we were just wondering how many XBees can we connect to one coordinator without getting interfirance or problems,
we have it running fine with 4 Xbees on one coordinator but as soon as we connect a lot more, like more then 15 or so it goes crazy and cant handle it anymore,
even less make a problem, 4 seem to be stable.
do we need to form little subnets of 4-5 xbees end-devices each on a router and then send them to the coordintor from the router?
what is the official maximum of end-devices on one coordinator?
just sending little bits of data, every ten seconds so shouldnt be too much data,
The number of remaining end device children a device can allow can be read by issuing the NC command. In ZB, it is 10 on the coordinator and AT routers, and 12 on API routers.
Once NC=0 and a router/coordinator cannot allow any more joins, additional end devices must be within range of a router/coord that is allowing end devices to join.
The 10-12 child limit is mostly a function of balancing RAM. There is a finite amount of RAM that must be shared among the end device child table, packet buffer space, UART buffers, routing tables, etc. Also, keep in mind that since a router must buffer packets for its end device children, increasing the number of end device children a single router has can require more RAM to buffer packets for the additional children.
dasmeer:
we were just wondering how many XBees can we connect to one coordinator without getting interfirance or problems,
we have it running fine with 4 Xbees on one coordinator but as soon as we connect a lot more, like more then 15 or so it goes crazy and cant handle it anymore,
even less make a problem, 4 seem to be stable.
do we need to form little subnets of 4-5 xbees end-devices each on a router and then send them to the coordintor from the router?
what is the official maximum of end-devices on one coordinator?
just sending little bits of data, every ten seconds so shouldnt be too much data,
Thanks
Heaps,
dasmeer
Sounds like an implementation error to me. You will need an application layer error recovery for lost and duplicate error messages - they are inevitable in wireless.
Check if you have the MAC layer ACK option turned on.
As said earlier, you didn’t say if you are using ZigBee, DigiMesh or simple 802.15.4 mode.
Also, note that you can run XBees in 802.15.4 mode as peer-to-peer and not need to mess with coordinators, associations and all that rot.
I had just a few modules (Xbee ZB) running at had major lag and other problems until I realized that having all modules’ destination address set to broadcast was not a very good idea.
Make sure that all messages are addressed to one specific recipient, and do not use broadcast messages unless absolutely necessary.
Johan Adler:
I had just a few modules (Xbee ZB) running at had major lag and other problems until I realized that having all modules’ destination address set to broadcast was not a very good idea.
Make sure that all messages are addressed to one specific recipient, and do not use broadcast messages unless absolutely necessary.
for this arrangement, you have a star topology. So ZigBee is useless complexity.
May as well use peer to peer 802.15.4 mode, no ZigBee, no coordinator needed. Any node can, if desired, talk to any in-range node. It’s like 802.11 ad-hoc mode using static IPs.