Simple Ethernet I/O needed


Thread Starter


I have a PC which monitors some lab equipment and needs to produce an alarm on the DCS upon certain events. Ethernet already exists between
the PC and the room in which the DCS input racks reside. I would like to close a dry contact via Ethernet from the pc using Winsock, OPC or
some other simple means to provide the signal to the DCS. Can anyone recommend a simple standalone Ethernet I/O that can accomplish this

Michael R. Batchelor

Intelligent Instrumentation makes standalone Ethernet I/O which should be able to do exactly what you want. I've only used their 4 port serial device myself, but they have digital bricks as well. (And analog, too.) The serial device is actually pretty easy to use once you go through their code samples. I imagine the digital should be easy, too.

Michael R. Batchelor - Industrial Informatics & Instrumentation, Inc.
Linux is like a wigwam... No windows, no gates. Apache inside.
Enter "ethernet i/o" on Google search and have a field day. Opto22, National Instruments, Wago, etc., etc. Beckhoff makes "Bus Terminal"
which is highly modular (you can scale it down to a minimum, which is probably what you want).

Any Ethernet I/O device will require configuration software at least. Getting your PC to transfer data between the I/O and your existing software could be troublesome depending on what you're running on the PC. If it's fairly robust, it may support a selection of remote
I/O...check on this before you commit to hardware. If the PC software doesn't support remote I/O, then OPC or some other open standard
(including maybe some custom programming) will be needed to transfer data from the lab software to the I/O software, IF your existing lab
software supports open connectivity.

Depending on what you're running on the PC, establishing communication to the Ethernet I/O may not be at all trivial, and may not be
justifiable for just one contact output, unless it is a very important contact output.

Curt Wuollet

I'll bet Optimation or Opto22 could, Optimation being much cheaper but using an obscure (but documented kinda) protocol The Opto22 product can be used with Modbus/TCP or their own proto.
IIRC Sixnet does this also.

Instead of Ethernet I/O, I am using a small PLC with a modbus protocol integrated, and a TCPIP/RS485 converter.
The complete solution is less than 900 Euros (800 US$).
The PLC is master in modbus protocol.

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