NDFs Not Same Length

[Kevan Hashemi]

A customer writes, "I've noticed that when i updated the LWDAQ (Neurorecorder 162), the duration of the NDFs is not 1 hr and not constant. please see below the length (seconds) of the last NDFs we had:
7257
7242
7240
7246
7246
7285
7257
7250
5640
7751
I found it easier to follow when the NDFs are set for 1 hr. Any chance to get this fixed?"

Dear Customer,

The files should all be 3600 s long. Something is wrong. Your one-hour files are up to 2.1 hours long. I have sent you by e-mail a Dropbox link. Please upload a few example NDF files to the Dropbox folder so I can examine them. I have a few questions:

(1) Do you see any errors in the Neurorecorder window? If so, please cut and paste the errors into a reply to this post.

(2) What value do you have for "Autocreate (s)"?

(3) Do you have the Synchronize button checked or unchecked?

Best Wishes, Kevan

[tawfeeq]

Hi Kevan,
I'v uploaded few NDFs samples.
(1) This error:
WARNING: Encountered 2 errors in received interval. (01-Jun-2023 00:05:58)

(2) "Autocreate (s)" = 3600

(3) Synchronize button is checked

Thank you!

[Kevan Hashemi]

Dear Tawfeeq,

Thanks for the NDF files. I open M1685495718 in the Neuroplayer, check the Verbose button, and step through the first second. This second contains eight errors.The clock is jumping:

Clock Error: index=59 current=78 previous=51
Clock Error: index=102 current=105 previous=78
Clock Error: index=223 current=133 previous=106
Clock Error: index=440 current=162 previous=135

I check "Sequential" and then press "Reload" to calculate the length of the file by counting the number clock messages. There should be 128 clock messages per second. By this measurement, the file is exactly 3600.0 s long. The same is true for the other four files. And yet each file took roughly two hours to record.

Diagnosis: There are two processes downloading data from the same data receiver. Your Neurorecorder is getting only half the data, so it's taking two hours to get one hour's worth of clock messages.

Suggestion: Check to see if you have two independent processes reading from your data receiver. You may have two Neurorecorders running, or you may have a Receiver Instrument running as well as your Neurorecorder Tool.

Explanation: The Neurorecorder runs as a separate process, using its own Receiver Instrument to download data from your Octal Data Receiver. If you open a Receiver Instrument using the Instrument Menu in your original LWDAQ program, this second Receiver Instrument will be entirely independent of your Neurorecorder. If you use this second Receiver Instrument to view live data from your Octal Data Receiver, you will have two processes downloading data, and each process gets only half.

So, I think that's what's happening. Apologies for confusion caused by the upgrade to LWDAQ 10.5.5.

Best Wishes, Kevan

[tawfeeq]

Dear Kevan,
Thank you!! Now it is running properly!
I had to close all and re-open again the new LWDAQ.

BTW, you may still run the Neuroplayer using the same window.

Best regards!
Tawfeeq

[Kevan Hashemi]

Dear Tawfeeq,

Glad things are working.

> BTW, you may still run the Neuroplayer using the same window.

Correct.

Open LWDAQ. In the Tool menu, select Neurorecoder. A new, independent process starts, and creates the Neurorecorder. We say you "spawn" a Neurorecorder. If you select Neurorecorder again, you spawn another Neurorecorder. You can spawn as many as you like. Maybe you have three data receivers and you want to record from all of them on the same computer.

When you select Neuroplayer in the LWDAQ Tool Menu, you spawn a Neuroplayer. You can spawn as many as you like. Maybe you want to export individual channels from the same NDF files into different directories. For that you need multiple Neuroplayers.

Multiple Neurorecorders and Neuroplayers can take a while to configure by hand. So we have the Startup Manager to automate starting up LWDAQ, spawning all the processes and configuring them to do what you want. The Startup Manager has its own manual:

http://www.bndhep.net/Electronics/LWDAQ/Startup_Manager.html

Best Wishes, Kevan