Hobart 120CU20, Operation And Maintenance Manual With Illustrated Parts List

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OM-2228 / Operation and Maintenance Manual
120CU20 / Series 500120 / 400 Hz. Generator Set
October 15, 2013 Chapter 1-1
Page 18
(5) Engine Interface PC Board [EIB] (A2).
The EIB is common between all engine models and monitors coolant temperature, oil pressure,
battery voltage, and fuel tank level monitoring. The EIB is also responsible for the monitoring the
warning switches for high coolant temperature, low oil pressure, high air restriction, and low
coolant level (optional). The warning switches signal the EIB when a fault occurs, which then the
EIB relays this information to the CTL. The CTL will issue the command to the system that fits
the fault event.
The EIB also controls the power distribution in the control system, hour meter, lights, and the
engine starter operation.
Figure 8: Engine Interface PC Board.
(6) Engine Specific PC Board [ESB] (A1).
The ESB is unique only to the engine model used in the GPU purchased. The ESB is the primary
interface between the control system and the engine’s electronic control module. When the CTL
senses the engine start button has been pressed it signals to the ESB, which then communicates
to the engine control module what mode of operation is required (idle or rated speed).
The ESB controls the “
FREQUENCY ADJUST” switch that is used to enable the “ FREQUENCY
ADJUST ENABLE/DISABLE” potentiometer to test the over/under frequency fault limits of the
generator set system. The ESB also controls the “DATA REQUEST” button and diagnostic
indicator light to read the engine’s ECM diagnostic error codes.