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Old April 19th, 2017, 10:27 AM   #1
Rob S.
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Best and Easiest Brands of Wireless Ethernet Extenders

Good Morning ,

We have a fairly large plant. I have some new machinery , that product is fed from some equipment about 400 to 500 feet away. We would like to communicate with this equipment feeding this machinery. Instead of running fiber , I would like to use wireless to extend this ethernet network. I would like to set some AB Flex I/O at this machinery to share some information. I would like to find some bi-directional wireless ethernet extender kits. I thought that Phoenix Contact had them but I am having a difficult time looking thru their website. Part of it is my lack of knowing the terminology .

Example , my main machinery has a block of IP addresses it is using ....
192.168.200.1 thru 192.168.200.32 . I would like to extend this communication about 500' away and start with 192.168.200.33 , and so on.

Could you share a few links for some Wireless Ethernet and some recommended brands.

Thanks so much for your advice.
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Old April 19th, 2017, 11:17 AM   #2
mk42
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I would be cautious about using wireless for remote IO, unless you absolutely have to. What kind of RPI are you expecting to need? Standard wireless is fine for communication that will accept high latency, but it isn't usually good for deterministic control. You might be OK if you're just doing interlocks with the next system over. Some vendors have proprietary protocols that make things more deterministic/reliable for safety or real IO control (I've used the gear from Siemens).

If you do go down the wireless route (assuming we're talking about standard 802.11 wifi), you'll be looking at directional antennas for the point to point link. Depending on how they word things, you'll either want a pair of wireless bridges, an access point and a client, or two access points. You might be able to power them with POE, but that means you'll need a special higher voltage power supply for your switch (I think it's 54V?).
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Old April 19th, 2017, 12:00 PM   #3
Brian7424
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Try this https://www.phoenixcontact.com/onlin...02-02-01&tab=1
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Old April 19th, 2017, 12:04 PM   #4
James Mcquade
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Rob S.,

I can be wrong on this, if I am, some one please point that out.

I am not sure you can do what you want.
If you are wanting to connect the pc to the other end to look at the code, ok.
if you are wanting to control the machine 400 ft away with wireless communications.

you will need to look at nfpa 79 for sure.

E-stops must be hard wired, you can't get around that.

the problem I see is that you tell the machine to run.
3 minutes later, someone runs into the wifi and kills it, a brown out occurs, you loose power, or the wifi terminal dies.
30 seconds later, you have to stop the machine, oops, no signal to the other end so the machine keeps running.

you will have to get with management, safety, engineering, maintenance, and the operators and do a risk assessment. That will tell you how to proceed.

if at ant time, you tell machine A to start, stop, goto manual, or any thing and machine B located 400 - 500 ft away fails to recognize the command over the wifi network, that is an issue. If someone gets hurt, it will become a very big issue and very quickly when osha hits the door.

How far away from any airport are you???
there are restrictions on wireless network frequencies you are allowed to use if you are within a specified distance. We are restricted here because of that.
it's in the 5 ghz bandwidth.
regards,
james
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Old April 19th, 2017, 12:23 PM   #5
Rob S.
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I'm sorry. I should of shared this. I just want to capture what speed each is running , when one or the other is not running , etc. It will not be for control of any kind.

Thanks for all your input,
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Old April 19th, 2017, 12:31 PM   #6
harryting
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I wouldn't trust consumer level wifi extender. However, you can easily bridge the network by using one of the many industrial wifi-bridges. B&B's Ghostbridge is fine for that purpose.
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Old April 19th, 2017, 12:45 PM   #7
mk42
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Quote:
Originally Posted by James Mcquade View Post
you will have to get with management, safety, engineering, maintenance, and the operators and do a risk assessment. That will tell you how to proceed.
Agree, a risk assessment is probably the most important thing you can do.

Quote:
Originally Posted by James Mcquade View Post
you will need to look at nfpa 79 for sure.

E-stops must be hard wired, you can't get around that.
I've seen done safety over wireless before, at least on Profinet. I've even seen wireless mobile pendants with E-stop buttons. I think there's some general clause in NFPA that says something about not getting in the way of progress/state of the art.

Certainly requires a safety rated PLC & IO, though, and there are a while lot of rules to follow to meet a certain safety rating (usually specified from the results of the risk assessment).

Quote:
Originally Posted by James Mcquade View Post
the problem I see is that you tell the machine to run.
3 minutes later, someone runs into the wifi and kills it, a brown out occurs, you loose power, or the wifi terminal dies.
30 seconds later, you have to stop the machine, oops, no signal to the other end so the machine keeps running.

if at ant time, you tell machine A to start, stop, goto manual, or any thing and machine B located 400 - 500 ft away fails to recognize the command over the wifi network, that is an issue. If someone gets hurt, it will become a very big issue and very quickly when osha hits the door.
One of the things to do to make communication safe is to make sure watchdogs are in place to shut things down if needed. If you haven't had a message in a while ("a while" is determined by your risk assessment), you simply shut down or go to your safe state. You don't send an edge command to change modes, as that can be easily missed. Instead, you send a maintained enable signal for the mode you want to use. When the watchdog decides comms have died, it makes the enables false anyway.

The trick here is making sure your comms are reliable enough that this failsafe watchdog doesn't impact production. Over Ethernet, that's not too hard. Over wireless, it can be a bit trickier, you just need a well designed setup (and maybe the right equipment).

Quote:
Originally Posted by James Mcquade View Post
How far away from any airport are you???
there are restrictions on wireless network frequencies you are allowed to use if you are within a specified distance. We are restricted here because of that.
it's in the 5 ghz bandwidth.
regards,
james
This is probably the U-NII-2 band. You may still be able to use it if your equipment supports DFS and TPC. Essentially Sattelites & Radar have priority there, and the wifi gear needs to turn off or find a new channel if it detects the Satellite/Radar signals. You might not be able to use it outside but most factories I see are built like bunkers (giant faraday cage) that keeps the outside signals out and the inside signals in.
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Old April 20th, 2017, 03:17 PM   #8
Firejo
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Wireless Ethernet (not to be confused with WiFi) is very much a “you get what you pay for” technology. If you use consumer grade technology you’re going to get consumer grade quality which is typically not what you want in an industrial automation application. There are two basic types of wireless Ethernet modems out there, WiFi and Frequency Hopping Spread Spectrum (FHSS). WiFi is much faster and carries a much high bandwidth but isn’t nearly as robust and reliable as FHSS. FHSS is very robust and reliable (although different manufactures have different levels of quality) but is much slower than WiFi.
This product will give you an excellent connection at 500’ which not all WiFi type radios can say.
http://www.data-linc.com/HighSpeed/index.htm


This is a different approach. Instead of trying to communicate from the PLC to the remote I/O via Ethernet you would be communicating from the PLC to the Protocol master via wired Ethernet and the Protocol master would gather the data from the I/O. The connection between the master and the I/O remotes isn’t WiFi is FHSS so the I/O link(s) is very stable but you still get Ethernet connectivity to the PLC.
http://www.data-linc.com/plantlinc/plr6400.htm
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Old April 20th, 2017, 08:19 PM   #9
Old No. 7
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We've used these for remote I/O before. They seemed to work pretty well.

http://www.prosoft-technology.com/co..._Datasheet.pdf
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Old April 20th, 2017, 08:30 PM   #10
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Quote:
Originally Posted by Rob S. View Post
Instead of running fiber, I would like to use wireless to extend this ethernet network.
I'm just curious as to why? If it were my choice, I'd go with the fiber.
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Old April 21st, 2017, 07:49 AM   #11
Baker in Virginia
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I was thinking cost . I would imagine fiber would be more expensive, with fiber and labor ?
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Old April 21st, 2017, 05:51 PM   #12
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It sounds like this is just for monitoring. Wifi should work for for you. Check out Ubuiquti
https://www.ubnt.com/

You can set up QOS so that control traffic takes priority.

PLC-PLC messaging normally works fine. Remote I/O can work, I have Modbus TCP remote I/O operating over a UHF radio link for monitoring a water pipeline flow and pressure, that updates once a second. Plenty good enough for my needs.
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