Help required please.

I need to communicate with an industrial Hot-Melt Glue controller from my 314 CPU. The manufacturer of the glue controller has issued me with their RS485 protocol document which basically dictates the header information and various other parameters I will be dealing with. Unfortunately their RS485 connection operates at a BAUD of 38400bps. I do have a Simatic RS485 terminating unit (6GK1 500-0AB00) that I was going to use to connect to this device, however I have just realised the problem with the mismatched baud rate, as the standard baud options available on the profibus settings do not allow this rate to be selected.

Is there any kind of industrial interface unit available that I could use to interface the two? Or if someone else has any kind of suggestions at all I'd be happy to investigate.

Many thanks in advance for any help.

Matt.

Hi Olloy,

I have to admit that this is a last minute job thats been handed down to me, and I have no experience dealing with non-Siemens devices through profibus. I know that there are standard FBs available to send and receive but haven't used them before.

I have attached the only reference documentation that I have for setting this up.

The manufacturer of the hot-melt unit have today said that their interface is "a standard RS485" which is all the information that they were able to provide me other than the document I have attached.

Any suggestions and information gratefully received.

Matt.

Dear globaltech,

it's not profibus you are dealing with. You will have to adapta vendor specific protocol by usingthe standard ASCII driver (send/receive function blocks) of thesiemens serial interface.

Best Regards.

Hi olloy,

the max. baudrate for CP340 is 19.2kBaud, if that Xmelt system cannot reduce the baudratehe will need to use CP341.

Anyway, I believe that problemhas a lower priority now.

Best Regards.

Thanks for the input guys, a couple of things to put forward.

The control cabinet for this machine is already overstuffed with components that we physically can't fit a CP341 unit in there! As silly as it sounds there is no available Din rail space!

Whta I've found is a local supplier of Profibus - RS485 adapter units that are small enough to fit inside the hotmelt unit. They are bringing one along for me to try tomorrow. I am hopefull that this will solve my problem. There is still the issue of sorting out the message frame, which I guess is the bigger issue right now, however this magical box promises a very user friendly setup interface, so I'll see what transpires with the rep tomorrow.

If as I suspect this magical box is not as magical as they say, then if anybody could pass along an example of using standard FBs to communicate over profibus that would be great. Otherwise I'm back to the Simatic help files and the lovely people at the Siemens UK helpline!

TIA.

Matt.

Hello Matt;

If your Melt module is not certified as a Profibus slave, if it does not have a Profibus gsd file so it can be integrated in a Profibus configuration, if the network frames and baudrate do not match Profibus standards, it looks like you are grasping at straws here. I do not know of a way to reprogram the Profibus communicationsprocessorsto match a non-Profibus partner.

If Profibus is avaliable in your cabinet, you should look rather in using an ET 200M remote I/O station outside the cabinet (a small junction box with an IM 153-2 head module) in which a CP 341 can be inserted. You can then program this CP 341 for ASCII communications with your Melt module, as if it were on your main rack.

Or use a gateway from Profibus to ASCII RS-485, there are a few available from reputable manufacturers on the web.

Think about this after your tests with the magic interface.

Hope this helps,

Daniel Chartier