Fluke Biomedical 190M III Series, Руководство пользователя

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Medical ScopeMeter
Tips
57
Independently Floating Isolated Inputs
The test tool has independently floating isolated inputs. You can use the independently floating
isolated inputs to measure signals that are independently floating from each other. Independently
floating isolated inputs offer additional safety and measurement capabilities compared to inputs
with common references or grounds.
Each input section (A, B, C, D, METER INPUT) has its own signal input and its own reference
input. The reference input of each input section is electrically isolated from the reference inputs
of the other input sections. The isolated input architecture makes the test tool about as versatile
as having four independent instruments. The advantages of having independently floating
isolated inputs are:
• Simultaneous measurement of independently floating signals.
• Additional safety:
◦ Since the commons are not directly connected, the chance of causing short circuit when
measuring multiple signals is greatly reduced.
◦ When measuring in systems with multiple grounds, the ground currents induced are kept
to a minimum.
Because the references are not connected together inside the test tool, each reference of the
used inputs must be connected to a reference voltage. Independently floating isolated inputs are
still coupled by parasitic capacitance. This can occur between the input references and the
environment, and between the input references mutually. See
Figure 35 . For this reason, you
should connect the references to a system ground or another stable voltage. If the reference of
an input is connected to a high speed and / or high voltage signal, you should be aware of
parasitic capacitance. See
Figure 35 , Figure 37 , Figure 38 , and Figure 39 .
Note
The input channels are electrically isolated from the USB ports and from the power
adapter input.