Devantech USB adaptor vs Cheap Ebay adaptor

USING ONE COMPUTER FOR EVERYTHING.


Bought two adaptors from China, cheap £7.00 each. Did 160 outputs per second (drops to 110 when running game)

Bought two Devantech adaptors £15.00 each: Did 220 outputs per second. (drops to 180 when running game)

I recomend Daventech adaptors, especially for people running profiler and sender + game on one computer.

hi could you post the e-bay link ? cheers

http://cgi.ebay.co.uk/USB-RS232-UART-TT ... 3f00b3e368

the devantech company is in the uk. robotic-electronics. type it in google.

I tested almost all of the off the shelf options. Amazingly, they all performed differently, even when they used the same chip. Of the FTDI 232R adapters, the Devantech was the third best performer, just behind FTDI's implementation of the chip: http://www.ftdichip.com/Documents/DataS ... S_v130.pdf and the SX-3000.

Could you share your settings in Profiler for the Devantech rs485 to usb ?

I am getting an average of 160 output/seconds with default Profiler (2.1.0.4) settings of 1-0-100.

Did not try to check LPT in the adapter properties like some users here metionned ...

What is the 'normal' average output/seconds we can get with these adapters?

Also, what should be the initial speed and acceleration values?


Thx!


Bleco

Hi Bleco,

It has been a very long time, and I can't remember what settings I used when I evaluated the Devantech adapters, but I do recall that they achieved 220 theoretical updates/sec. Somewhere in the forums (probably the SCN5 hardware thread, I posted the settings and screenshots of them. For the SX-3000 I wound up customizing the driver and getting it recertified by Microsoft because the default parameter options were not optimal for simulation, which is how I now achieve in excess of 250 updates/sec. on high performance PC's.

Thanks Bernard,

I will search at large ...


Bleco

Never find your post but finally achieve a peak of 210 output/secondes with 0-0-200 settings ... It varies however, most of the time getting 200 output/secondes ... will try other combinations later ...

Bleco

With Devantech i:

Went to device manager to edit com port settings:

I set Latency to 0
And I ticked the Close RTS box.
Bits per second 4096

In the sc5 interface settings I:

0ms

0ms

70ms


And unchecked all 4 boxes. With devantech you should be getting 220 outputs per second atleast.

Some PC's and adapters will run well with 0,0 settings, and others will occasionally drop a conection to an actuator with these settings, which is very frustrating when you're in a race.

@Fahim, you are mistmatching your FTDI and X-Sim timeout values. The lowest default FTDI timeout is 100.

Bernard:

I effectively had issues with one actuator dropping its connection while in game ... What do you suggest ?

I am getting the same response results with 0-1-200 ... minimum of 200 output/sec ... will stick to that for now...


Fahim: Minimum latency value in com port settings is 1 ... how could you set it to 0 ?


Thx!

Bleco

Bernard, what do you mean?

You mean the 70ms? It should be 100ms?

Everything seems to be running fine.

BTW bleco. I've got artificial break time at 12ms in the program setting in profiler software. And 12ms in the force sender polling speed.

I am finally getting 250 output/secondes after tweaking scn5 and com port settings ...

however it doesn't seem to be very consistent ... I can get 250 and then next hardware scan 166 and then 200 and then 250 ... What can explain this ?




Thanks!

Bleco

200ms in the interface?

Is that a good thing?

I have it on 70ms

It is important to understand what these settings actually do.

70ms or 200ms -- doesn't effect your performance. It is a timeout value. It only has an impact when either something in the Windows OS or X-Sim software or FTDI driver goes bad an causes an excessive delay. X-Sim is not known to have this problem, but many factors can cause windows or the driver to have an excessive delay. The example shown in the picture above is not an optimal configuration because the FTDI driver timeout is set to unlimited and the X-Sim timeout is 200ms. In my testing, I have found the best recovery from rare Windows timing issues to be when the FTDI driver and X-Sim timeout settings match. Since the lowest FTDI timeout is 100ms, then the best matching value is 100ms.

Also, the subject of performance gets much more complicated than this. Just because X-Sim says 250 updates a second, does not mean that you are getting these updates to the actuator! You may simply be filling the FTDI buffer at a very fast rate causing X-Sim to think that you are getting a good update rate when in fact you are not.

Setting latency to 0 will only make things worse. It's sort of like overclocking in that some PC's can handle the aggressive timing settings with no problem and others cannot. There is no good explantion for why some PC's can handle aggressive timing and others do not, it's just the luck of the draw. If you have problems with 0,0,100, then try 1,1,100. It is better to have stable consistent performance than to have a high update rate that stops working in the middle of a race.

Hi,

With these settings I am getting constant 200 outputs/sec each time I scan for hardware changes.



I have found out that in my case enabling LPT printer check in com port settings resulted in making very inconsistent results ...

If I set the switching time value to 1, I am getting constant 166 outputs/sec ...

I will do some in game testing to with 0-0-100 settings and if I am having issues with actuators connection drops then I will stick to 1-0-100 ...


Thanks!

Bleco

Please refer to my above post again. Your timeout settings are still mismatched. 0 = unlimited in the advanced virtual com port settings.

I have tested each of these scenarious when developing the SX-3000 under various circumstances including an intentional strain on the OS. This is when the timeout settings become most important.

Hi Bernard,

Thank you again for trying to help me with this ... I wish I could spend more time on this project these days ...

Is it better like that?




Bleco

Yes, this corrects your timeout settings. We'll leave the rest for sometime when I can write a tutorial about how the virtual COM port actually works.