Backup PLC program using DirectNet

rhung · Oct 31, 2003

We developed a DirectNet device driver for the the Koyo/Automation Direct PLCs, and we can access the PLC memory.
Is there any information on how to backup and restore the PLC program? It should be just another memory area inside the PLC.

Thanks for the help.

Steve Bailey · Oct 31, 2003

While many PLC makers will publish the details of how their protocols handle data transfers, most are reluctant to divulge how they handle programming issues.

Since Automation Direct's programming software is quite reasonably priced, especially when compared to some of the other major brands, why bother trying to 'roll your own'?

rhung · Oct 31, 2003

We developed a PLC Maintenance product which allow users to schedule backup, perform restore, sync. the clock etc, thru the network with auditing features. Now we are adding support for different PLC models....

kamenges · Oct 31, 2003

The company I used to work for developed a custom coprocessor module for the DL 405 family of processors. It resided in the backplane and communicated with the plc like it was another intelligent module. The guys at Koyo were very cooperative with info and support during this process.
Now, granted, Koyo didn't have anything that competed with this like your software might. But I would contact Automation Direct and see if Koyo will license you the functions for upload and download. Then you can use them as function calls from your application and you don't need to know the details of the transfer mechanism. It just does it and comes back pass/fail. As long as you don't want to design an new development environment I don't think they would have a probelm with this.

Keith

rhung · Nov 3, 2003

Thanks Kamenges, that is nice to know, we will find out who to contact in Koyo.

AndyT · Nov 6, 2003

I hope this is not too late but Host Engineering (writers of DirectSoft) already has a utility which will up/down load the ladder to Automationdirect PLCs. The currect version only supports serial comm however they are currently adding ECOM support to it. Best of all it is free.

Email [email protected] for more information.

Hopes this helps,

Andy

rhung · Nov 6, 2003

Thanks Andy, our system is a pure Java application and our customers are running it on IBM AIX and HP-UX. That is one of the reason why we cannot depends on Windows components.

Anyway we just find out that we might be able to use the DirectNet protocol to upload the ladder program. That feature just not documented in the DirectNet manaul.

AndyT · Nov 7, 2003

Understood sir. Yes you can use Directnet protocol to upload/download ladders. Use data type 37 in your header to access ladders. I do not know if you intend to write ladders to the PLC but one drawback of the protocol is you must put the PLC in the stop mode to do so. This requires writing to scratchpad memory, data type 36. Reading ladders from the PLC does not require this.

Andy

rhung · Nov 7, 2003

Is there a way to determine the size of the ladder program memory area? According to the document the DL405 430 is 3.5K, 440 and 450 can be 7.5 or 15.5K. But when we did the testing on a 430, it allows us to read pass the 3.5K boundary.

AndyT · Nov 7, 2003

Yes there is. It resides in scratchpad memory, data type 36. Address (Hex)102. This is a read only location of course. Check the low 3 bits of the byte and see if this gets you what you want.

Andy

rhung · Nov 7, 2003

We tried that one a D430, the value of that byte is hex 28, so the low 3 bits are zeros. Where can we find the memory map information for the scratchpad? We couldn't find it in any documents.

Thanks

AndyT · Nov 10, 2003

Bit 2-0 : Program Size of MC ( for D405)
(000) = 4k words / (001) = 8kw / (010) = 16kw / (011) = 32kw

When looking at the memory size remember that 0.5K is required for system memory so 4K memory size will allow 3.5K ladders.

Hope this works for you, please let me know.

Andy

rhung · Nov 10, 2003

So the value is correct, we tested it on a DL405 model D430, the program memory size is 3.5K (4K with the 0.5K used by the system), and the value of the Bit(2-0) is (000).

How about the rest of the scratchpad? Is is possible to get a memory map of it? It seems that a lot of undocumented information are stored there. It would be nice to know the model type of the PLC, the actual number of steps in the ladder program, whether the optional memory cartridge is installed, etc.

Thanks.

AndyT · Nov 10, 2003

Yes that should be the correct value for a 430. I do not think you will be able to get the updated specification. Koyo considers that confidential. You could try and find one of the old TI/Siemens 405 DCM manuals. Some of the scratchpad info was published in that document however it will several year old information and many additions have been made to the scratchpad.

If you would like to email me with specific questions I will answer them where possible.

[email protected]

Hope this helps,
Andy

rhung · Nov 11, 2003

Thanks a lot Andy, I will try to look up the manual.

Backup PLC program using DirectNet

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