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Cheap Solution

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I need to control and monitoring a system 200 mts away, and i can't use fiber cause is to expensive. I think on micrologix, but i can't choose some cheap way to communicate them. Any suggestion? help please... :-8

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Well, i was reading my question and it's too difuse so i'll try to explain it better. I have to install a remote system under control with 2 or 3 digital signal and 1 analog I/O. This system is 200 mt away from hmi command center. The other signal arrives by ethernet using fiber. The natural solution seems to be ethernet using fiber between the new remote system and command center, but it its to expensive comparated with total cost of control solution. Is there another way(protocol) to connect them???? thanks again!

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I assume you mean digital comms between two systems. In other words, the analogue and digital inputs will be into a local system which then has to communicate the data to another system 200 meters away? Use good old RS-422. You can do 200 meters standing on your head.

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You're thinking about it wrong. You should approach the problem saying "gosh, controllers sure are cheap compared to the cost of fiber !" A agree that an RS-232/422 converter (make sure it's capable of 4-wire or "full duplex" if you want to use DF1 with the MicroLogix) is probably the simplest way to go. But installing 200 meters of conduit or cable is always going to be more expensive than a small controller. I don't care if you're digging a ditch using migrant Mauritanians, labor is the highest cost in installations.

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Do you have line of sight, if so you could use a wireless solution the install is generaly easy and 200m is not that far easy to find a wireless solution in Ethernet devicenet ....... rs232 rs422 ect ect...

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I am currently working on a similar application. We have decided to use wireless I/O. There are lots of options, but we are going with a unit in the field, and a wireless gateway with DF1 communication to a Micrologix PLC. The cost of the wireless hardware is going to be around $3500.00. The price for hard wired system was around $20,000.00..Easy decision Ken

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Go wireless! I have to maintian wells that are 1 mile from the plc. The digital signals are a on going problem. The system is in the mountian and has taken some lighting stikes.

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Another option is Ethernet cable using the Lantronix DR-IAP Device Server $800 for two boxes just need the ethernet cable between the two. They communicate using the RS-232 ports on the PLC's but the boxes translate DF1 to standard Ethernet Protocol.

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Are you sure that Ethernet will work for 200 meters ? I thought the physical maximum for 100BaseT was about half that.

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thanks all for your answer, i'm evaluating wireless right now, i'll tell you what decide finally and what result i have.

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