# Reading analog signals from Xbees

Hi,

I have started to work with these Xbees, in order to see if they fit on a project that I’m doing. I have just bought a development kit with 2 Serie 1 Xbee Pro, a board to connect one to the computer through USB and another board to connect it through a RS232 cable, from digi. (Actually, they didn’t bring me a board with a RS232 cable, but 2 with usb, and I needed a RS232 so I’m a bit angry with digi D: ). http://es.farnell.com/digi-international/xb24-dks/development-kit-with-xbee-module/dp/1337915#accessories

Let bygones be bygones, I’d like to do my question:
My system will consist of 13 Xbees, each of them sending 80Bytes of information + Addressing every 1.33s (20 measurements of 2 ADC signals, all of them trying to send at the same moment!), to a coordinator Xbee. All of the 13 set with the DH=0x00 and DL=0x01. The coordinator MY=0x01, DH=0x00 and Dl=0xFFFF. I hope that is low data rate for the Xbee to handle. However, my question is regarding the ADC measurements of the Xbee. I’ll be measuring the ADC every 66ms, so, what would happen if the Xbee is trying to send the information (whether it is sending RF, reading the channel air-CSMA/CA, waiting for another Xbee to end comunication…) and the time to do an ADC measurements arrives? Will the Xbee be reading the channel or sending the information and will lose the ADC measurement that should have been done? Will the measurement be done at the same time as the Xbee is waiting to send the previous information, and saved in some kind of buffer for the next group of 20 measurements?

I hope that you understood my question and that you can find an answer.

Thank you very much.

Let me answer it this way. The radio can only perform one function at a time. So if it is already performing one function when a 2nd function is scheduled to occur, that 2nd function can’t occur till the first one is completed.