Watlow Electric Micro-Based Autotuning Control SERIES 980/985 - Manual (Page 10)

Line Filtering Configurations For Controls
Figure 3 -
These three diagrams show you filter configurations for removing input power
noise. Choose the one best suited for your system. For very dirty or critical
applications - use
a microcomputer-regulated power supply or Uninterruptable
Power Supply (U.P.S.) Don’t fasten common mode line filters or filters with
metal cases to metal that is at ground potential. This prevents ground loops
and maintains filter effectiveness.
Differential Mode
Filter
Wiring
Ll D.M. Line Filter
.
NOTE: Keep filters
12 inches or less
from the control.
Minimize the line
distance where
nolse can be re-
introduced to
control.
Control
Common Mode Filter
Wiring
2
NOTE: To prevent
ground loops do not
fasten common
mode line filters or
filters with metal
cases to metal that
is at ground poten-
tlal. Doing so will
reduce filter effec-
tiveness.
Figure 5 -
Combination
Differential/
Common Mode Filter
Wiring
C.M. Line Filter
Control
I
Ground
Control
10 WATLOW Series 980/985 User's Manual Install and Wire, Chapter 2