XBody Newave User Manual page 42

User Manual
Version: 1.7
8.1.4 Hardware protection for stimulation
The design of the electronics has a 10mA current limit on the DC output of the stimulation channel. A
capacitor is located after the limit in order to provide the necessary stimulation power. As a last limit
a 138mA current limit and with a 4.7 Ohm resistance is used, which applies as a final regulation on
the current output. Each channel has a maximal 50V voltage that is ensured by a P6SMB suppressor
diode.
Because the waveform is fixed, and the maximal duty cycle is 0.16 we can compute the maximal RMS
Voltage with the following formula:
√ ∫ (
,from which we can get:
√ √
=50*0.4=20V
From this we can compute the maximal EMS current on 500 Ohm, which is 20/500=40mA which is
below the limitation (50mA) in point 201.12.4.104 of the standard.
At its minimal setting the output not exceeds 2% of the maximal value since it is 0mA.
The input of the device is expected to be between 100-240VAC. The power supply of the device
works with 90-266 VAC according to the data sheet of the power supply. This means that ±10% of the
input voltage fluctuation does not affect the essential performance.
8.1.5 Software solutions controlling the output
The output voltage has a dual control of intensity. This means that each channel has a regulator
between 0-100% with 1% step and there is a master regulator that has a multiplicative effect on the
channels, which is also allowed 0-100% with 1% step. The step is ensured in the software since the
intensity can be increased two ways, repetitively pressing the + button or using the slider. The auto
repeat on the button is not enabled, thus one interaction can lead in 1% increase only. Using the
slider the intensity can be increased by swiping. Since the swipe interaction generates mouse move
events repetitively (independently from the speed of swiping) it sequentially increases the intensity
step by step. Also the sudden (quick) increase is prohibited and handled in a way the swiping speed is
lowered by the software thus one swipe cannot result in quick increase. Since the maximal channel
intensity is 50V this means that if one of the regulator is at the maximal level, the maximal step is
0.5V.
If the output is interrupted or the stimulation is stopped or paused the master regulator is
automatically reset to 0%, which means that if the stimulation is restarted or continued then it is set
to its minimal position.
Since the stimulator can provide higher output values than 10mA or 10V, the status of the
stimulation is indicated on the user interface. If the stimulation is active a notification can be seen on
the screen which informs the client that the output is active.
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