The GAM3.2 regards the rest of controller disabled when it cannot communicate with the rest of the controller (you could even
remove the GAM3.2 from the rack). As long as the GAM3.2 has power and the required wiring, you can use it for stand-alone
manual regulation.
When the controller is disabled, activate the
Stand-alone mode
digital input. The GAM3.2 then sends regulation signals based on
manual regulation inputs.
For analogue regulation, the GAM3.2 initially keeps the analogue output at a preset value. The GAM3.2 then adjusts the analogue
output in response to the manual inputs.
How it works when stand-alone mode is deactivated
If
Stand-alone mode
is deactivated, the controller determines the regulation mode and the regulation set point.
For analogue regulation, the GAM3.2 initially keeps the AVR analogue output at its last value. Before taking over control from
GAM3.2, the controller adjusts the regulation set point for bumpless transfer.
6.4 External communication
6.4.1 Overview
For certain actions and in some regulation modes it is possible to for the controller to receive its set point from an external source.
This source can for example be an analogue input, or a set point from CustomLogic, or Modbus.
This section gives an overview of how and when external communication is used in the controller, the inputs associated with it, and
the associated parameters.
INFO
To see the inputs and parameters mentioned in this section, you must have a governor and/or AVR configured in the
controller
Input/output
(relay output or analogue output).
6.4.2 External communication using an analogue input
To receive the controller regulation set points through the controller analogue inputs, the function must first be configured in
Configure > Input/output
. When the function is active, the controller ignores the internal set points that are calculated by the PMS
and uses the set points it receives from the analogue input instead.
You can either activate the function under
Configure > Parameters
, or by activating a digital input that is configured to activate the
function, or using Modbus.
Inputs
Configure these inputs under
Configure > Input/output
. Select the hardware module, then select the input to configure.
Table 6.3
Hardware required in addition to the minimum standard controller wiring
Function
I/O
Type
Details
Regulators > GOV > Frequency
offset [%]
Analogue
input
% of nominal
frequency
When configured, the controller receives the frequency offset
value from this analogue input. The offset is added or
subtracted from the nominal frequency.
f
new
= f
nom
+ (f
nom
× Frequency offset)
Regulators > GOV > Power set
point [%]
Analogue
input
% of nominal
power
When configured, the controller receives the active power set
point from this analogue input. The internal controller value for
the active power set point is ignored.
Regulators > AVR > Voltage
offset [%]
Analogue
input
% of nominal
voltage
When configured, the controller receives the voltage offset
value from this analogue input. The offset is added or
subtracted from the nominal voltage.
DESIGNER'S HANDBOOK 4189340911K UK
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