Anybus Wireless Bridge 2 - Multiple Systems / Communication Isolation

Hi,

I am considering using the Anybus Wireless Bridge 2 in a new product line. We conceivably could have 15 products in the same factory next to each other in a grid type fashion. We would be using the bluetooth mode for reliable connection. Each “product” should have it’s own dedicated communication path - i.e no “product” should talk to each other or have any radio interference.

I am concerned with having all these radios in the same area. Should I expect radio interference or is there enough “channels” available in bluetooth? Has Anybus support tried reaching a “limit” of how many radios can be in the same area before communication issues occured?

Thanks,

Linkm

Hello @linkm ,

With bluetooth it is not really that simple. the AWB devices use Bluetooth classic which uses Channel hopping, changing its channel 1600 per second with 37 channels to switch between. The devices [aired sync and jump to the same frequencies at the same time. Over all i dont think the channels are what you would want to look at but rather the though put of blue tooth. The bolts are capable of a maximum best case of 1Mbps. As you add more devices and interference this will go down. I came across this doc when trying to find some details on max devices in a bluetooth area. Microsoft Word - Wi-Fi and Bluetooth - Interference Issues - Rev1.doc (hp.com)

I’ll note that Wifi offers better over all data rates and spreading the devices across the 3 primary channels might give you better results then Bluetooth.

Deryck

Hi Deryck,

I am using this in a PLC application and bluetooth has been proved to be a more reliable signal. Even though the speed isn’t the fastest, it is the most reliable. Here is a sketch for reference.

Each setup is using identical IP Addresses but aren’t connected in anyway. My concern is cross talk between all the different anybus adapters. Will there be any? What’s my limits?

You can reference one of my previous threads here “Best Practices” Best Practices

Hello @linkm,

You should be fine in regards to crosstalk Bluetooth devices jump channels to avoid this and skip ones it finds are busy. I haven’t been able to find any particular info in regards to the limit of devices in one area on Bluetooth. I do not think the number of devices would be the issue here. Your concern would be how busy the spectrum is that would limit how much that Bluetooth could use.

Deryck

When you say my concern should be how busy the spectrum is, what do you mean exactly? I’m interpreting it as if the bluetooth has 63 “channels” available in its spectrum and 40 are already busy from other devices (phones, headsets, etc) and there might be only 23 left for my bluetooth devices to hop around?

Any issues with my setups (from previous chat) having identical IP addresses? Once the anybus wireless 2 units are programed to link - they won’t want to link to other anybus units because the IP address is identical on other setups?

Any other concerns I might have with installing multiple series of anybus wireless 2 setups in one area or building?

Bluetooth uses the 2.4 Ghz spectrum this is an unlicensed spectrum used by other devices and protocols such as Wifi. A channel is a defined range of the spectrum that the protocol(ie wifi, Bluetooth,zigbee) uses. Wifi connections use specific channels and stay on that channel. While Bluetooth breaks up the spectrum more and jumps between channels.

I am not sure I would be able to say for sure if you would have issues with that many devices. I don’t think you would but it is a complicated system and depends on environmental factors.

The Connections made between paired Bluetooth devices are closed connections the IP of one connect will not effect the other.