Download Program Changes only without Modicon Quantum CPU Stop mode

[rohit2318]

Hello All,
we have one machine which having Modicon quantum PLC with CPU 140 CPU 651 50. I have plan to modify small changes in PLC program.
Is it possible to download or save changes online without put the CPU in STOP mode because to stop the machine will make huge production loss.
I am using Unity Pro13 software.

 

[Saffa]

If you're using Unity Pro V13 and you are actually running the Unity firmware on the quantum, then yes you can do online edits without needing to put the processor into stop, assuming you are just changing code.

You need to be connected to the PLC and online before making edits, unless in Project settings you have turned on the "virtually connected" mode, which let's you prepare online edits while offline. From memory, changing that setting requires a rebuild and download for some reason, but i might be wrong about that.

 

[Corsair]

Online editing

The Quantum with Unity allows you to do online changes during run IF you start out 'EQUAL'. This means the program in the project file and the one in the processor must match and not be 'DIFFERENT'.

When you connect to the processor if they are different you need to transfer the program from the CPU to the computer and then save the file to the drive on your computer. This can be done while the processor is running. Now the computer and the PLC will be EQUAL. From then on you can make changes and 'BUILD' the changes. A common mistake is to open up the project and make changes without connecting to the PLC first. If you build those changes the projects will not be equal. At that point you need to shut down the CPU and download - or do the upload transfer again and lose the changes that you just typed in.

A key difference between the Modicon architecture and Allen-Bradley is that register (data) contents can be saved separately from the program. If you do a total download with the processor halted all your setpoints and production totals are lost. They need to be uploaded and saved first before doing the program download. Then the registers need to be downloaded before the processor is started. I won't debate whether the Modicon or the AB architecture is 'better' - each has its advantages and disadvantages.

With most PLCs the term 'download' means from the computer to the PLC and 'upload' means from the PLC to the computer. This tends to confuse people with computer backgrounds. The current Modicon software uses the term 'transfer' specifying a direction in an attempt to avoid the confusion. Make very sure you are always aware of what direction things are going.

Changing instance data configuration in a DFB or processor configuration requires an offline rebuild and a total download.

All the best to you on your project.

 

[rohit2318]

Thanks Mr Corsair & Mr. Saffa, I got your point.
Thanks a lot.