Rockwell Automation System Design for the Control of Electrical Noise - Manual (Page 96)

Publication GMC-RM001A-EN-P — July 2001
11-6 Measuring Noise Reduction Effectiveness
For BNC cases (as shown in Figure 11.4) refer to the following list of
suppliers:
• Pomona Electronics, Part # 3752
• RS Components, Part # 189-0258
For more information on these and other suppliers, refer to
Appendix B.
Figure 11.4
High-pass filter construction, 150 kHz, 1 pole (signal flow is left to right)
Grounding Your Probe (reference ground)
If the panel is plated and everything is bonded to it then the nearest
point on the panel is the best reference ground point. With proper
bonding the whole panel is a ground plane and the ideal reference.
With a painted panel it is almost impossible to define a good ground
because all the components are at different RF potentials. However,
because a properly bonded panel (even one that’s painted) maintains
the same electrical potential at all points, it is still the best reference
ground.
ATTENTION
!
To avoid personal injury or damage to equipment,
always connect the probe ground clip to reference
ground. Connecting the ground clip to line voltage
may cause the scope chassis and controls to reach
potentially lethal line voltage.