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XBP09-DPSIT-156 vs XBP9B-DPST-001throughput

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Hi,

I have a design based on the XBEE-900-Pro (XBP09-DPSIT-156). I am trying to migrate to the new 900 HP series(XBP9B-DPST-001).
In my m2m application the radios are configured as none-router end nodes at both ends. I have noticed that in this configuration the data throughput with the new 900 HP module is significantly less than that of the Pro module. In this case, streaming rate of 50Hz has dropped to less than 10Hz - with the same packet size .

The numbers in the datasheet also seem to reflect this matter (156kbps for 900Pro vs 10kbps for 900 HP). I was wondering if this information is correct? Also if there is a way to tweak the modules to have the same throughput as the 900Pro versions. Lastly, I would appreciate if anyone knows when does the projected life for the 900 Pro modules end?

cheers
asked Jun 2, 2015 in Interface/Development Boards by msna New to the Community (2 points)

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1 Answer

+1 vote
Try using the DM Code instead of the Point to point 10K Code. You should then see an increase in throughput (DM code can be configured in a Point to point/multi-point configuration at a much higher data rate).

While there has not been an EOL listed for the XBee PRO 900, No new development is occurring and is likely to occur on it. Instead, all new projects should be using the XBee PRO 900 HP.
answered Jun 9, 2015 by mvut Veteran of the Digi Community (13,104 points)
Hi

Thank you for your response. I have loaded the DM software on the radios and it does indeed increase the throughput. Although, now I am facing a rather peculiar issue. I have 2 DP modules (900 HP DPST-001) and 2 DM modules (900 HP DMST -0012). I have loaded all with the DM software. All radios are the S3B edition. One of the DPs is the reciever and the other DP and the 2 DMs are transmitters - not transmitting at the same time of course. All of the radios have the latest DM software installed and the transmitters have the exact settings - I have saved and loaded the same profile. With this setup, the DPST module seems so have a much better throughput than the DMST. If i increase the unicast retries on the DMST modules they improve but still about 30% loss compares to the DPST. I was under the impression that that the DMST and DPST share the same hardware and they are only loaded with a different software. Is this not the case? Can you think of anything that could cause such behaviour? in summary, I am using exactly the same interface to talk to the radios and they are streamed one at a time. The DMST transfers 50 packets/per second even with the unicast retries set to 0. but the DMST modules only transmit about 27 packet/second with the retries set to 0. increasing the retries to 0xA improves the rate to around 38 packets/second which is still about 24% loss.

Thank you
That is correct. They are the exact same hardware and the only difference is the firmware that is installed.  

I am not sure how to answer that.  If you swap where the modules are located, does the issue follow the module or the location?

How about if you swap the antennas, does the issue follow the radio or the antenna?
Hi
Thanks again for your response. At this point I am trying to decide whether to switch to the new HP modules or keep the 900Ps. Thus, i'm testing all of the units in my office. I effectively just un-mount one radio and switch it with the other and do the tests. So they have the exact same location, antenna and hardware talking to them. But as I mentioned earlier i see a different rate between the DPST and DMST radios although both programmed with the DM firmware. I have ordered another DPST unit to verify this. I'll let you know if this is true for the new DPST as well.

cheers,
As Surprising as it sounds, the new DPST module does indeed behave similar to the old one. So maybe there is a hardware difference after all? When I look closely at the modules, the DMST ones have a darker solder mask compared to the DPST ones... I cannot get my head around the different throughput. In the datasheet the DPST and DMST have different receive dBm ratings but i thought that is software dependent. Maybe it is hardware?
The two products are calibrated differently at the factory for maximum output and the different data rates.  I suspect that is the difference and why you see a difference in the range.  Otherwise they are identical.
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