Hi, guys.
I have a few questions about XBP modules. What type should I chose for connection between two STM8 microcontrollers? In my city I can buy
XBP24BZ7SITB003 and XBP24BZ7SIT-004 for long distance application.
I understand, that difference is in microcontroller. Shall I need to program it?
I don’t have an experience with wireless networking. So, as I understand, modules on default configured as routers. Will they work as router-to-router? Or firstly I will need to buy an interface board? In my city available DVB ZEGBEE XBIB-R/U. I’ve read datasheet “XBee®/XBee-PRO® ZB RF Modules” and understand, that this modules “transparent” for UART applications. So, couple suggestion will be helpful.
One more. What communication distance I can reach on a straight line in “metal pipe” with 10 meters diameter? What about directive antennas?
Yours is the kind of question that has to be answered with more questions
The first question is: what range do you actually need? If nodes in your network are far enough apart to need routers between them, then you do need either Digimesh modules (based on series 1 hardware) or Zigbee modules (series 2 hardware). The Zigbee modules are what you say are available to you.
If the range is such that all modules in the network can directly transmit to each other, then you can look at the 802.15.4 modules (series 1 hardware). Their big advantage is that they’re much easier to use. I understand they’re not locally available; is it possible for you to buy online?
Another question: will you be wanting to attach sensors to the modules, sampling the sensor conditions every so often or under certain conditions and then transmitting the results? If so, there are other differences between the different firmware versions.
You will need a development board, though you can build your own if you prefer. Digi publish their schematics on their site, and you can use that as a guide. Also check out the FAQ (see pinned posts at the top of the forum) - it discusses what connections you need.
As for the metal pipe, I’m afraid I have no idea - perhaps others can chime in. That’s an awfully big pipe! Does it have trains running in it, or what?
Directional antennas are available for some models, though again I’m no expert there.
If you can give us more details about what you’re trying to achieve, it’d be very helpful.
Thanks for the answer, Johnf.
What I’m trying to achieve is:
I need range near 900 meters on a straight line in workshop. That’s why I’m wrote “metal pipe” - it has near 10*10m dimensions and a lot of metalware there. About walls and roof I can say, that they “screen” all frequencies higher then 2GHz (and, therefore reflect them).
I need both-sided transmission rate 1kBs and higher with guaranty of delivery between two points: sensor (with digital base and almost any interface on it’s output) and black box, that “make a decision”.
That is all.
Why I looked on ZigBee standart at 2.4 GHz? Couple of reasons.
First off all there is a lot of electric drives there with total power near 10MW. All they working asynchronously and making a lot of noise in range 1kHz to 160MHz. I can’t use LPD or PMR ranges because they overload in this area. The next thing - in my country license-free mostly powerful range is 2400-2483 MHz (500mW). I choose this XBP24BZ7 because they mostly powerful from all product line with 63mW output power, that purchasable in Ukraine. I’ ve explore some electromagnetic theory issues and found, that there is a big attenuation of signal propagating along metal wall.
That why I’ve asked about directive antennas.
Anyway, like you sad, I want two modules that could directly transmit to each other.
Could I reach this distances with two XBP24BZ7 modules?
I’ve found Robert Falude’s book and a “Cookbook” but while I’ll do this homework I whant to order modules.
In further fault-tolerant applications I’d like to have real nodes, doubling each other, and couple of routers, some-kind of backup of hardware.
But now I steel a dummy in newest radio communication devices, such as 802.15.4.
One remark: XBees on their own will not give you guaranteed delivery of packets. If transmission fails, through interference or other reasons, they will retry several times and then if the retries fail they will give up. So to get guaranteed delivery you need to implement your own end-to-end protocol. Even then, if interference is heavy and sustained, nothing will get through.
As for the rest of the requirements, I’d suggest that you put in a support request to the knowledgeable folks at Digi Support. I reckon your situation is so specialised that they’re the best ones to give advice - certainly in this sort of situation there’s nothing in my experience that would help you. They, on the other hand, have a lot of experience of different kinds of installation. If you refer to this thread, they’ll see that you “did your homework” first
Worstcase you’d need to make use ZB’s mesh/router feature and use 1 or 2 ‘repeaters’ along the 900M length. You certainly will want the external antenna, so XBP24BZ7SIT-004. The other “SITB003” would only be of use if youwanted to use the second freescale HC08 processor on board. The RADIO would be the same power/function on both.
Repeaters are nothing special - they can be nothing more than an Xbee with 3.3vdc power and router firmware. or they could be the same STM8 design.
To minimize interference, you can use high-gain directional “Yagi” antennas or even patch (circular polarization) antennas. Using either of these, you can operate the radio at a lower power and get great performance. I would recommend this style of antenna even with a 2.4GHz radio.
If you have Wi-Fi in the building, you could utilize two of our new Wi-Fi XBees. These would piggyback onto the existing Ethernet network. However, I cannot guarantee they are available in your country since they are newer radios.
Finally, if you do not mind having multiple radios in the building, you could utilize either Digimesh or ZigBee radios. Start with two radios, and if you cannot get the range needed, add additional radios to act as range extenders. Between the two, Digimesh is significantly easier to work with."
