Hello,
I have configured a network of 1 coordinator to 16 end devices in which we have done continuous 3 days network communication testing. In these 3 days data transfer between the coordinator and end device is successful with zero loss and no range issues. The communication was successful even after the coordinator is power off and then on after sometime, still the end devices did not loose the network. After 3 days I had turned the coordinator OFF for some 10mins duration n end devices were on. When I turned on the coordinator back, the end device did not retrieved and loss of communication was found. I left the system as it to observe whether they will get retrieved on their own, and all end devices were back into network one by one after a duration of 6-7hrs.
Since then I started testing in this way of turning off the coordinator and on to check whether same problem is observed again. Then I observed that by performing this test the end devices are loosing network in between and are retrieved again on their own. I am facing same problem on site where there are 6 coordinators installed against each there are 2 end devices. they tend to loose the network and go into communication failure for any unpredictable time duration from 1min to 5-6 hours. Kindly suggest what can lead to such issues and how I can work out to solve them.
The module I am using is S2C XBP24CZ7UIT-004-revD
This is per the Zigbee standard that these modules follow. The Coordinator is intended and designed to be an Always on device.
Any device if it is not able to communicant with its parent after 3 times will go into what is called a soft re-join. If that fails again 3 times will it then go into a full join.
Your fix to the issue is to simply DON’T power off the coordinator. If you are worried about it loosing power for some reason, give it a battery backup that charges the battery when it is plugged in.
The NJ command set in the network I have formed is
Coordinator - 0xFF
Router - 0xFE
End device - 0x01
Can this parameter be the reason for End device to loose the communication?
SP - 82
SN - 3E8
SO - 0
same for all three end device, coordinator and router.
Should I change the value of NJ for end device as it is 1 sec, increasing it can can solve the issue?
Being 1 sec at present it might try to leave the network after searching coordinator for 1 sec in absence of coordinator. I cannot keep NJ value FF for end device and router as it does not leave the network once connected. And when I replace the coordinator in a existing network the end device and router does not get connected though pan id being same for all, its OI value gets fixed.
OK, I have increased it on site and made it 200sec, what is the best NJ value I can keep. Please, suggest.
My instrument network is of 1 coordinator to maximum 25 end device along with 1 router, as 1 coordinator can support only 20 end devices directly by datasheet.So, 1 router has been recommended in network for support and more repeaters can be added for range improvement.This is the maximum qty which can be configured on site but right now smaller qty are being installed as per requirement eg. 1 coordinator to max 8 end devices with router for range improvement is installed on site where this problem is observed. I want to know best value of NJ I can set to support both max and min numbers of end device connected in network.
Kindly provide some guidance on concept of NJ as it is bit confusing.
Below statement in datasheet indicates what?
If NJ < 0xFF, joining will be enabled only for a number of seconds, based on the NJ parameter. The timer is started once the XBee joins a network. Joining will not be re-enabled if the module is power cycled or reset.
To my knowledge I have understood that after joining a network the end device will be connected in the network only for NJsecs?
What after 200secs in my case, will it leave the network after 200secs or it will start the timer again?
And if a end device is turned off then what after turning it ON will timer for NJ be restarted.
Will NJ timer restart after every wake up from sleep mode?
And after preceeding the NJ value will the XBEE go in retry mode.
what happens in retry mode?
Suppose suddenly an end device operating on approx -60dbm leaves the network what it indicates, theoretically it should’nt be doing so but practically it is happening.
What happens on coordinator side after NJ=FFsecs when timer reaches FFsecs what does it do?
I want to know what exactly happens after timer reaches NJsecs, this concept is not cleared by datasheet that what the XBEE module will do after NJsecs.
Because losing network at -60dbm is not acceptable.
the range value is -26 to -88dbm for S2c.
Can XBEE module range go beyond this value and if it goes what can cause it to do so.