Rockwell Automation System Design for the Control of Electrical Noise - Manual (Page 66)

Publication GMC-RM001A-EN-P — July 2001
7-8 Power Distribution
Dual Switch-Mode 24V dc PSU Example
In the figure below, dirty and clean zone loads have dedicated power
supplies. Segregation and filtering are used (as in Figure 7.5) to
reduce the noise in the power supply for clean zone needs.
Figure 7.7
24V dc power distribution with dual PSU
Note: Clean PSU is mounted in the dirty zone because it typically
generates noise in the switching process.
24V dc PSU AC Filter
+24V 24V com
Dirty Zone
Clean Zone
Dirty Load
Clean Load
Segregation
De-coupling
capacitor
24V dc PSU Filter AC
Filter
+24V 24V com