More Xbee latency issues

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jimthree
 
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More Xbee latency issues

Post by jimthree »

Hey Folks,

I know this seems to be a common thread, but I'm wondering if some one can point me in the direction of the current thinking behind getting low latency out of xbee modems.

I have two series 2 xbee's (flashed to the ZB firmware). One is connected to the PC and the other to an Arduino. The Arduino pushes out one byte every 1/10 second, and I watch what is happening on a terminal program on the PC. The Xbees are in transparent mode.

I see a bunch of the bytes come through then a long pause, then a bunch more, then a pause....

I've taken the packetization value down to 0, and i'm running at 9600,8N1 with no flow control. Can anyone suggest any settings that could help get a more consistent and smooth transfer rate?

cheers
Jim

adafruit
 
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Re: More Xbee latency issues

Post by adafruit »

ive not used the series 2 but series one i have latency of about 5ms (measured with my digital scope :) )

r3yzor
 
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Re: More Xbee latency issues

Post by r3yzor »

I've been having the exact same problem. The messages seem to get queued and then are sent out in bursts. then there's a long pause (a few seconds) then another burst of data.

I've tried everything and nothing seems to work. The only way the two seem to talk is if I put one of them in broadcast mode, which might explain the delay, but I haven't been able to confirm that with anyone else.

If you figure it out, please post.

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jimthree
 
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Re: More Xbee latency issues

Post by jimthree »

Hi r3yzor,

I think I've got it working, but testing has come to a halt as I've blown up the regulator on one of my adapter boards!

I found that I was suffering from two different issues. Firstly, I think i may have had a power supply issue. I was powering the Xbee, along with a couple of servos from the Arduino's +5ve Pin. Make sure you have the xbee on a stable dedicated power supply.

Secondly, I explicitly set the source and destination addresses on both the coordinator and router/end device. This works for me because in my application i'm only ever going to have two modems talking to each other. As someone else pointed out, it does kind of defy the point of mesh networking!

cheers
jim

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Re: More Xbee latency issues

Post by adafruit »

mesh networking is really overrated, i think. i use series 1 in direct/point-multipoint mode and they are always working well

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