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Rod_Hackney

Ethernet Switch manufacturers

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The company I work for is opening a new facility and it provides the opportunity to install ethernet network from the ground up. Most lines in the facility will use ControlLogix processors with a few other manufacturers PLCs mixed in. We currently use Moxa ethernet switches at our other facilities but wanted to get the forums opinion on ethernet switches and your experiences.

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From the Chrysler Plant Preferred Specification List. I have worked with both Hirschmann and N-Tron, both worked very well for our ControLogix applications. EtherNet Switch, Hirschmann, RS2-TX, 8 port Ethernet switch EtherNet Switch, Hirschmann, RS2-16, 16 port Ethernet switch EtherNet Switch, N-TRON, 516TX-A, 16 port Ethernet switch Bud Edited by BudMan

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Plan on 6A copper and the assocaited fiber hardware if you can free up the dimes.

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I like the Hirschmann models because you can set them up (along with CLX I/O) to be truly "plug-and-play". You can buy an "ATA" which is a memory stick type device and save all the settings from the switch onto it. If a switch fails, an electrician can simply replace the switch and plug in the "ATA". On boot up, it restores all the same settings identical to the original setup. For the end devices, use HaneWin DHCP. You can have multiple DHCP servers (for failover reasons) and you can establish per-port IP address assignments instead of the much more limited per-device IP addresses. Then if a network card fails anywhere in your CLX system, the address will be automatically restored when you swap cards. There are no dip switches, etc., to fool with. One warning that I do have. Watch out for many differences between the "Lion" and rail switch lines from Hirschmann. The "Lion" series is intended to compete toe-to-toe with Cisco and lacks a lot of the features that the railswitch (plant floor based) switches have. If this is a new setup, I'd go for a 1 Gbps 50 micron multimode fiber ring for the plant backbone. If you use single mode, you will pay a lot more per node for transceivers. Single mode only makes sense once you start going for kilometers of distance. And you can expand your fibers in single mode with CDWM or DWDM. In multimode, 62.5 micron is more popular but can't support 10 Gbps while 50 micron can. In the individual I/O networks, I'd go for CAT 5E and 100 Mbps. Might as well have the speed now while you can get it. Many people are pushing CAT 6 but it's an orphan. 5E can support up to 1 Gbps (10 Gbps over short runs). 5E supports up to 100 MHz spectrum while 6 does 250 MHz. BUT, the 10 Gbps copper Ethernet standard doesn't go any further on CAT 6 than 5E, making CAT 6 effectively an "orphan". We won't see 10 Gbps copper going more than a few meters until both the connector (RJ-45 is one of the limitations) AND the cabling change, which is what the proposals for CAT 7 are all about...so save your money on CAT 6 unless you can get it for the same price. The only nice thing about CAT 6 is that it pulls easier (more rounded).

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I have used alot of the Hirschmann Spider5TX switches. Never had any problems and they are cheap -- around $100. Also the N-TRON switches, made in the USA. They have a nice 105TX switch, metal case, small size. Should be able to get those for around $90.

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We have used the Hirschmann Spider series, mainly 1FX4TX version. We use FO for interbuilding/longer runs and copper locally. Once you have invested the pennies(cents!) in the FO termination kit (We use LightCrimp+) running FO is easier than copper in many cases as you can run it on the same cable tray as the cable feeding that 50kW motor! The Hirschmann units have worked first time, straight out of the box. They also do a nice line of managed switches if you application is more demanding.

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Thanks to all that replied, I will checkout the suggested manufacturers. We are planning on going with fiber and the suggestions here will be helpful.

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I hate to befuddle the subject but it seems everyone is biased on the Hirshmann brand...not that there's anything wrong with it but there are more options... but for $125.00 USD you get an industrial strength ethernt switch that has all of the Certifications including Canadian CSA that the Hirshmann doesn't..(still pending certification)..This was import to our canadian customer because our PLC panel wasn't decalred CSA certified unless every device in our electrical panel had a CSA label on it. This may not apply to allot of you guys, but our customers are internationally aroung the world, so this switch suites all of our customers, thats why we standardized on it.. http://search.bb-elec.com/?q=6520&Imag...amp;Image10.y=4 5 PORT INDUSTRIAL ETHERNET 10/100 SWITCH REQUIRES 10 TO 30 VDC POWER SUPPLY DIN RAIL MOUNT B&B PART #ADAM-6520 Edited by jimdi4

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I don't know if this matters or not and I doubt you'll be able to find the document anymore (it's tough to locate) but early on in the Ethernet/IP development, Rockwell did a round of "test everyone against each other". From that test, they more or less blessed N-Tron, Cisco, and Hirschmann. By the following year, Rockwell had signed their distributorship-type agreement with Cisco and ever since then, the only "recognized" brand that Rockwell will mention is Cisco, IN SPITE OF THE FACT that in terms of industrialized equipment, Cisco is decidedly not my favorite. Their only managed offering is essentially a cheesy version of their mid grade switches. And their unmanaged ones are almost the same as what they are selling in Walmart. Based on that information, I stuck with Rockwell's original list of "decent" manufacturers. ADAM stuff has been out for years in various flavors but since it looks/smells cheap (sold through Automation Direct for instance), I've been a little afraid of touching it.

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Paul - what's wrong with using Cisco 3750s (besides price)? When "installing an Ethernet network from the ground up" (OP), your equipment will reside in an air conditioned room.

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Several items. 3750's are nice don't get me wrong. But, there are other things to consider: 1. If you want the advantage of RSTP/STP/ring recovery protocols in your I/O area, RSTP will recover in 1-2 seconds typically. The various "ring" networks, though proprietary, recover in under 100 ms, fast enough that a cable failure will not be detected by your I/O. In addition, Cisco's RSTP/STP is kind of "strange". It implements RSTP over each VLAN (with fallback to the standard) and their own proprietary protocol rather than implementing the standard. You can still make it work but it's not the default configuration. 2. What is the technical prowess of your technician/electrician staff? If they are computer-savvy, then use the Cisco stuff. If not, then use the ATA's that you can get from Hirschmann or equivalent. These are essentially memory-dongles that hold the programming on the switch. Replacing a switch is a matter of swapping hardware around and turning it on, no saving/loading of files needed. 3. How difficult is it to set up bandwidth throttling and priority queueing, both of which are all but necessities? You can do it with the 3750 but you'd better be very Cisco-savvy. Most other switch manufacturers have made the switch software much easier to work with than the Cisco CLI. 4. Do you need/require redundant power supplies? If power reliability is a problem, you have to address this external to the switch. 5. How can you monitor and respond to network problems from within the controls network? Cisco doesn't have external relay contacts, OPC, Modbus/TCP, Ethernet/IP, or anything like that. Instead you've got to get creative with SNMP, something very foreign to controls network protocols.

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Rockwell suggests Stratix switch.

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A big factor to consider when choosing a control network hardware solution is...managed or unmanaged switches. PLCs and other industrial control hardware are notorious for flooding networks with broadcast traffic. Managed Ethernet switches give the administrator the ability to limit traffic between devices/switches. Along the same line is who will administer this network. If you, the control engineer, are in charge of your network, then it is your choice. If IT will be covering you, it is best to get their buy-in or start to rally the troops to stake your case for your own preferred hardware solution.

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