[Rxtx] Latency Woes

[Jim Redman]

How long does it take the device to generate a response?

Increasing the baud rate may not help you much if the device takes a 
significant amount of time to process the request.


On 03/08/2011 04:26 PM, Curtis Hacker wrote:
> So if I could get the baud up
> 15625, theoretical maximum latency is 1.92ms ? Basically 500 samples/sec ?
> 125000, theoretical maximum latency is 0.24ms ? Basically 4167 samples/sec ?
>
> Keeping the protocol the same.
>
> On 03/08/11 15:05, jfh at greenhousepc.com wrote:
>> Curtis,
>>
>> It's nowhere near that bad.  I'd measured it once before, and I
>> believe it's sub-millisecond.
>> --
>> Julie Haugh
>> Senior Design Engineer
>> greenHouse Computers, LLC // jfh at greenhousepc.com
>> <http://greenhousepc.com> // greenHousePC on Skype
>>
>>
>>     -------- Original Message --------
>>     Subject: Re: [Rxtx] Latency Woes
>>     From: Curtis Hacker <hakcenter at gmail.com <mailto:hakcenter at gmail.com>>
>>     Date: Tue, March 08, 2011 3:27 pm
>>     To: rxtx at qbang.org <mailto:rxtx at qbang.org>
>>
>>     Thank you guys, cause I was really worried there. I guess another win
>>     for math today hahaha. So what is the imposed latency that rxtx has ?
>>     maybe 5-10ms ?
>>
>>     On 03/08/11 13:14, Bob Jacobsen wrote:
>>     > On Mar 8, 2011, at 12:33 PM, Curtis Hacker wrote:
>>     >> Tunerpro log : http://www.ds-map.net/tunerpro_log.csv
>>     > It's only reading one sensor per line.
>>     >
>>     > Note that e.g. Boost PSI changed in lines 6, 30 and 54; every 24
>>     lines. IAT changed in lines 16 and 40; every 24 lines but at a
>>     different phase. GramsRev in lines 23 and 47; every 24 lines, at
>>     yet another phase.
>>     >
>>     > Looks like (69-1) readings in 1.30 seconds = 19msec per reading.
>>     Arithmetic still works!
>>     >
>>     > Bob
>>     > --
>>     > Bob Jacobsen, LBNL
>>     > Bob_Jacobsen at lbl.gov <mailto:Bob_Jacobsen at lbl.gov>
>>     +1-510-486-7355 fax +1-510-643-8497 AIM, Skype JacobsenRG
>>     >
>>     >
>>     >
>>     >
>>     >
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-- 
Jim Redman
(505) 662 5156 x85
http://www.ergotech.com