S7-300 backup 1

[cokeguy]

We wish to backup an S7-300 PLC, but we have no experience with Simatic controllers (99% of our equipment is A-B, we have all the software for them, but none from Siemens).

Is there some sort of simple utility that lets you download/upload programs from an S7-300, or do we need to buy the whole programming software? We would like to try and do it ourselves before calling in a Siemens integrator.

Just for information, the CPU has a female DB9 connector, there are also a couple of Simatic HMIs with serial interfaces connected somewhere (I imagine that to a module, since the CPU has nothing connected to its serial(?) DB9 port)

Thanks for any comments or weblinks. By the way, the machine runs 24/7, so any procedure/upload should ideally be done without stopping the machine.

 

[jraef]

If you have a machine that needs to run 24/7 and you are concerned about even the few minutes it would take to download the program, I would think you would WANT to own a registered copy of the software!

As far as I know there is no less expensive alternative, and the PLC will not allow download while running. You can call Siemens Technical Services to set you up with this (or just do it for you) if you don't feel like hiring an integrator by the hour.

http://www2.sea.siemens.com/Support/SoftwareManagement.htm

 

[cokeguy]

Thanks jraef, you mean we cannot upload the program from the PLC while it is running?

The machine is not that critical, it does run 24/7 but we can stop it if necessary, it is just that with A-B PLCs you can upload the program even in run mode, but I dón´t know about Siemens gear. Thanks for your reply...

 

[controlsdude]

I do not see it to be a problem to upload from the processor when its running. It looks like you can upload it from its db9 port.

I have done it on abs plc5, slc, contrologix, modicon, and siemens.

jraef was just talking about a registered copy of the programming software to upload. I think siemens is the most bizarre in getting it loaded on your laptop. Siemens Software keys are a pain.

 

[ozmosis]

cokeguy
Some bedtime reading:

http://support.automation.siemens.com/WW/view/en/22639716

 

[CanadianTaff]

You will need Step 7 to interface with the PLC. You can connect via MPI or Ethernet, if you connect by MPI you will need an adaptor.

You can upload and download to a running PLC.

There is no operational risks in uploading, but you may cause you comments to become misaligned (if you have the developement software). If you upload the code into a blank project, it will be OK as a back-up but not very good for fault finding.

If you download, you can cause the PLC to crash if there is an error in the code, like trying to access a data area that does not exist.

You can avoid crashes by adding fault OB's, but these should never really be left in, only when testing and commissioning.

 

[Unisphere]

The fault OB's are where you'd want to put your fault handling code surely, such as FB125 etc.

 

[CanadianTaff]

On a fault certain OB's are called, the OB called depends on the fault. For example OB121 for a Programming Error.

These OB's are not automatically functional in the code, they exist, but if you do not enter code into them then the PLC will crash under certain error's.

If you do create the OB as part of your project and download into the PLC, then the PLC will not crash, even if the OB is blank. Once the OB has been created, then a STOP has to be programmed (SFC46) to stop the processor.

The TEMP area of the OB's hold the diagnostic data.

There are blocks that can be used to interrogate further the problem.

It's quite common on commissioning to put in OB's such as OB121, but these should not remain in unless the consequences to not stopping the PLC is known and accepted or logic included to STOP the PLC.