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EMG-USB2+ Trigger Signal from Another Device


We are using the EMG-USB2+ DAQ to sample data from 3 HD-EMG arrays via 3 multiple input ports and are sending this data to Matlab in real-time via OTBioLabLight – Version 1.5.7. We would like to create a trigger signal at the beginning of data acquisition to synchronize the HD-EMG data with data simultaneously collected from other devices. In a past study ( using OT Bioelettronica devices, a trigger signal was sent to a Quattrocento DAQ from a National Instruments DAQ. We are trying to figure out:

  1. Can a trigger signal from a National Instruments DAQ (or another device) be sent to the EMG-USB2+ via the trigger connector on the rear panel of the device?
  2. If a trigger signal can be sent to the EMG-USB2+, do we need to use a specific type of trigger signal?
  3. How does the trigger signal appear in the data?
  4. Can we receive the trigger signal data in Matlab using OTBioLabLight – Version 1.5.7?

Thank you for your help!

- Alex

Fabio ha reagito a questo messaggio.

Hi, thank you to have contacted us, here the answers to your questions:

  1. You can acquire external signals with the EMG-USB2+ through the AUX channels in the back panel. The AUX channels (auxiliary channels) have bnc connector and can be visualized in the same way of the channels in the front panel, so you have to configure it in the software to visualize it. The trigger connector is a particular back panel input, if you connect a signal in it and a visualization in OT Biolab+ software is started, everytime that the device recognizes a rising edge in the signal, a recording is automatically started in the software and everytime that a falling edge is recognized, the recording is stopped. in this way you can obtain some files with a duration equal to the time the signal was high. So, it depends on what is your need, if you want to syncronize signals coming from different devices through a common trigger signal, this trigger signal should be acquired through a classic aux channel and then doing the reallignment in post processing, otherwise if you want files related to a specific portion of an external signal you can use the trigger connector
  2. There aren't specific requirements about the signals which can be acquired through the AUX channels, the only think is that these must be signals between +5 and -5 Volts.
  3. The signal will be provided in the exact same way of the other channels. If you use OTBiolab+ software, just configure the AUX where you want to connect the trigger signal, by just choosing in the options "Direct Connectio to Auxiliary Input" and any of the sensor options. In this way the signal will be visualized as a single channel track in the software.
  4. You can also do it with MATLAB, just add the AUX channel in the number of channels expected from the devices.

Let me know if you require other clarifications or help about any doubts.

ahspragu ha reagito a questo messaggio.