until you are very familiar with the entire way it all works. 

For now, to be doubly sure of everything, I'd load all your saved information from the running plc into your spare one, and swap them over which is not that hard to do.  If for some reason the process doesn't work, you have the original working plc you can put back in whilst you explore what went wrong.  But in theory it will all go ok.  If it works now, it will work again.  Plcs only work on what is provided to them, so if the exact same info is provided, and the plc's internal instruction set is exactly the same, it will do exactly the same thing. 

cheers, Aus

 

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1 hour ago, Ausman said:

Updating things will likely lead to all sorts of problems...

I totally agree with Ausman and NEVER upgrade the firmware of a working system. However, it's not likely to hose things, but my motto is the same as the engineer's creed: "if it ain't broke, don't fix it".

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Thank you you for all the help, This is likely a silly question, But when i open the new .vlp from the person that writes them currently.  I open it then import the tables and operands, then stop,  download and reset?  or do I do the download first,  then the operands and tables?  I have the new PLC(spare) in so im at the point of uploading to plc(download).  Thanks again for helping this is a great community of people here.

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1 hour ago, michairman said:

But when i open the new .vlp from the person that writes them currently.  I open it then import the tables and operands, then stop,  download and reset?  or do I do the download first,  then the operands and tables?

Download first.

This is not necessary, but with a new PLC I like to download a blank project first, do an Initialize & Reset, then download my project. This makes sure all memory in the PLC is cleared out.

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