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Rockwell Automation Publication 1407-UM002B-EN-P - February 2019
Chapter 3
CGCM-DLR Unit Operation
Discrete Inputs - Remote Excitation Enable
The remote excitation enable input is a 24V DC input. When 24V DC is applied
to the input, CGCM-DLR unit excitation is permitted.
The remote excitation enable input terminals are labeled EX-D(+) and EX-D(-).
Analog Outputs
The unit has two types of analog outputs: excitation output and real power load
sharing.
Excitation Output
The CGCM-DLR unit Pulse Width Modulated (PWM) power stage provides
DC generator exciter field current. The excitation power stage is designed to
accommodate up to 125V DC (nominal) field voltages.
See
for a description of operation.
Care must be taken that the field resistance does not allow more than 15 A DC to
flow continuously at rated field voltage.
Minimum resistance for common voltages is given in
The CGCM-DLR unit excitation output is equipped with a high-speed circuit
for detecting a shorted output. The excitation output is clamped at a low level
when a low impedance connection is detected. The CGCM-DLR unit indicates
that the clamp is active by setting Spare2 bit in the Scheduled Read Data Table.
The Spare2 bit indication is reset by either setting the tag SoftwareExcEN = 0 or
by cycling the control power to the CGCM-DLR unit.
A loss of EtherNet/IP network communication with the host Logix controller
causes the CGCM-DLR unit to automatically shut down generator excitation.
The excitation output terminals are labeled EXC(+) and EXC(-).
IMPORTANT
For generator excitation to occur, excitation must be enabled in software,
an active EtherNet/IP
®
connection must be present, and a 24V DC signal
must be applied to the remote excitation enable input.