rs-232 to ethernet tcp/ip and dh 485

  • Thread starter Jose Luis Glomba
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Thread Starter

Jose Luis Glomba

We have two AB slc 503 and 4 panelviews connected togheter on a rs 485 network using dh-485. There are not empty slots on the plc and they don't have a ethernet connector. That we want is to connect it to our ethernet network. Any idea of how we could do that? Our first thoughht was to use an ethernet to RS 232 convertor but we don't know if that kind of devices could support the dh-485 protocol and we are not able to change that protocol. Any help will be appreciatted . Jose Luis
The best solution would be to swap out the the 503 processors with 505 processors which makes channel 0 ethernet. You should be able to use channel 1 for your DH485 devices.
DH485 is a token bus and has such tight timing expectations that it cannot survive either radio modems or Ethernet. If you place an Ethernet in the "middle", you'll end up with 2 tokens (one at each end) which also cross the Ethernet and kill each other off. Each ring would eternally think either the token was lost & creating a new one or be seeing 2 tokens. Can the SLC5/03 "bridge" between CH0 (to DH485) to CH1 (to DF1 Full Duplex)? If it can do this (maybe you need to update the SLC firmware), then you can use either one of our Device Servers with raw DF1 encapsulated in TCP or Rockwell has released the ENI1761 which maps Ethernet/IP/CIP to DF1. I've seen people do this bridging thru the DF1 port of SLC5/04 to DH+, but I'm not sure about the SLC5/03 and DH485. Regards Lynn August Linse, Senior Product Application Engineer 15353 Barranca Parkway, Lantronix Inc, Irvine CA 92618 [email protected] Tel: (949)300-6337 Fax: (949)453-7152


Try this: Select one of the 5/03 machines to gather all of the data to using MSG instructions over the DH-485. I posted a method of doing this on the plc archive ( some time ago. Use a simple PC with a serial port into the RS-232 port on that 5/03. Write a small app in whatever language you are comfortable with to talk to the PLC with DF-1 protocol, which is published by AB. Make this data available to the rest of the network via DDE, a database, or whatever is appropriate. Should be doable for less than the cost of the 5/05..... --Joe Jansen


Maybe so, but at an $1800 premium, that makes it probably THE most expensive 10BaseT ethernet adapter I've ever come across.
I'll say about Lynn Linse what somebody once said about George Stephanopalous; "If IQ were Fahrenheit you could boil water with the guy". I'm eager to test out a 1747-KE with the 1761-NET-ENI; I'm not certain if those two devices together would effectively bridge Ethernet to DH485. It's moot in this case because there are no spare slots. The SLC-5/03 does not pass through data from DF1 to DH485. The SLC-5/04 and SLC-5/05 have this function when Channel 0 is in DF1 or DH485 mode (and the function is enabled in the status file), but the SLC-5/03 does not. If one of these controllers was replaced with a 1747-L531 processor, then Channel 0 of that processor could connect through a 1761-NET-AIC isolator to the DH485, and the other controllers (and probably the PanelView, this depends on PanelBuilder) would be accessible via Ethernet and ENet/DH485 passthrough function. >>We have two AB slc 503 and 4 panelviews connected togheter on a rs 485 >>network using dh-485. There are not empty slots on the plc and they don't >>have a ethernet connector. We want to connect [the DH485] to our ethernet network. Ken Roach Tech Specialist A-B Seattle

Michael Dannhardt

I'm not sure what you have on the other end that wants to talk to your AB equipment but if it (they) support OPC: Use a OPC Server program(s) that talks DF1 via rs-232, place a terminal concentrator (Lantronics for example) near the PLC network and place a KF3 at the rs-232 output. The terminal concentrator acts like a remote port rs-232 for the OPC Server's computer and the FK3 gets the DF1 rs-232 onto the DH-485. Then you have connectivity between the OPC Server and the DH-485 devices. OPC clients can get/put data via the server. Mike Dannhardt DASTEC Corporation From: Michael Dannhardt, DASTEC Corporation Address: 457A Carlisle Drive; Herndon, VA 20170 USA Tel: 703 709 0515 Fax: 703 709 0985 E-mail: [email protected] Web:

Harry Friemann

Dear Jose, I am investigating a device called Unigate from Deutchmann, it support amongst others a transparant protocol, perhaps you can use it for your application Sincerely yours, Harry Friemann Assistent Technische Informatie Systemen BCcomponents, afdeling R&O Tel: +31 38 4575 317 Fax: +31 38 4575 298 E-mail: [email protected]
AB announced a new DF1 to Ethernet bridge it will directly connect to your DF1 port on the 503 and provides a 10BaseT Ethernet port. See Best Regards Rolf RG Electrical Engineering & Consulting PO Box 37601, Winnellie NT 0821 Australia Tel: ++61 (0)8 8984 4385 Fax: ++61 (0)8 8984 4001 Mobile: 0417 837 933 Allen Bradley System Integrator Rockwell Strategic Software Provider
To connect a MicroLogix (or other PLC) to a DH485 network, an Allen-Bradley device called an AIC+ (Advanced Interface Converter) is used to
provide connectivity to the RS-232 port to the DH485 network. At that point AB RSLINX will be able to communicate to each PLC on the DH485
network using the built in software driver selection. Getting on ethernet is even easier if you virtualize the com port using Lantronix
devices that provide transparency... RSLINX thinks it is looking at a com port.. it's virtualized!!