help in wireless profinet.

good day. in our project it is required to make shuttle conveyor which should move 40 m. there are 3 motor and sensors on it and we want only pull electrical cable for motor drivers. communication between plc on conveyor and another plc (or io) should be wireless using profinet. devices it is better be Vipa or Beckhoff. Please give me advice how to do and what i should use for doing this project. I have little experience and never used wireless communication.
Thanks for help in advance.

abbastukanov said:

good day. in our project it is required to make shuttle conveyor which should move 40 m. there are 3 motor and sensors on it and we want only pull electrical cable for motor drivers. communication between plc on conveyor and another plc (or io) should be wireless using profinet. devices it is better be Vipa or Beckhoff. Please give me advice how to do and what i should use for doing this project. I have little experience and never used wireless communication.
Thanks for help in advance.

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First, I would never recommend using wireless if wired is possible. Wireless should mainly be used in cases where some of the devices are moving (cranes, monorails, AGVs, etc). The cost of a reliable, quality wireless installation is almost always higher than the cost of running a few cables.

Things like interference from other wireless networks, cell phones, microwaves, bluetooth can block wireless communication. Reflections from metal (multipath) and objects blocking line of sight between the AP and client can cause issues. In addition, even though wireless is getting faster and faster, those fast speeds require the clients to be very close (3-6m) to the AP. Realistically, the update times won't be nearly as fast as a wired network.

If you're set on doing wireless Profinet, I'd strongly recommend using wireless Access Points and clients from Siemens that support iPCF. It allows fixed PN update rates, and prevents one client from hogging all the bandwidth, as well as roaming between APs.. It also supports Profisafe devices over profinet.

If there is a fixed path for the movement then I strongly recommend this:

https://www.youtube.com/watch?v=avj-sHHfBYI

We used in the past with great success.

If there is no fixed path then you can certainly use Scalance WiFi equipment, but you have to order a C-Plug to enable Profinet capability.

All the above are not cheap, as Wireless profinet requires special equipment.

If you want something cheaper you can use cheap WiFi gear like Ubiquity and Mikrotik but then you should not try to pass Profinet through them. You can use PLCs at both sides and then utilise PLC-PLC communication.

I guess there are quite a few options depending on:
-Mechanical design
-Speed and RT IO requirement
-Environment
-Amount of data to be transferred

Wireless is ok if the equipment is selected and installed appropriately.

Regards

Nik

For 40 meters i doubt that there is a need for roaming then you could use a product like the WLAN EPA. It is a wireless module and antenna all in one. It can work as a wlan client or in a bridge mode so that you can use 2 antennas to make a wireless bridge and it supports Profinet and Profisafe.

https://www.phoenixcontact.com/online/portal/us?uri=pxc-oc-itemdetail:pid=2700488

https://www.anybus.com/products/wireless-index/anybus-wireless-bridge

If roaming needed then i agree with the rest use Siemens and IPCF

Wireless ProfiNet is a difficult task out of the gate, doing it on a moving piece of equipment adds another level of complexity all together. The first thing I would look at is using something other than ProfiNet. It has latency requirements that are very tight and reliable communications are a must. You can get reliable wireless communications but it’s at the sacrifice of speed. You can get high speed wireless but at the sacrifice of reliability. This is changing but it’s nowhere near what it would take to do ProfiNet wirelessly. There is one exception to that and that is Siemens wireless high speed modems. They were designed to deal with ProfiNet but they are very expensive. It’s been a few years since I’ve worked with any but back when I did they weren’t “mobile friendly”. If cost isn’t an issue I would recommend contacting Siemens and see what they have to say about your application.
What I would recommend, if it’s possible to do, is have two PLC’s on either end using a solid stable communications protocol (Modbus/TCP, EtherNet/IP TCP, etc…) that doesn’t focus on speed but rather reliability. This would give you the ability to use a slower but much more reliable wireless link. You will also be able to have some local (at the shuttle) intelligence that can be useful.

mk42 said:

First, I would never recommend using wireless if wired is possible. Wireless should mainly be used in cases where some of the devices are moving (cranes, monorails, AGVs, etc). The cost of a reliable, quality wireless installation is almost always higher than the cost of running a few cables.

Things like interference from other wireless networks, cell phones, microwaves, bluetooth can block wireless communication. Reflections from metal (multipath) and objects blocking line of sight between the AP and client can cause issues. In addition, even though wireless is getting faster and faster, those fast speeds require the clients to be very close (3-6m) to the AP. Realistically, the update times won't be nearly as fast as a wired network.

Click to expand...

I can’t agree with this. Yes reliable wireless communications can be expensive but it is almost always less expensive than running communication cables correctly (I.E. conduits, junction boxes, etc…). If you are dealing with low cost WiFi equipment then yes it can be difficult to get a reliable link. However low cost WiFi is not the only option out there. Having said that, there are a lot of industrial environments where the 2.4GHz spectrum (where WiFi resides) is very crowded with some so full that you can’t use any more 2.4GHz devices but that is not the norm and if you have someone who knows what they are doing you can usually make it work. The other way to go is 900MHz Frequency Hopping. If you use high quality modems it’s almost impossible to interfere with them and their need for line of sight is much less than 2.4GHz.
The long and short is that if done properly you can do communications wirelessly with a high degree of reliability and can be done at a lower cost than running wires (I’ve been doing it for 20 years).

Thank you for answers. Because of price of siemens i decided do it with anybus wireless bridge. it also supprts profinet. Will i success? I know nothing about communication what is difference between communication with accespoint-client and wireless bridge?
https://www.anybus.com/products/wireless-index/anybus-wireless-bridge

Simple explanation. Normal wifi you have accesspoint(s) and one or several clients that connect to the access points. So theoretically you have one accesspoint on the floor and one client on each shuttle that connect to the accesspoint

The WLAN EPA and Anybus has a special mode that allows to clients to connect to each other to form a wireless bridge (Cable replacement mode). They also have another special mode that normal clients lack except Siemens and a few more that prioritize Profinet. But if you have 2 shuttles you need 4 devices.