Basler Electric DGC-2020 - Manual (Page 383)

arrangement shown in Figure 9-11 gives the external device control of the analog speed bias signal when
the generator breaker is open, and the LSM-2020 has control when the generator breaker is closed.
Figure 9-11. External Control Device with DGC-2020 — LSM-2020 System, Method 1
Method 2
An alternate method of interfacing the DGC-2020 and an external device to drive the governor bias
voltage can be done by placing the bias output of the LSM-2020 and the bias output of the external
device in series. If the output of the LSM-2020 is connected in series with the bias output of the external
synchronizer as shown in Figure 9-12, both devices will be allowed to exercise control over the bias input
of the governor.
Be sure the LSM and the external device are never in a situation where they oppose each other. Both
devices should not be trying to exercise dynamic control at the same time. For example, an external
synchronizer should only be used with a DGC-2020 that does not have the synchronizer option, or has
the synchronizer function disabled.
In addition, be sure the analog voltage range limits of the governor or AVR inputs are not exceeded.
Exceeding these limits may result in undesired system operation, or force a device into an error or fault
state.
If it is desired to have raise/lower inputs to control speed, use a motor operated potentiometer, as the
external device. Note that if speed trim is enabled in the DGC-2020 and the generator’s breaker is closed,
the DGC-2020 will drive the system to the speed trim setpoint regardless of the presence of the external
device. When the generator breaker is open, speed trim is disabled, and the external device will control
machine speed.
A similar arrangement may be used for the bias input of an AVR if an external device is required for
voltage control.
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Ethernet
LSM-2020
AVR+
AVR-
AVR’
GOV+
GOV-
GOV’
CANL
CANH
GND
V+
IN-
I+
LS+
LS-
LS’
B-
B+
GND
Governor
Analog
Aux
Input
DGC-2020
CANL
CANH
SHIELD
P0071-83
12 or
24 Vdc
To System Load
Share Line
External
Device Analog
Aux
Output
+
-
-
+
Breaker B
Contact
Breaker A
Contact
9400200990 Rev X DGC-2020 LSM-2020 (Load Share Module) 9-13