Wireless Ethernet CompactLogix

I have 3 mobile machines that have CompactLogix PLC's and instead of using temporary Ethernet cables I would like to have a wireless router in each cabinet that connects back to our plant floor wireless network. Has anyone done this before?

It works well as long as you use good wireless hardware and aren't using it to control large amounts of remote IO. If you use home-grade wireless routers, prepare to have issues.

Helliana said:

It works well as long as you use good wireless hardware and aren't using it to control large amounts of remote IO. If you use home-grade wireless routers, prepare to have issues.

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I very much agree with this. If you are using consumer grade equipment in an industrial environment, expect issues. Office grade equipment will give you the performance you need, but you might void the warranty if you use it in a standard messy industrial environment. I'd recommend industrial grade equipment, probably IP65/67.

If you are communicating EthernetIP, I'd strongly recommend that you use it in unicast mode, if possible. Multicast + wireless = lots of wasted bandwidth.

mk42 said:

I very much agree with this. If you are using consumer grade equipment in an industrial environment, expect issues. Office grade equipment will give you the performance you need, but you might void the warranty if you use it in a standard messy industrial environment. I'd recommend industrial grade equipment, probably IP65/67.

If you are communicating EthernetIP, I'd strongly recommend that you use it in unicast mode, if possible. Multicast + wireless = lots of wasted bandwidth.

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Do you have any suggestions for the equipment to use?

If you have a plant floor wireless network already, check to see if that vendor has industrial rated equipment. It might already be what is installed.

If not, the first 4 companies that came up when I googled "industrial wireless networks" were ntron, moxa, siemens, and cisco.

I mostly used siemens plcs, so i typically use their wireless products as well, and have had few problems.

(As i'm sure you know) Cisco is the big player in the office networking world. I've never used their industrial grade gear for wireless, but I'd be shocked if it didn't suit your needs.

If you see any gear rated for "Outdoor" that is probably close enough, but note that outdoor gear is licensed a little bit differently than indoor gear, and you might have to change the default settings to stay legal with the FCC.

I would strongly recommend that you keep your PLC wireless network separate from your office network especially if the PLC’s are going to be talking with each other. The PLC’s don’t need to compete with all of the other WiFi equipment in the area. It is also a good idea to stay away from consumer grade products. They are built by the hundreds of thousands and quality typically isn’t the highest priority. They also tend to be very low power so range typically is limited. However, that kinda becomes moot as I would also stay out of the 2.4GHz and 5.8GHz frequency bands (which is where all of the consumer products will be). The 2.4GHz band is crowded and most of the time is heavily controlled by IT and the 5.8GHz band requires pristine conditions to work well.
This will do the job and stay out of IT’s hair. They operate in the 900MHz band and at an RF power of 316mW (25dB) which makes them very robust and reliable (compared to 2.4GHz) and they are a lot more flexible when it comes to line of sight (at shorter ranges).
http://www.data-linc.com/pdffiles/fastlincpdf/flc910eHiRes.pdf

Firejo makes some great points. I had assumed the network you wanted to connect to was already part of a larger automation network. If it is part of the office network, you almost certainly don't want to mix the two.

2.4 Ghz is definietly crowded, and you should avoid it if you can. 5GHz is often better, but you still probably need to coordinate the specific frequencies you are using with your IT group.

However, a word of caution: 900MHz solutions are wireless in the sense that they don't have wires, but they aren't "wifi" like your computer/phone would be able to communicate with. They might still work, if you aren't planning on connecting wirelessly with your laptop.

Ultimately, what are you trying to do? You said you wanted to connect them to the bigger network, but not what you wanted to do it for. Are you trying to program them remotely? Get data up to a higher level HMI/SCADA/MES type system? Do you simply want the plcs to be able to talk to each other?

Prosoft make some decent gear too. You will need to sit down before you open the quote, and as FireJo and mk42 describe above it's not your standard WiFi, so you need a sender and a receiver with the receiver hooked into your plant network. But from all accounts I've heard it's quite robust.

ASF said:

Prosoft make some decent gear too. You will need to sit down before you open the quote, and as FireJo and mk42 describe above it's not your standard WiFi, so you need a sender and a receiver with the receiver hooked into your plant network. But from all accounts I've heard it's quite robust.

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I've used the Prosoft stuff before with a ControlLogix and it works fine as long as you aren't sending to much data. If you try to push too much data you start to have dropouts.

mk42 said:

However, a word of caution: 900MHz solutions are wireless in the sense that they don't have wires, but they aren't "wifi" like your computer/phone would be able to communicate with. They might still work, if you aren't planning on connecting wirelessly with your laptop.

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Mk42 makes a good point. The FLC910E’s aren’t WiFi so you can’t connect to them with anything other than an FLC910E. However they are as fast as 802.11g devices, they take advantage of the higher level of reliability and range that you get with 900MHz over 2.4GHz and they are several magnitudes higher when it comes to RF output power than typical WiFi devices. As to not being WiFi, that has another significant advantage which is security. You can’t hack it if you aren’t using the same frequency band. The FLC910E’s do have encryption but typically it’s not needed.

With regards to wireless in general, one thing to understand is that you are going to lose packets, there simply isn’t any way around it. You will also add latency. The higher the throughput the less latency but you will add some. One of the problems that I find people coming across is they look at wireless Ethernet as Ethernet. In other words they don’t know and/or understand that while the protocol is the same the transportation is different and you have to account for it. For example, connecting Logix PAC’s together EtherNet/IP UDP (Produce/Consume) is usually the best option for a variety of reason not the least of which is you don’t have to program message instructions. However when connecting Logix PAC’s together wirelessly usually the best option, when it comes to reliability, is EtherNet/IP TCP (message instructions). That can sometimes add up to a lot of ladder logic with a lot of message instructions which a lot of programmers don’t like using. In fact I’m coming across more and more guys who don’t know how to create message instructions. Having said that I’m not saying you can’t do Produce/Consume wirelessly but you do have to know what you’re doing and you have to pay attention to the details (amount of data, time intervals, etc…).

Anyway, Jsu0234m you are definitely taking the right approach in researching the best method. You’re going to be much less likely to create an application that doesn’t work as designed.

There is also the option to use the Anybus wireless bridge for Bluetooth. They use 8 channels simutaniously and if one gets disturbance on any channel they will use frequesncy hopping, meaning they are truely disturbance resistant. So, much more reliable than standard wifi...

My 2 cents

In case anyone is interested, there is a whitepaper on wireless technologies available at:
http://www.anybus.com/downloads/Wireless technologies for industrial communication.pdf

Anybus has great support....

10 Analog Pressure transmitters

Resurrecting an old thread.

I am wanting to connect 10 x Pressure sensors to IO-Link and then onto Ethernet/IP to transmit wireless to a compact logic PLC.
Anyone have any ideas of what gear would be reliable in this situation to transmit 10 x analog values back continuously? If I have to I can put a PLC onto the rotating machine to only transmit the data when the heads are in the required position. Machine turns fairly slow at 10RPM for the 10 heads so I would have thought bandwidth shouldn't be an issue. Having said that I would like 200msec update of the pressure for 120deg of the cycle for each head.
Thoughts anyone?

For the gear
Compact Logix
Looking at Balluff Inductive couplers or Deublin electrical slip rings for 24VDC
IFM IO-Link transmitters
IFM IO Link to Ethernet/IP resin filled IP rated bases is where I am currently at