Hello world!!,

I have a EMS system in out plant which is having 8 Slave carriers and 1 master system. Communication between the Slave and master is done using the RCOAX wireless communication system. For better understanding please go through the attached PPTx.

The issue which i am facing is communication delay in 2 carriers out of 8 while the rest of the carriers is ok. The hardware structure, programs and wireless devices are same in all the carriers. We have check the signal strength of all carriers and found it lies between 60-90%.

please tell me the checkpoint which i need to go through.

Hello,
Signal strength is important (and the values you mention are OK), but may other factors can influence the wirteless performance like the presence of other WLAN nearby on the same channel.
The scalance W devices have logs and also WLAN statistics.
In the W788-1RR you could check the log for "overlap AP". If you find some on the same channel as the one you use, try a channel with less interference.
The statistics in the W747clients and the AP W788 will give an idea over the quality of the transmission.
I hope that you also have choosen the right frequency band corresponding to the Rcoax installed.
(there is RCoax for 2,4 Ghz, and Rcoax for 5Ghz band).

I see that the wireless components have RR (rapid roaming) in their denomination.
Means that they all support a feature called iPCF.
But we do not kmow from your explanation if you have activated that feature.
One of the benefits of iPCF is that Clients register very fast at the AP, and that the AP also organizes the traffic to guaranty a fair access to each client.

Finally, we need to know what mechanism is used to communicate between the CPU315 and the IM151-8. May be the problem is in the way this is written.
If the wireless performances are good, I expect delays less than 1 sec between the CPU315 and the IM151-8.

The CPU315 could read over SNMP what the signal strength is for each client.
There is a library as application sample.

Hello there, 

Our wireless system has been configured in 5Ghz and channel 36 and also there are near by wireless system also there some are in 2.4 Ghz and some in 5Ghz but channel 36 is not been using anywhere. For your reference i have attached AP and client configuration files.

I will look into the system buffer of AP and Client regarding the overlap and will confirm you.

Hello,
Because you have only one Access Point AP in your configuration, there is no roaming involved (roaming is jumping from one to a better AP).
Therefore you can avoid clients to look for better APs ==> disable the backgrounds scan at the clients.

In the same way, if the AP sends on channel 36, you could tell the clients only to look at channel 36, by deactivating the other channels in the clients. Be aware that if you later on want to change the channel used by the AP, that you must adapt than the clients accordingly!!.

If the statistics are not good, reducing the baudrate is also worth to try. This is done at the AP by deactivating certain higher speeds.

Anyway, before making changes, please make a backup of the AP and clients.

But as told before, please look at the way the communication is triggered in the PLCs.
Evaluate error codes there also.