PLC wireless connection >1500m

[DLMUK]

Hi,

I need to get a PLC (S7-1200) located on an installation connected over wireless to a HMI (Siemens Comfort) onshore. The distance is 1500m. Direct line of sight. Area between the two is water so there is no option for repeaters.

Does anybody know of suitable equipment to do this? Looking at some of the Siemens WLAN products they won't go that far, not sure that WLAN in general will go that far.

Any ideas welcomed.

Thanks

 

[OkiePC]

https://www.ubnt.com/

A couple of our customers use their Nanostation and it seems to work well with Rockwell products (Ethernet IP radio).

 

[MichaelG]

Issues with water and long radio links.
Tidal effects and ships breaking the direct line of sight

https://en.wikipedia.org/wiki/Fresnel_zone

Best recommendation is for the directional antenna to be as high as possible

 

[DLMUK]

Thanks all - will take a look

 

[RET]

Another vote for ubiquity products.

 

[Onstege]

I've recently finished a project using Ubiquiti stuff for Modbus TCP and have no complaints...

 

[grnick50]

+1 for the ubiquity but bare in mind that they are not industrial products. Be aware if you need loads of certificates and so on.
I had to work with scalance and I really dont think very highly of them. It is true that their range is limited due to restrictions on their transmission power depending on the country. Ubiquity can give you many km of range but I dont know how the handle local legislation about transmission power. If your radio link is above the sea then you have to consider that too.
Also you need to consider enviromental conditions like sea salt corossion, coated PCBs and so on.

 

[mk42]

I second the comments about environmental conditions (sea salt corrosion, etc) and probably needing the antennas high, due to fresnel zones and the potential for passing ships. The antenna mounting will probably be the most complicated part of the endeavor. I always recommend a site survey to measure existing interference, but I really doubt that will end up being an issue for you.

On the plus side, you shouldn't need anything too fancy on the wireless software side of things. HMI communications are much slower than IO communications, so I would think just about any (reliable) hw should be capable. IO communications typically need guaranteed update times around 10-50 ms, whereas HMIs often default to 1 or 2 s for updates, and are much more forgiving on comm errors.

 

[Firejo]

If this application is going to be anywhere in Europe the problem you’re going to have isn’t finding someone who sells a radio that will work but rather finding one that will go that distance but still be operating within the legal output power limits. The ETSI standard that covers the type of radio modem you’re looking for dictates (among other things) that the maximum transmitter power is 100mW and the maximum E.I.R.P. (power at the antenna) is also only 100mW. With this the maximum range is going to be somewhere around 1000 meters and that’s with 14dBi gain on a directional antenna (at both ends) and the radios power turned down so that the E.I.R.P. is 100mW (if you lower the transmitter power and increase the antenna gain you can maintain 100mW E.I. R.P. but because antenna gain is both transmit and receive you get a higher receiver sensitivity increasing your range).
Having said that, if you use 19dBi gain panel antenna’s and (are able to) turn the transmitter down to 1dB (which most devices won’t do), in ideal conditions you should be able to get 1900 meters but it’s going to be touchy (if the wind blows the antenna off a few degree’s you’ll lose signal).

 

[Saffa]

Engage a radio engineer to craft a licenced channel for you in the UHF band and be done with it. Not sure about there but here the licence fee is only about 255 dollars a year.

The Schneider Trio Q series radios will do ethernet IP on a UHF channel. You haven't specified how much data needs to be sent but you can easily do 4800bps half duplex on a 12.5khz channel at 1500m without trying very hard.