Hello everybody,
I have a research about N-Channel Zegbee to improve its throughput, some study have discussed it
like :
Xing Xu used Micaz and Tole for improvement the throughput with make small center frequency channel.
Xbee have channel mask, which define the channel 11-26 with channel bandwidth 5MHz.
for Example:
channel/mask : 0x7FFF –> 0111 1111 1111 1111 (just 26nd channel isnt active active ).
This tabel describe the channel deatil of zigbee or xbee.
The question:
Can the configuration a on xbee be changed , even though I want to explore the channel on xbee?
i just knew about the configuratin channel xbee, using the bitfield of xbee. May be there is any button that i stiil dont know which need configuration.?
I found this reference
The following table shows four common channel masks, plus one single channel example, to demonstrate how binary bitmasks are linked to individual channels. If there is a 1 in the channel column, that channel is available for use, and will be scanned, when that mask is configured. Remember - it is ONLY the mask in the coordinator which affects the selected channel. Assuming you used fixed PAN Id, then you have the most flexible design by putting the reduced/restricted mask in the coordinator alone, and leaving the other devices to check all channels.
The binary ones and zeros are then converted to hexadecimal to create the mask to configure. Using the last example, forcing channel 25: 0100,0000,0000,0000 in binary is 0x4000 in hexadecimal.
The Question
is node coordinator for Xbee Pro S2C always use channel mask 07FFF for find others end device and avoiding interference with frequency wifi?
It is by default set to 7FFF so that is the channel mask it will use. As indicated it can be changed by you the user.
No, this will not tell it to miss wifi. It does not have the ability to know if the interference it sees is WIFI or something else. When it scans, all it knows is that there is noise on a given channel.
so,
scan channel of Xbee certainly doesnot interfer with wifi?
by the way, i have a question again
i have tried to connect 3 Xbee Pro,
first xbee was used as coordinator node with scan channel “B”
second and third xbee was used as end device node with scan channel “7” (1st Xbee) and “F” (2nd Xbee).
i sent characters on console terminal coordinator to end device, for check the received characters i used “tera term” application.
the result is the characters was received by both of end device, but there is a delay.
i didnt found why it would be like that, can you help me… found the problem?
i thougth the coordinator can connect with end device or router transmit the data without delay.
Let me put it this way. They are two different IEEE standards which use different bandwidths and data rates. So while they may operate on the same frequency, they are not directly completing with each other.
Yes, there is going to be a delay. When using End device configurations, the node is sleeping for a period of time. It needs to wake up first before it can send or receive data. It also most pull its parent router or coordinator for data before it can transmit data.
can i use all of 16 channel alternately for one Xbee ?
for example,
i sent a data1 to channel 11 (sc : 1)
and then
i sent a data2 to channel 12(sc:2)
… etc
If you are working withe the 802.15.4 version of the product, you can enter command mode, change the channel, exit command mode and send data. Then Enter command mode, change the channel, exit command mode and send the data.
thank you for your answer
may i ask question again
in some paper state that the buffer of Zigbee is 127 Byte.
i have tried some Xbee S2, i use ctsPin for this research.
and i found that at least 122 byte that xbee can receive data, but i have read book “Xbee Series 2 OEM RF Modules”. It said that reciever buffer is 34 bytes. (i didnt understand it)
But now, i am trying with xbee pro, i use ctsPin. but the Buffer capacity is more than 36000 bytes,
is that different from xbee and xbee pro especially for s2c type.
Xbee Pro Have higher power that xbee.
one question again,
is Xbee Pro S2C can not connect with Xbee S2C ?
The UART buffer can only hold up to one Modbus packet of 256 bytes in total. With a packet of this size, the RF buffer will transmit this in four 84 byte packets which will provide an over the air packet of 120 bytes each after over head.
All Zigbee enabled modules from Digi have these same limitations.
Modbus is a protocol used in industrial automation. The Zigbee standard is designed to work with this protocol by sending the max modbus packet of 256 bytes in three RF packets over the air and then re-assemble them on the UART of the receiving module.
i have a problem…
i try to make some experience with changing alternate scan channel of node coordinator.
but, sometime i find some a problem which sometime i can not connect coordinator and end device, i tried to find the problem, but i still didnt know “Why”.
i just have checked the PAND ID, the “Scan Channel”, but it was still the same…
may be you can help me, for this problem…
why i can not connect the coordinator and end device, but the last try or the last experience i connect them, and both of them can connect well.
The Operating channel is just that. The channel in which the module is operating on. Where by the Scan Channel is a Channel Mask that the radio can scan and try to find the coordinator operating on and form a network on.
When changing channels or channel masks on the Coordinator, you must make the same changes or corresponding changes on the end device or router.
You need to be careful not the set your coordinator on a channel in which the end device or a lower power module does not support or they will not be able to communicate.
the same channel means operating channel, right?
let me clarify it
operating channel is like channel they can communicate each others, whereas scan channel for connect to coordinator