How to perform a Measurement?
So let's acquire the data and see the results. The high-speed camera is synchronized exactly to the analog data therefore we can
compare the switching times with analog voltage and current. The current is flowing through the fuse for approximately 20 msec
before it really switches off and we can see nicely when the spark switches the fuse off. It is also very nice to see the position of the
switch (on the left side of the fuse) as it goes to the off position.
The picture from the webcam is nice but doesn't show this at all. Because the webcam is neither clocked nor synchronized with
analog data, it is time-stamped as the picture comes into the computer. Therefore, we can see the switch off with a delay of
approximately 60 ms. In conclusion, webcams have two limitations: speed and time accuracy.
However, there is a way to reduce the timing inaccuracy by entering a camera delay. Usually, this delay is quite constant and can be
compensated. We can do this in the Settings by entering this value in the Delay field in the table. We will still have a time jitter of each
frame, which can be in the range of 30 ms or even more when the system is at the limit its performance, but here we can't
compensate it. If time accuracy is needed, we should look for clocked cameras like
.
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