Rockwell Automation 2755 Enhanced Decoder Series B - Manual (Page 330)

Output Module Applications G–2
Publication 2755-833
AC Output Module Application
Figure G.2 illustrates a typical AC output module application. When
using high impedance loads, you may have to add an additional
resistor (R) in parallel with the load. Select a value for R that
maintains a minimum current of 50 mA RMS through the output
module in the closed state.
Figure G.2 AC output module application
– 2 +
Fuse
Connector Block
Enclosure
Conduit Hole
AC Output Module➀
MOD 1-8
AC Source
➀ Output module functions as switch, not a power source.
R
Load
Note: For highly inductive or capacitive loads, make sure that the
current does not exceed the maximum ratings of the fuse or module.
You can use a diode to protect the module. See Figure G.3.
Using a Diode to Protect Output Module
Back EMF (Electromotive Force) is sometimes generated when an
inductive load is switched off. Back EMF takes the path of least
resistance into the output module, which may cause the module to
blow. To protect the module from back EMF, insert a diode in
parallel with the inductive device to dissipate back EMF.