Set NVX36 channel properties to 32 channels

Obtaining data from various hardware devices
Post Reply
Dor mizrahi
Posts: 2
Joined: Wed Nov 29, 2017 7:24 pm

Set NVX36 channel properties to 32 channels

Post by Dor mizrahi »

hello everyone

I am using in OpenVibe in order to record EEG signals. I am using NVX36 and a simple open vibe chain with acquisition server and GDF writer.

after I connect the NVX36 and set the driver to "MCS NVX amplifier" there is a connection and the computer recognize the amplifier.

in the next step, I select the driver properties to be:
- number of channels: 32
- check impedance
and set apply (they are also 32 channel names saved)

but after I connect the server the properties are changed into a number of channels = 16, and 16 channels are received in the software, does somebody know how to receive 32 channels?.

thanks,
dor

jtlindgren
Posts: 775
Joined: Tue Dec 04, 2012 3:53 pm
Location: INRIA Rennes, FRANCE

Re: Set NVX36 channel properties to 32 channels

Post by jtlindgren »

Hello Dor,

according to the code, the MCS/NVX driver sets the channel count based on which device it identifies. If it's NVX_MODEL_16, it will set 16 channels. Some possibilities that come to mind,

- your device is wrongly identified
- there's a bug somewhere
- the library we build openvibe against is old

I'll try to forward the question to the driver contributor...


Cheers,
Jussi

jtlindgren
Posts: 775
Joined: Tue Dec 04, 2012 3:53 pm
Location: INRIA Rennes, FRANCE

Re: Set NVX36 channel properties to 32 channels

Post by jtlindgren »

I got the following thoughts from my contact with the MCS/NVX company (quoting),
There is not enough information for the reliable thoughts but the intelligent guess would be as following. As far as I know our amplifies are limited by the PC USB output power and provide the following configurations depending on their frequency settings:
4 channels at 50 kHz
16 channels at 10 kHz
24 channels at 5 kHz
And full 32 channels at lower frequencies.
So I believe the customer's NVX36 runs at 10 kHz and according to the technical specifications of the device (they shall be available on our web site and shall come with the device itself) yields only 16 channels. But I need more details about the NVX36 device configuration to provide more exact answer.
Perhaps it'd be useful to talk directly with them if the problem persists? We don't have these amplifiers at Inria Rennes.


Best,
Jussi

Dor mizrahi
Posts: 2
Joined: Wed Nov 29, 2017 7:24 pm

Re: Set NVX36 channel properties to 32 channels

Post by Dor mizrahi »

hi Jussi

thanks for the quick answer and the connection with the company. I will talk to them directly soon.

my colleague had a success with NEOREC software, he recorded 32 channels with the same USB connection (regular USB). if we succeed in the NEOREC this means that it can be possible also with OpenVibe.

thanks again, i will updated you with my results soon,
dor.

Post Reply