XBee-PRO 900 Sample Rate Issue

I am trying to take analog data from an outside source and read it in a windows application that I programmed using Visual Studio C#. I originally used a XBee PRO S2 but was unhappy with the 1.2v max input on the pins on the transmitting radio. I then switched to the XBee PRO 900 for its much higher input voltage capacity. I am wanting to live stream analog data from a load cell directly to a graph on my Windows application. To do this, I need a very high sample rate. With the S2, the sample rate could be as fast as 32ms. The issue that I’m having now is that the sample rate on the new radio, even though its set as low as 1ms, is extremely slow. I am using the XCTU software at the time being to troubleshoot this issue. When I change the input voltage, the value doesn’t change on screen for quite some time, as if all the data is flowing into a buffer and then outputting at a later time. This isn’t possible on the serial port side though, because in my Windows application I am streaming the number of bytes currently in the buffer and it is always 0. I have the baud rate of the serial port and XBee set to 230400. To clarify, I did not have this issue when using the S2s. Everything worked exactly as I wanted it to, I just needed a higher input voltage range.

Hardware on transmitting side: XBee-PRO 900 (API mode), XBee breakout board, breadboard, load cell/potentiometer, battery supplying 3.3v.

On the receiving side: XBee-PRO 900 (API mode), Parallax USB adapter board, mini USB cable, computer running WIndows 7.

Any help on what’s causing the slow output rate?


Have you configured the radios for Unicast addressing in a Point to point connection (Non mesh)?

Yes, they are in a non mesh configuration.

What is the Option bit in your TX request frame set to?

There is no TX request, it is a direct data sample.

There is still the CO command which sets the option bit and tells the transmission on what kind of packet it is going to be. That is to say if it is going to be sending it as a Mesh, point to point or repeater. All of this effects the throughput capable by the RF module.

Forgive me if I’m missing something obvious here… but there is no CO command on the firmware I’m using (XBP09-DP, 1067). There is a CE command in the network settings, and that’s the closest setting to what you’re describing.

On that version of the code it is TO instead.