Communication - Allen-Bradley 1407-CGCM User Manual

CGCM Unit Operation
The unit has two types of analog outputs: excitation output and real power load
sharing.
The CGCM 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.
Refer to Excitation Control Modes on page 44 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 Appendix D.
The CGCM unit excitation output is equipped with a high-speed circuit for
detecting a shorted output. The excitation output is clamped at a very low level
when a low impedance connection is detected. The CGCM 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 unit.
Note that a loss of ControlNet network communication with the host Logix
controller causes the CGCM unit to automatically shutdown generator
excitation.
The excitation output terminals are labeled EXC(+) and EXC(-).
Real-power load sharing terminals are provided to allow two or more CGCM
units or other compatible generator control devices (such as the Line
Synchronization Module, catalog number 1402-LSM) to load the generators
under their control such that the same per unit output is developed by each
generator.
Load sharing terminals are labeled LS(+) and LS(-).
Rockwell Automation Publication 1407-UM001H-EN-P - November 2014