Tips

7

Using the Independently Floating Isolated Inputs

ANALOG INPUT

 

 

DIGITAL CONTROLLER

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ANALOG GROUND

DIGITAL GROUND

Figure 44. Parasitic capacitance between probes,

instrument and environment

 

DC BUS

+

MOTION/MOTOR CONTROLLER

 

DIGITAL

 

M

GROUND

 

 

 

DC BUS

-

 

 

Figure 45. Parasitic capacitance between analog and

digital reference

Figure 46. Correct connection of reference leads

ANALOG INPUT

 

 

DIGITAL CONTROLLER

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DIGITAL

GROUND

Figure 47. Wrong connection of reference leads

Noise that is picked up by reference lead B can be transmitted by parasitic capacitance to the analog input amplifier.

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Fluke 192, 199, 196 user manual Tips Using the Independently Floating Isolated Inputs