We just bought a new device from ANT (TMSI Refa 32 channels amplifier), but for some reason a lot of samples are missing when recording (see attachment). The following warning message is thrown: "dummy values so far..."
The strange thing is, we successfully used openvibe before on a similar amplifier from ANT, but an older one.
Could anyone point me in a direction to quickly solve this problem or does it concern a mismatch between the nexus driver and the new TMSI/ANT amplifier?
ANT TMSI Refa 8
ANT TMSI Refa 8
- Attachments
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- eeg_test_ov.JPG (105.79 KiB) Viewed 16919 times
Re: ANT TMSI Refa 8
Dear ddvlamin,
are you able to test the Nexus Driver with your old ANT amplifier ? Just to check the Nexus Driver is not broken. Also we add some issues with the OS drivers of the Nexus in the past. Maybe you can check that the OS drivers shipped with your new ANT amplifier are the same as those shipped with your old ANT amplifier. In case they are not the same, maybe try to install the older version with the new amplifier...
Tell me about your progress.
Happy new year,
Yann
are you able to test the Nexus Driver with your old ANT amplifier ? Just to check the Nexus Driver is not broken. Also we add some issues with the OS drivers of the Nexus in the past. Maybe you can check that the OS drivers shipped with your new ANT amplifier are the same as those shipped with your old ANT amplifier. In case they are not the same, maybe try to install the older version with the new amplifier...
Tell me about your progress.
Happy new year,
Yann
Re: ANT TMSI Refa 8
are you able to test the Nexus Driver with your old ANT amplifier ?
Yes, with the old amplifier and old drivers there is no problem.
No they are not the same as the old driver does not recognize the amplifier, while the new driver does. The dll files and inf files are also updated.Maybe you can check that the OS drivers shipped with your new ANT amplifier are the same as those shipped with your old ANT amplifier.
This does not work as the acquisition device is not recognized with the old driver.In case they are not the same, maybe try to install the older version with the new amplifier...
What could the possible reason be for the warning message "dummy samples so far...."?
Re: ANT TMSI Refa 8
Dear ddvlamin,
unfortunately, the message about "dummy samples added or removed so far" is reflecting the fact that the acquisition driver is not receiving the correct number of samples from the device in a given amount of time. In such condition, the acquisition server fills the holes when some samples are missing or removes some sample when it receives too much samples. We needed that with our Nexus32 (equivalent of TMSi Porti32) because it sent the samples weirdly sometimes...
Could you please send me a 1mn GDF file recorded with your new amplifier ?
Thank you,
Yann
unfortunately, the message about "dummy samples added or removed so far" is reflecting the fact that the acquisition driver is not receiving the correct number of samples from the device in a given amount of time. In such condition, the acquisition server fills the holes when some samples are missing or removes some sample when it receives too much samples. We needed that with our Nexus32 (equivalent of TMSi Porti32) because it sent the samples weirdly sometimes...
Could you please send me a 1mn GDF file recorded with your new amplifier ?
Thank you,
Yann
Re: ANT TMSI Refa 8
Hereby the requested gdf files.
I saw you are working on an acquisition interface for the Refa system. Is it possible to get the preliminary source of that because I don't seem to find it in the latest svn repo. That way maybe I'm able to work on it myself.
I also looked at the WDM drivers given by TMSI and they use the RTinst.dll to communicate with the acquisition device, which is probably something else than the NexusDLL?
I saw you are working on an acquisition interface for the Refa system. Is it possible to get the preliminary source of that because I don't seem to find it in the latest svn repo. That way maybe I'm able to work on it myself.
I also looked at the WDM drivers given by TMSI and they use the RTinst.dll to communicate with the acquisition device, which is probably something else than the NexusDLL?
- Attachments
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- Refa8_Test2.zip
- (121.08 KiB) Downloaded 307 times
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- refa8_test.zip
- (156.98 KiB) Downloaded 289 times
Re: ANT TMSI Refa 8
Dear ddvlamin,
from what you are posting, I guess that your device is not sending the samples 256Hz as expected. Did you actually request 256 Hz ? My assumption is that the requested frequency is not considered by the OS driver (should it consider it invalid ?) and falls back to a different but fixed sampling frequency which the acquisition driver does not expect. Did the spec of this new hardware change since the first version you had ? If this is a sampling frequency problem, we may have to put some new values in the combo box so that you can chose values that the hardware appreciate. I'll let you know how to do that if you confirm this idea.
About the native Refa Driver, Baptiste Payan is currently working on it. I'll invite him to follow this post. If you want to give a try to this driver, you'll have to switch to the wip-bpayan branch of the acquisition server project. I'll then let him guide you with his work.
Best regards,
Yann Renard
from what you are posting, I guess that your device is not sending the samples 256Hz as expected. Did you actually request 256 Hz ? My assumption is that the requested frequency is not considered by the OS driver (should it consider it invalid ?) and falls back to a different but fixed sampling frequency which the acquisition driver does not expect. Did the spec of this new hardware change since the first version you had ? If this is a sampling frequency problem, we may have to put some new values in the combo box so that you can chose values that the hardware appreciate. I'll let you know how to do that if you confirm this idea.
About the native Refa Driver, Baptiste Payan is currently working on it. I'll invite him to follow this post. If you want to give a try to this driver, you'll have to switch to the wip-bpayan branch of the acquisition server project. I'll then let him guide you with his work.
Best regards,
Yann Renard
Re: ANT TMSI Refa 8
I thougth, for these recordings I specified 128Hz. I tried different settings before, all giving the same result. The amplifier supports sampling frequencies of 128, 256, 512, 1024 and 2048Hz (see http://www.tmsi.com/?id=7). Anyhow I guess the amplifier is working correctly at the asked frequency as these "gaps/errors" do not occur if I use the trial version of ASALab (ANT) with sample frequencies of 256Hz.
Re: ANT TMSI Refa 8
Dear ddvlamin,
the sample files you sent me are 256 Hz, right ? I'm not saying that your device is not able to acquire at 256 Hz, just that the sampling rate request from the driver may not be considered by the device.
Yann
the sample files you sent me are 256 Hz, right ? I'm not saying that your device is not able to acquire at 256 Hz, just that the sampling rate request from the driver may not be considered by the device.
Yann
Re: ANT TMSI Refa 8
Dear Yann,
The file within Refa8_Test2.zip is indeed sampled at 256Hz.
However, I do not really understand what you are saying.
I know that the drivers from TMSI support and consider the request of sampling at 256Hz as it works in ASALab. In OpenVibe I also specified 256Hz in the acquisition server, just as I do in ASALab. So the only thing that can go wrong is the communication with the NexusDLL and the new driver that I installed from TMSI? Then I fear that the only solution is the native implementation of a Refa driver, correct?
Dieter
The file within Refa8_Test2.zip is indeed sampled at 256Hz.
However, I do not really understand what you are saying.
I know that the drivers from TMSI support and consider the request of sampling at 256Hz as it works in ASALab. In OpenVibe I also specified 256Hz in the acquisition server, just as I do in ASALab. So the only thing that can go wrong is the communication with the NexusDLL and the new driver that I installed from TMSI? Then I fear that the only solution is the native implementation of a Refa driver, correct?
Dieter
Re: ANT TMSI Refa 8
Dear ddvlamin,
thank your for the additional informations. What I was pointing out was the possibility that the OS driver silently ignores the requested sampling rate and falls back to a default value. For example, suppose the default sampling rate of the device is 250 Hz. Now in the acquisition server you request 256 Hz. The OS driver ignores this and it sends 250 samples a second to the acquisition drivers which fills the missing 6 samples sometimes in order to actually have a 256 Hz signal. Then you finally get a wrong 256 Hz GDF file... To be sure this scenario is not happening, try requesting different sampling rates in the acquisition server, e.g. 128 Hz, 256 Hz, 512 Hz, 1024 Hz and see what happens.
On the other hand, I requested Baptiste to let you know when his branch is ready. He commited a few things this morning and should test his development to let you know whether his driver is ready to test or not.
Yann
thank your for the additional informations. What I was pointing out was the possibility that the OS driver silently ignores the requested sampling rate and falls back to a default value. For example, suppose the default sampling rate of the device is 250 Hz. Now in the acquisition server you request 256 Hz. The OS driver ignores this and it sends 250 samples a second to the acquisition drivers which fills the missing 6 samples sometimes in order to actually have a 256 Hz signal. Then you finally get a wrong 256 Hz GDF file... To be sure this scenario is not happening, try requesting different sampling rates in the acquisition server, e.g. 128 Hz, 256 Hz, 512 Hz, 1024 Hz and see what happens.
On the other hand, I requested Baptiste to let you know when his branch is ready. He commited a few things this morning and should test his development to let you know whether his driver is ready to test or not.
Yann
Re: ANT TMSI Refa 8
Dear ddvlamin,
I am working on the driver "TMSI Refa 32" for openvibe. I have finished to test my branch, if you want to give a try to this driver, you'll have to switch to the "wip-bpayan" branch of the acquisition server project.
After you'll launch the OpenViBE acquisition server, you'll have to switch to the "TMSI Refa32B" driver. In the property windows you'll can see if your amplifier is recognize. (field "Device Master" is empty if no device detected)
For information: The field about number of channels is unused, because the driver send information of all channels detected.
This driver can use master and slaves amplifier but I never test it. That's why, I don't know if this option works.
I hope this driver resolve your problem.
Baptiste
I am working on the driver "TMSI Refa 32" for openvibe. I have finished to test my branch, if you want to give a try to this driver, you'll have to switch to the "wip-bpayan" branch of the acquisition server project.
After you'll launch the OpenViBE acquisition server, you'll have to switch to the "TMSI Refa32B" driver. In the property windows you'll can see if your amplifier is recognize. (field "Device Master" is empty if no device detected)
For information: The field about number of channels is unused, because the driver send information of all channels detected.
This driver can use master and slaves amplifier but I never test it. That's why, I don't know if this option works.
I hope this driver resolve your problem.
Baptiste
Re: ANT TMSI Refa 8
Hi,
I contacted TMSI and they said the default sample frequency is 2048Hz. However, even when I request for that sample frequency the same errors occur, both with the native driver and the nexus dll.
I also tried out the new native driver, but the same problem still exists: some samples are missing (again I include some test file that are recorded with the native driver: http://www.thewired.be/blog/wp-content/ ... driver.zip). What I also noticed is that the EEG displayed on the screen is delayed for many seconds. I tested this by chewing, but only saw these artefacts after about 10 seconds appear on my screen.
A second thing I noticed is that even with the old amplifier and drivers, OpenVibe still presents warnings about dummy values, but it stops after a few seconds, while with the new amplifier it remains.
And a third thing. If I request to record 32 channels, it still gives me 40 (or 42). Probably these are the auxiliary channels.
EDIT: forget that, I forgot your remark above about the channels:
Kind regards,
Dieter
I contacted TMSI and they said the default sample frequency is 2048Hz. However, even when I request for that sample frequency the same errors occur, both with the native driver and the nexus dll.
I also tried out the new native driver, but the same problem still exists: some samples are missing (again I include some test file that are recorded with the native driver: http://www.thewired.be/blog/wp-content/ ... driver.zip). What I also noticed is that the EEG displayed on the screen is delayed for many seconds. I tested this by chewing, but only saw these artefacts after about 10 seconds appear on my screen.
A second thing I noticed is that even with the old amplifier and drivers, OpenVibe still presents warnings about dummy values, but it stops after a few seconds, while with the new amplifier it remains.
And a third thing. If I request to record 32 channels, it still gives me 40 (or 42). Probably these are the auxiliary channels.
EDIT: forget that, I forgot your remark above about the channels:
When exactly did you buy your Refa amplifier? Did you buy it with TMSI or ANT? Maybe you can send me the drivers you are using through email. Did you also receive a copy of portilab (does it work?), because this software does not seem to work with my amplifier, which is off course very strange? Something must have changed, or the drivers from ANT or the amplifier?For information: The field about number of channels is unused, because the driver send information of all channels detected.
Kind regards,
Dieter
Re: ANT TMSI Refa 8
Dear ddvlamin,
I think the delay you are talking about is strange. Can you send me both the acquisition server and the designer log files while recording a session please ?
I watched your recorded files, computed a spectrum on a second of signal for each, I see that the artifacts are really regular (16Hz, 32Hz, 48Hz, 64Hz...)
Yann
I think the delay you are talking about is strange. Can you send me both the acquisition server and the designer log files while recording a session please ?
I watched your recorded files, computed a spectrum on a second of signal for each, I see that the artifacts are really regular (16Hz, 32Hz, 48Hz, 64Hz...)
Yann
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Dear ddvlamin,
I think I have the old version because we bought The refa amplifier in 2007, to the ANT company and We hadn't receive a copy of portilab.
Best regards,
Baptiste
I think I have the old version because we bought The refa amplifier in 2007, to the ANT company and We hadn't receive a copy of portilab.
Best regards,
Baptiste
Re: ANT TMSI Refa 8
Dear Baptiste,
can you send a copy of your OS drivers to ddvlamin so he can give it a try ?
Yann
can you send a copy of your OS drivers to ddvlamin so he can give it a try ?
Yann