Program recovery?

[Joel Moore]

I have a feeling I already know the answer to this but I figured I should ask anyway.  Is there any way to recover a program from a PLC in the event you lose the source code?

[support]

As this is an OEM PLC most OEM users would rather not allow other people from "recovering" (or should we say reverse-engineering") their program. Hence TRiLOGI 5.xx does not have any upload function for you to recover the program from the PLC into the PC should you lose your source file. It is pertinent for OEM equipment manufacture to copy their source file into some backup devices or print out hard copy of the program for safe storage.

What about signing up for a gmail account and get 1GB free storage space? You can email a copy of your source file to be stored on Google earthquake-proof, hurricane-proof and possibly terrorist-proof facility and therefore there is no need to worry about losing the source file anymore

[Joel Moore]

Good point about the reverse engineering by the customer.

As it turns out we do have the correct source.  Someone (i.e. me) just forgot to update the version information contained within.

[evanh]

One of the features of the common PLC is it's abillity to be edited by any competent sparky in the field with no more than the generic editing software.  The end user of the equipment is not interested in building a copy, after all, recreating the logic sequences just from watching the machine is quite simple compared to copying the engineering of the machine.  What's far more important about PLC's is when the end user notices a way to fit the machine into their production line with just a small logic change and it's just a simple case of of adding/modifying a couple of rungs of the existing ladder.  Removing this ability destroys the very feature that makes the PLC distinctive.


Evan

[evanh]

Just to address the OEM point, most machinery is OEM built and plenty have simple PLC programs running in them.  Some use locked programs some don't.  Some are very large and complicated machines and no one tries to fiddle with them while others are simple and obvious how they work.

The ones that have a simple function are the sort that TriPLC is most suited to and are also the ones that are sandwiched in the middle of bigger equipment acting as glue or atleast that's what the management are expecting to happen.  Being able to tweak such a device is a desirable abillity.

It's also common for these to be a one-off contract job that is slapped together and the "official support" soon fades away.  The software is not stored anywhere nor documented properly, relying on the ladder diagram to be the documentation.  Being able to edit the PLC contents directly is a very common situation, often having to later makeup the labelling for the I/O also.


Evan