How much data do you need to transfer? How fast?
Profibus, limited number of registers but you can multiplex them.
Hardwire, really limited but could be all you need for two or three
Serial, use Modbus to transfer an almost unlimited number of registers.
I think the S7 serial module also supports some of the more basic AB
Multiplexed hardwire link, say 16 bits of data and maybe 8 bits to
If you are braver still, try connecting them together over Ethernet...
Hardware required: two modules, one CP in the S7 rack and one Prolinx
module in the logix rack. The S7 CP will need some special Modbus
software and licenses. The S7 Modbus software needs to be ordered as
Master or Slave and you get a tiny blue dongle that plugs into the CP
that I suppose indicates you paid for it. The S7 is programmed using
functions that will read or write quite a bit of data, up to the Modbus
limit per packet (128 words I think). Add more function calls to get
more packets. It was easier than I anticipated, Siemens have really got
their act together with the S7 - you even have access to FAQs and How-
The logix side I am not so sure about - check out the Prolinx site.
http://www.prolinxgateways.com/content/view/full/621 will take you
straight there. The S7 module needs to be ordered to be RS232 or RS485
or (shudder)20mA loop. If the logix prolinx is like the stand-alone
prolinx converters then the module should support both RS232 and RS485.
This sounds like a very interesting project. I wish you many hours of
I would use Profibus DP due to higher transfer rates. The
multiplexing, mentioned above, is easy. S7-3xx have Profibus DP built
in. The ControlLogix requires a Profibus DP card. Search for
ControlLogix Profibus DP and you will find many links.
Finished a job not to long ago where Siemens S7, AB ControlLogix, and
DeltaV had to communicate. We used Profibus DP.
Both DeltaV and S7 required they were the master. So all three systems
were set up as masters, and we used DP/DP couplers to allow them to
communicate. This is a simple device that allows multiple masters to
talk to each other by acting as a slave on both ends. Sorta like an OPC
mirror application, but it was a nice, simple hardware box.
Commincations were fast and flawless.
Peter Nachtwey wrote:
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