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ScienceMode / ScienceMode4_P24

ScienceMode4 protocol for the P24 Science device which is a 8 channel stimulator for functional electrical stimulation (FES).
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Overshooting Issues on Biphasic Pulse Stimulation #3

Open angie906 opened 1 week ago

angie906 commented 1 week ago

Hello,

I would like to ask about the overshooting issues occurring both in the SMTP_PC_Software and in the code from GitHub (with the Python wrapper). In both cases, there is an issue of overshooting when stimulating biphasic pulses.

When the pulse changes its value, a peak voltage occurs that is beyond the expected value and is quite significant. For example, I should be getting 4.4V but I am getting 5.2V. (Please refer to the attached photo) Given that the overshooting is quite substantial, I would like to know if there's a way to fix it in software by changing the code or if I should add a filter in my resistor circuit.

Thank you very much in advance!

Screenshot 2024-06-28 at 10 32 27 AM
JensGruetzner commented 3 days ago

Hello,

can you say something about the measurement setup? What current is set and which resistor do you use to measure the voltage?

The plateaus of the pulses also seem to be higher than 4.4V, is that correct?

angie906 commented 2 days ago

Hello, thanks for your response.

It was 2mA and 2.2 Kohms resistor, so it should be around 4.4V peak. The Plateau is also a little bit higher but not too much (around 4.5~4.6V). I've checked with different frequency range(50-1000Hz) and pulse width(250-5000micro secs) setups. But for all cases, there were overshootings at least a bit from 9.4V(4.7V max) to 11.5V(5.55V max) peak to peak voltage.

Since the overshooting is quite big compared to the desired voltage, I wish we could figure out how to minimize it.