Bridge and Bolt communication issues at 50 ft

[amromahayni]

Hi there
I’m having problem with communication dropping with the below units and configurations. Please provide your advice

1. I’m using Anybus bridge II to communicate with 2 No Anybus Bolts. The Bridge is fixed and the 2 No Bolts are movable
2. The coverage distance is for 90 meters (no curves - straight line) and the Bridge is installed in the middle distance at ~ 45 meters.
3. The installation of the 3 units are on line
4. The operating mode of the bridge for the “Easy Config Mode” is done on mode “5” “WLAN AP”
5. The operating mode of bolts for the “Easy Config Mode” is done on mode “4” “Client”
6. The configuration of bridge and bolts are on are on 2.4 GHz & 5 GHz for the Channel Bands
7. The firmware version has been updated from 1.1.6 to 1.3.8 for the bridge and bolts

Please advice what can be done to have proper communication without dropoff
Regards
Amr

[support]

Hello,

We had spoken on the phone earlier I believe. Please let me know if changing the wireless channel helped.

Also, I have requested more information from colleague. I will let you know what they say.

[support]

Do you have another Anybus bridge II you can try?

[amromahayni]

Hi Nick

No I don’t have.
We config the bridge to channel 7 that is not used in our company network. We are still suffering from communication droping and simetimes the bolts required power recycle to run. As per the specs, the bridge is of a range of 400 m and the bolt is upto 100 m. Our maximum range the bolts can go far is 50 m !!! Which is within the range limitations of your system. Wondering why this is happening.

For testing the wifi strength we’ve run an app (can be found online), the strength is dropping to around 50% at the end of the track !!! why do you think this is happening

I attached screen shots for the bridge, for the bolts i was not able
Kindly require to have your advice.
Is there any booster that can be used to increase signal strength
Regards
Amr

[amromahayni]

Attached is picture of the bridge module from inside

[support]

Thank you for the picture, can you try to disable Bluetooth on the Bluetooth tab and see if it helps?

[support]

Hello,

After receiving more information from my colleague we do not think the antenna is broken. Here is some feedback from my colleague,

" channel 7 is overlapping with 11, he should change it to 6 instead, it is only 1, 6 and 11 that should be used in 2.4GHz"

Can you please try 6?

[amromahayni]

Hi Nick
Channel 6 is used in our plant.
Can you give us the all the channel posibillities that we can run on for 2.4GHz and/or 5GHz. Or is there other recommendations
Thx

[support]

Is channel 11 also used?

[amromahayni]

yes used. and channel 1 is also used

[support]

So are all 3 of those channels heavily used? Have you reviewed all three channels with that Wi-Fi scanner software? It seems that if the channels are used but not fully loaded with traffic then they should still work.

If you do not have much 5 GHz usage in the network I think changing the access point to 5Ghz and choosing any channel would work fine.

[kent_hms]

There is a lot of confusion regarding channel usage especially in the 2.4GHz band of WLAN, the channels are 5MHz apart from each other, but each channel uses 20/22MHz bandwidth depending on modulation.
In the below example you can see 2 SSID:s using ch1, 1 using ch3, 2 using ch6 and 3 using ch11. In this setup 1, 3 and 6 will have a very bad performance with a lot of resends due to bad packages, channel 11 though should be ok.

But by changing the SSID on ch3 to either 1, 6 or 11 the problem would be gone. During normal usage the data usage in a network comes in bursts, when you open or save a file to a server or browsing the web, it is only when downloading very big files or streaming video in a high quality that the bandwidth is being used.

My point, the channels are not occupied that much in normal conditions, and as the WLAN is checking if the channel is occupied before sending the data, multiple SSID:s can share the same channel.
More info on CSMA/CA - https://en.wikipedia.org/wiki/Carrier-sense_multiple_access_with_collision_avoidance
There are numerous good sources of information regarding channel usage and other best practice example, a good one can be found at https://www.metageek.com/training/resources/why-channels-1-6-11.html they also manufacture the WiSpy spectrum analyzer that is needed for anyone working with WLAN:s to detect disturbances that are not originating from other WLAN:s but different RF sources (Motion detectors, Industrial remote control, Microwave ovens and so on)

[amromahayni]

Hi Kent
Thanks for your email and explanation
Please find attached the wifi scnning using the software you suggested. Please give advice according to what you see.

I configured the bridge and the 2 bolts on bluetooth and it looks the com is fine but we need to monitor on a longer period to see if any dropping happening.

regards
Amr

[kent_hms]

Hi Amr,

Bluetooth is a good choice if you don’t need high throughput, as it uses a very narrow bandwidth and jumping frequencies it will “always” find it’s way through.
Looking at your RF environment I would recommend changing the two SSID:s on channel 9 to either 1, 6 or 11 as they are now disturbing both channel 6 and 11. The printer using channel 10 (HP075B80) check if they are actually using the WLAN on it, if not, disable it. Check that regarding the other printers as well, if it’s not being used it should be disabled.
In the current setup, the only usable 2.4GHz channel is actually number 1.
In the 5GHz area, we only allow channel 36, 40, 44 and 48 in Access Point mode, and both 36 and 44 are available in your environment, so this is also an option.

All in all, a small cleanup in the 2.4GHz would improve the WLAN for your company, so it will be well worth doing it.

Glad that you found the explanation helpful!

[amromahayni]

Hi Kent

Thanks a lot for the details give … valuable
I will work with IT on your recommendation and see where we can reach

Regarding the bluetooth, we get a total of 128 I/O’s of data (all are discrete) going back and forth. They are not all used at the same time but I need to make further studies on their frequency, if required. Do you think that this much of data is considered high throughput and do you recommed to keep on bluetooth even if the wifi improved or your first option is wifi ??

Thanks once again

Regards
Amr

[kent_hms]

Hi,

What is connected to the different Anybus Wireless devices?
One PLC at the Bridge and I/O nodes at the bolts?
What protocol?
If Ethernet/IP have you changed the RPI (Requested Packet Interval) setting for the I/O devices, should be >64ms.

Bluetooth is best if the throughput is enough as it adapts to the environment.
WLAN is changing, a new printer is installed or a rogue router, so all of a sudden the WLAN can stop working, then you need to do an analysis of the new RF environment and correct it once again.

At least this is true regarding the 2.4GHz band, 5GHz is much better, the channels are positioned so they don’t overlap in normal circumstances.

But we do recommend Bluetooth if robustness is prioritized.

[amromahayni]

Hi Kent

One master scanner (1747-SN) connected to 4 RIO’s, the bolts are 2 of them. There is a converter (AN-X2 from prosoft technology) from DHRIO network to Ethernet to connect to the bolts through ethernet.

Is there any booster or repeater for the bluetooth that can be used ??

I got another question, What do you think the acceptable cycle time for capturing the data without delay ??

Regards
Amr

[kent_hms]

Hi,

We don’t have any booster or repeaters, and I would not recommend the use of it if you were to find one. WLAN and Bluetooth are half-duplex, so adding a repeater will double the response time in any wireless connection, and you don’t want to do that.

I referred to RPI before that it should be set to >64ms, and I’d say the same regarding the cycle time, in Bluetooth I would suggest around 100ms.
If you have many resends and timeouts you need to increase these values.

[amromahayni]

Hi Kent

Thanks for the reply and infromation. It is actually guiding us where to go

I don’t remember if I said before, I mounted the birdge/bolts on the machine and connect to an external PLC. I’ve also programmed closed loop function for testing purpose, sending a discrete output signal and recording the counts on the feedback input signal with an RPI of 100ms. The counts looks quite good.

We are going to try to function it with live machine by next Thursday. Hopefully it run smoothly.
I will let know about the results definitly.

Regards
Amr

[amromahayni]

Hi Kent

Good day !!

Unfortunatly the testing did not go through. We faced problems of data transmission not fast enough eventhough the Status Indication Lights are steady green.

We have total of 160 I/O’s (correction of what I said before 128 I/O’s). Partial of these I/O’s are encoder values send as discrete input and Hydraulic proportional valve send as discrete output. Those values must have correct readings all the time as position and speed need to be controlled.

What can we do to improve. apprecaite your feedback

Regards
Amr