User manual

16 GMC-I Gossen-Metrawatt GmbH
4.2 Output Current
4.2.1 Iout – Presently Measured Current Value
• The right-hand digital display [5] <Amp> indicates the measured
value Iout for current at the output.
• If output current is superimposed with an alternating current,
the arithmetic mean value is displayed.
• The 3½ place measured value display is refreshed approxi-
mately 3 times per second. Overflow is indicated for measured
values of greater than 19.99 at 20 A devices.
☞ Refer to chapter 1.4.3, Electrical Data, regarding measuring
range, measuring resolution and measuring accuracy.
4.2.2 Ilim – Limit Value for Iset
Function
• Defines the current adjustment setting range <Iset> [8].
• Prevents inadvertent, excessively high Iset values.
• If Ilim is set to 0 V (full left), the current adjusting
potentiometer <Iset> is disabled (e.g. for adjustment of output
current by means of the analog interface).
Setting Ilim
• The procedure for adjusting the Iset limit value is identical to the
procedure used to adjust the Uset limit value (4.1.2).
• The following controls and displays do however vary:
Left trimmer [7] <Ulim> → Right trimmer <Ilim> [11]
Left rotary knob [8] <Uset> → Right rotary knob <Iset> [10]
Left display [4] <Volt>→ Right display <Amp> [5]
Setting Range
• The <Ilim> potentiometer can be turned 270°, which
corresponds to a setting range of 0 A ≤ Ilim ≤ Inom.
• The 10 revolutions which are possible with the <Iset> rotary knob
[10] always correspond to a range of 0 A to Ilim.
4.2.3 Iset – Current Setpoint Value
Function
• Predefined current at which the consuming device is to be
operated.
Adjusting Iset
• The procedure for adjusting the current setpoint is identical to
the procedure used to adjust Uset (4.1.3).
• The following controls and displays do however vary:
Left rotary knob [8] <Uset> → Right rotary knob <Iset> [10]
Left display [4] <Volt>→ Right display <Amp> [5]
CAUTION!
The Uset value can also be changed when the KONSTANTER is not in
operation.
Setting Range
• The 10 revolutions which are possible with the <Iset> rotary knob
[10] always correspond to a range of 0 A to Ilim.
• The selection of a low value for Ilim allows for “finer” adjustment
of the Iset value.
The setting accuracy specified in chapter 1.4.3 makes reference
to the respectively displayed setpoint value.
• Overflow display
for settings of greater than 19.99 at 20 A devices:
4.3 OUTPUT – Switching the Power Output On and Off
• The power output is switched on and off with the red detented
key [9] <OUTPUT>.
• Pressing the <OUTPUT> key activates or deactivates the power
output.
OUTPUT OFF → OUTPUT ON
OUTPUT ON → OUTPUT OFF
• The power output can be deactivated for adjustments to Uset,
Ulim, Iset and Ilim in order to prevent damage to the consuming
device due to inadvertent, excessively high settings.
• If the power output is deactivated, “OUTPUT OFF”, the control
mode displays are switched off.
• If the power output has been deactivated by means of overtem-
perature protection, the yellow “Pmax” LED in the control mode
display [3] lights up. The output cannot be reactivated until the
KONSTANTER has cooled back down to its normal operating
temperature.
• Additional functions which may deactivate the power output:
✗ External control signal to TRG IN at the analog interface
(see also chapters 5.1 and 5.3)
✗ Overvoltage protection is triggered as soon as voltage at the
output terminals exceeds approximately 125% of Unom.
Cause:
– Excessively high setting for output voltage by means of
Uset control signal to the analog interface
– Voltage transient while switching an inductive consumer
– Unipolar power recovery from interconnected
consumers (e.g. DC motors) or from parallel
connected voltage sources
– Sensing mode operation: sensing leads connected with
reversed polarity or a power lead is/was interrupted
The “CV” display for constant voltage operation remains
illuminated. However, the display for output voltage or output
current drops to zero. At the same time, SIG1OUT indicates
“OUTPUT OFF”.
After eliminating the cause of triggering, the output can be
reactivated.
✗ Overtemperature protection is triggered
Cause:
– Impaired cooling, e.g. closed off air inlet
or air outlet vents
– Excessively high ambient temperature or load:
The device is able to deliver nominal power during
continuous operation at a maximum ambient
temperature of 40 °C (measured at air inlet vents)
– Defective fan
After the device has cooled sufficiently, the output is
reactivated automatically.
CAUTION!
The output terminals are not electrically isolated when the output is
deactivated.