Diffrence between RS232, DH+, DH485 & Ethernet

Hi, Signode!

Not an expert in this area. But I seem to recall that RS232 is a multi-pin connector using a line between the PLC and a readout device, and the Ethernet is a card that allows communication between devices via either wired or (bluetooth) wireless transmission. Someone who really knows may be able to expand on this, and give you the lowdown on the DH stuff as well. Have you tried any of the search engines to see what you can find there?

Mark

Hi Signode,

RS232 is a serial comms network and comms in various forms and baud rates from 1200b ro 115.2kb. In its simplest form it can use 3 wires, a ground/common a transmit (Tx) and a recieve (Rx), normally it is only between two devices but it can be used in mutiple devices.

DH+ and DH485 are Rockwell protocols. DH485 is used with low end SLC5's and relevant hardware, uses 6 core cable, uses a 19.2k baud rate with up to 32 nodes, maximum length of 4000ft and is token passing from memory. DH+ uses a 2 core shielded cable referred to a 'Blue Hose', baud rates of 57.6k, 115.2k (not common) and 230k, up to 64 nodes but that is not recommended, up to 10,000ft at 57.6k and is token passing. Requires end termination resistors but I have seen networks that have no resistors and run okay. Both DH+ and DH485 require specialise connection modules for PC's.

Ethernet is now a common choice of comms for PLC's, runs at higher baud rates and is suited to larger amounts of data. Wire and hardware can be standard hubs and patch leads from the local computer shop or go to a higher level of redundancy and security. Unshieded Twisted pair (UTP) cable can be used or you can go to Shielded Twisted Pair (STP) or fibre-optics if noise or distance is an issue. A variation is Ethernet/IP (Ethernet Industrial Protocol) is an industrial networking standard that supports both real-time I/O messaging and message exchange.

It was very helpful dear

Very good and In Depth Explanation, Thank you Sir

If you're interested in converting between DH+ DH485 and Ethernet networks, I would suggest checking out some of these rather useful sites on DH Ethernet converters:

http://www.gatewayinterfaces.com

http://www.gatewaytech1000.com

http://www.gateway-1000.com

Hopefully they'll provide you with what you're looking for. And let me know if you have any questions.

Thanks!

2 of the links that you have provided are broken, the last one belongs to datalink which is not a real company.Morgan Jack the only known principal and employee of Datalink Technologies, (AKA about a dozen other Aliases), Which may manufacture and does sell the GW1000 that is based upon technology stolen from Equustek.

More info on http://bridgesandgateways.com /http://equustek.info

Anyone who needs a gateway between DH+ DH485 and all the other networks should contact original manufacturer Equustek Solutions Inc