S7-300 Power Loss Problem

Hi guys,

I have a client wich keeps telling me to give him a solution to his problem.
The problem is that he has an automation with a S7-300 and to VSD's that controls some motors.
When there is a power loss(and this happens regularly) the PLC enters in Stop mode and needs to be manually put into Run. I don't have experience with Siemens PLC's so can u tell me what could be the problem here. Can be something with the software, or it's a hardware problem and the plc enters in Stop and stays there because of the repeated power losses?
I don't even know if the PLC is accesible, they say they don't have any cables for programming or something else. From what i know i need an adaptor to connect to a siemens PLC.

The ideea is that i don't know what to offer him. I thought that an option will be an UPS in front of the PLC for protection to the fenomens created by this power losses.

What are you thinking about this? As i said i'm not so experienced.

Thanks in advance!!

There is a good chance it could be a software issue...for a starter do you have "Siemens Simatic Manager" software?. With this application you can check the diagnostics of the PLC which will give an indication as to what the problem is!

LH

Longhorn said:

There is a good chance it could be a software issue...for a starter do you have "Siemens Simatic Manager" software?. With this application you can check the diagnostics of the PLC which will give an indication as to what the problem is!

LH

Click to expand...

We don't have a license for Simatic Manager for now because we don't use Siemens at this time. Can i do this with Step 7 Lite? I think this is free.

I read somewhere that it can be that the plc generates an error and it loads this error on one of the error blocks : ex:OB86. If the software doesn't have this error block then i can fix this by connecting to the PLC and download only this block to the existing program. Is this true?

Also I know that the software can be protected. In this case it is true that i cannot access it by any means?

Thanks for your reply.
With respect,
Ionut Capitanu.

I have never used s7 lite but looking through the spec it looks like you can check the diagnostics on an s7 300. If an organization block is missing or perhaps some code exists in an ob which is causing this problem, the diagnostics will help diagnose the problem.