SCN5 / SCN6 Hardware Thread

[sirnoname]

Any other comments or suggestions ?

Yes, use the shown 3-10-100 timing setup!
The response means that there is a communication problem with one zero leading because of timing problems.
It does not look bad but the leading zero is a problem.

[mereni]

Settings 3,10,100 unfortunately made no difference.

It seems that I always get a reflection of the input msg before getting the reply => input = 16 bytes, reply = 32 bytes !



If event gets worse when I reset the debug mode to zero, the U0p0... reply message seems in that case to be completely garbled and truncated :




What directions do you recommend I should now investigate to try and get rid of that reflection : hardware or software ? (my cables are now so short that, in theory, I can't have electrical reflections at 9600bps, and I should not even need the 120 ohms resistor !) - or do I wait until I get my USConverters' ?

[sirnoname]

do you use 1m cable?

[mereni]

Yes, 1 meter.

[mereni]

I have been thinking further about reflections : with a cable length of 1 m, it would bounce in less than 3 ns, time during which the RD should still be disabled.

I have been trying to find similar cases on the Internet : the transmitter receiving back a copy of what it has emitted.

The first thing I found this : http://tech.groups.yahoo.com/group/ts-7000/message/21336

I then digged a little further into the FT232R chip of Elektor's converter, and I found this :



Could it be the case with this converter here ?

If so, I have difficulties imagining myself implementing the hardware solution : scratching the printed circuit, catching the TDXDEN and Receive signals and putting that back into the RXD pin !!! The remaining solution is software, but how do I tell "the application software to remove the transmitted data from the received data stream" ??

[sirnoname]

No Loopback (echo) is allowed.
If you disconnect all parts from the adapter output (RS485), you go into a terminal program like "putty" and you press a key like "A", this A shall not be returned by a adapter loopback.
If the SP481 has an internal loopback then this IC is not possible.

[mereni]

I have run the test you recommended, and yes, there is definitly a loop-back in place in these converters : all cables disconnected, I get a reply perfectly identical to the original message.

No real success at this point, but at least I now know why they do not work, and I have learnt a lot in the meanwhile.

Since there is apparently nothing else I can do from the HW or SW standpoints, I'll have to wait until I get the adaptors from USConverters (beginning of next year). Thank you very much for your assistance ; I'll keep you posted of my progress with the new ones...

[mereni]

Hi

Excellent news : I have received today my "Professional" USB to RS485 from US Converters today, and they work perfectly. This confirms that the Elektor converters indeed did not work because of their built-in (and undocumented !) loop-back feature.

As a result, I have now almost completed my XP to Windows 7 migration. The only remaining bad news is that I am now trying to launch (for the first time) the X-Sim 3 Extractor, and I am getting a message which has been mentionned elsewhere in the forums :



As you can guess, I do not use a proxy, so I can't fix that ! I consequently guess I will have to use the offline version. If I understand well, this requires a key.

In my mind, my project is too complicated and costly to deserve a Project Page, but I obviously have no objection to a donation, on the opposite. In that case, what is the exactly the process and how much does it cost ?

[prodigy]

As you can guess, I do not use a proxy, so I can't fix that ! I consequently guess I will have to use the offline version. If I understand well, this requires a key.

In my mind, my project is too complicated and costly to deserve a Project Page, but I obviously have no objection to a donation, on the opposite. In that case, what is the exactly the process and how much does it cost ?

The X-Sim servers are probably only temporarily down for maintenance, whey they're will be online, you will be able to start free version of X-Sim.

If you want to buy offline version, there is "Supporter Edition" of X-Sim when you donate min. 30 Euros.
Check more HERE

[mereni]

Donation done right away !

Keep up the excellent job !