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GMC-I Gossen-Metrawatt GmbH
5.3 Regulating Output Voltage
Functions
The control inputs Uset+ (non-inverting) and Uset GND (inverting)
allow for adjustment of output voltage Uout with an external
control voltage U
SU
.
The following applies in the constant voltage regulating mode:
Uout = USET + U
SU
x k
SU
USET
= voltage setpoint selected manually or via interface
k
SU
= voltage control coefficient = Uoutnom/ 5 V
Max. adjusting error: ± 0.05% Unom ± 0.2% setpoint value
The voltage control input functions as a differential voltage input:
Uset+
= non-inverting input:
U
SU
= 0 ... +5 V for Uout = 0 V ... Uoutnom
Uset GND
= inverting input:
U
SU
= 0 ... -5 V for Uout = 0 V ... Uoutnom
Input resistance is 10 k
Ω
in both cases.
Note:
The control inputs are not floating inputs: Their reference point,
AGND, is connected to the negative output pole. Connecting
grounded circuits to the control input may result in erroneous
adjustments due to leakage current or ground loops.
If the reference point of control voltage U
SU
is connected to the
negative output pole at the load side, the inverting input must be
connected to this point in order to prevent influences due to
voltage drops at the output lead (connection b in Figure 5.3a). If
control voltage is isolated from the output, Uset GND must be
connected with AGND (connection a in Figure 5.3a).
U
SU
can also be applied as an alternating voltage, for example in
order to superimpose manually selected direct voltage USET with
interference signals. The maximum operating frequency of
modulated output voltage depends upon voltage amplitude, the
current limiting setting and load, and thus cannot be defined with
a simple formula. It is increased as amplitude is decreased, and
as current limiting and load are increased.
If remote output voltage adjustment is to be accomplished by
means of a potentiometer, wiring can be configured as shown in
the example in Figure 5.3b.
5.4 Regulating Output Current
Functions
The control inputs Iset+ (non-inverting) and Iset GND (inverting)
allow for adjustment of output current Iout with an external control
voltage U
SI
.
The following applies in the constant voltage regulating mode:
Iout = ISET + U
SI
x k
SI
ISET
= current setpoint selected manually or via interface
k
SI
= current control coefficient = Ioutnom / 5 V
Max. adjusting error: ± 0.1% Unom ± 0.3% setpoint value
The current control input functions as a differential voltage input:
Iset+
= non-inverting input:
U
SI
= 0 ... +5 V for Iout = 0 A ... Ioutnom
Iset GND
= inverting input:
U
SI
= 0 ... -5 V for Iout = 0 A ... Ioutnom
Input resistance is 10 k
Ω
in both cases.
Note:
The control inputs are not floating inputs: Their reference point,
AGND, is connected to the negative output pole. Connecting
grounded circuits to the control input may result in erroneous
adjustments due to leakage current or ground loops.
If the reference point of control voltage U
SI
is connected to the
negative output pole at the load side, the inverting input must be
connected to this point in order to prevent influences due to
voltage drops at the output lead (connection b in Figure 5.4a). If
control voltage is isolated from the output, Iset GND must be
connected with AGND (connection a in Figure 5.4a).
U
SI
can also be applied as an alternating voltage, for example in
order to superimpose manually selected direct current ISET with
interference signals. To a great extent, the maximum operating
frequency of modulated output current depends upon the output
current value, as well as the voltage amplitude which results from
the prevailing load, and thus cannot be defined with a simple
formula. It is increased as amplitude is decreased, and as load is
increased.
If remote output current adjustment is to be accomplished by
means of a potentiometer, wiring can be configured as shown in
the example in Figure 5.4b.
Figure 5.3a
Wiring for Voltage
Regulation with
External Voltage
Figure 5.3b
Wiring for Voltage
Regulation with
External
Potentiometer
Analog Interface
+15 V
AGND
T
TRIGGER
−
Uset +
Uset GND
M/S Uset +
Settings:
USET = 0
ISET = Iset
OUTPUT on/off
Uout
a)
I
SU
Load
REF 02
IN
OUT
+5V
2k
U
SU
SSP KONSTANTER
+
b)
−
SENSE
+SENSE
Analog Interface
+15 V
AGND
T
TRIGGER
−
Uset +
Uset GND
M/S Uset +
U-MONITOR
Iset +
Iset GND
+OUT
I-MONITOR
Settings:
USET = 0
ISET = Iset
OUTPUT on/off
Uout
SSP KONSTANTER
–OUT
Load
−
SENSE
+SENSE
U-MONITOR
Iset +
Iset GND
+OUT
I-MONITOR
–OUT
Figure 5.4a
Wiring for Current
Regulation with
External Voltage
Figure 5.4b
Wiring for Current
Regulation with
External
Potentiometer
Analog Interface
+15 V
AGND
T
TRIGGER
−
Uset +
Uset GND
M/S Uset +
Settings:
USET = Uset
ISET = 0
OUTPUT on/off
Uout
a)
I
SI
Load
REF 02
IN
OUT
+5V
2k
U
SI
SSP KONSTANTER
+
b)
−
SENSE
+SENSE
Analog Interface
+15 V
AGND
T
TRIGGER
−
Uset +
Uset GND
M/S Uset +
U-MONITOR
Iset +
Iset GND
+OUT
I-MONITOR
Settings:
USET = Uset
ISET = 0
OUTPUT on/off
Uout
SSP KONSTANTER
–OUT
Load
−
SENSE
+SENSE
U-MONITOR
Iset +
Iset GND
+OUT
I-MONITOR
–OUT
Iout
Iout
