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Scan Channel on Xbee S2C

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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 ).


Decimal Hex Frequency SC mask WiFi Conflict Comments
11 0x0B 2.405GHz 0x0001 Overlaps Ch 1 Newer XBee only
12 0x0C 2.410GHz 0x0002 Overlaps Ch 1
13 0x0D 2.415GHz 0x0004 Overlaps Ch 1
14 0x0E 2.420GHz 0x0008 Overlaps Ch 1
15 0x0F 2.425GHz 0x0010 Overlaps Ch 6
16 0x10 2.430GHz 0x0020 Overlaps Ch 6
17 0x11 2.435GHz 0x0040 Overlaps Ch 6
18 0x12 2.440GHz 0x0080 Overlaps Ch 6
19 0x13 2.445GHz 0x0100 Overlaps Ch 6
20 0x14 2.450GHz 0x0200 Overlaps Ch 11
21 0x15 2.455GHz 0x0400 Overlaps Ch 11
22 0x16 2.460GHz 0x0800 Overlaps Ch 11
23 0x17 2.465GHz 0x1000 Overlaps Ch 11
24 0x18 2.470GHz 0x2000 Overlaps Ch 11 Newer XBee only
25 0x19 2.475GHz 0x4000 No Conflict Newer XBee only
26 0x1A 2.480GHz 0x8000 No Conflict Newer non-PRO XBee only

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.?

Thank you
asked Jul 19, 2017 in RF Solutions and XBee by musayyanah New to the Community (0 points)

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1 Answer

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Sure you can. Just change the CM command on all of your nodes and then issue a Global network reset.
answered Jul 19, 2017 by mvut Veteran of the Digi Community (12,315 points)
I want to ask again about this tabel,

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.


Channel/Mask    Notes    26    25    24    23    22    21    20    19    18    17    16    15    14    13    12    11
0xFFFF    All channels, may get low-power channel 26    1    1    1    1    1    1    1    1    1    1    1    1    1    1    1    1
0x1FFE    Best for mixed old/new Xbee networks, very safe    0    0    0    1    1    1    1    1    1    1    1    1    1    1    1    0
0x3FFF    Newer Digi XBee PRO (S2)    0    0    1    1    1    1    1    1    1    1    1    1    1    1    1    1
0x7FFF    Digi XBee PRO (S2B/S2C)    0    1    1    1    1    1    1    1    1    1    1    1    1    1    1    1
0x4000    Example of single channel (Channel 25 only)



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.
may i ask question again?

in spesification of Xbee,
there are 16 channels

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

i used those channel for one Xbee,
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.

You can't do that in Zigbee or Digi mesh.
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 ?

thank you for your response
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.
what is the mean of Modbus paket?
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.
thank you for your reply, may i ask again about this?

i have senit characters of numbers,
for example
"199"

then, i watch it for receiver side on "console log"
199 would be 199 --- 0A 31 39 39 0D

did you know what is 0A .. 0D?
thank you
That is hex characters. 0D is a <CR>. 0A I believe is a esp character.
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.
may i as question again?
What is different "Scan Channel" and "Opertaing Channel"
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.
hELLO
i'm back again..
can they (refers to 3 device Xbee) communicate each other on different channel?

First Xbee as coordinator create operating channel D
Second Xbee as Router join the network of coordinator, so it means Router use channel D

the third Xbee as end device used other channel which differ with coordinator, can it happen?

i just want to explore multiple channel that can use on Zigbee or Xbee?

Please help me
No, they all need to be on the same channel.
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

am i right?
Yes, they would all need to be on the Same Operating channel. The Scan channel just tells the nodes which channels to find the coordinator on. The SC for the coordinator tells the coordinator which channels it can select from to start the network on.
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