Rockwell Automation System Design for the Control of Electrical Noise - Manual (Page 50)

Publication GMC-RM001A-EN-P — July 2001
5-4 Filtering Noise
Performance Test Set-up
The filter performance test included the following components:
• 24V dc power supply with grounded common filter
• Filter mounted to DIN rail
• Relay coil to simulate an inductive load
• 100M Hz sampling digital storage oscilloscope
• Test components mounted on a large zinc plated steel panel
Figure 5.4
Filter test block diagram
Test Results
Filter
Measurement point
Filter under
test
24V dc
PSU
Ground Plane - conductive metal panel Suppression
Switched load
1 m (39 in.) wire
This test condition: With
No filter: With
Capacitor only: With Capacitor
and ferrite sleeve:
No Suppression 200V pk 5.5V pk 674mV pk
R/C
Across coil
100R/0.1uF 5.5V pk 932mV pk 168mV pk
R/C
Across switch
100R/0.1uF 2.5V pk 103mV pk 70mV pk
Transorb
Across coil 14.9V pk 1.8V pk 658mV pk
Transorb
Across switch 8.1V pk 1.4V pk 1.2V pk
Diode 12V pk 63mV pk 63mV pk
Note: Voltages were measured between the measurement point and the ground plane (refer to Figure 5.4 for
exact location.