GW Instek SPS Series - Manual (Page 19)

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6-2. Setting Current Limit
(1) Determine the maximum safe current for the device to be powered.
(2) Temporarily short the (+) and (-) terminals of the power supply together with a test lead.
(3) Rotate the COARSE VOLTAGE control away from zero sufficiently to have the CC indicator lightened.
(4) Adjust the CURRENT control for the desired current limit. Read the current value on the Ammeter.
(5) The current limit (overload protection) has now been preset. Do not change the CURRENT control setting after this
step.
(6) Remove the short between the (+) and (-) terminals and hook up for constant voltage operation.
6-3. Constant Voltage / Constant Current Crossover Characteristic
The working characteristic of this series is called a constant voltage/constant current automatic crossover type. This
permits continuous transition from constant current to constant voltage modes in response to the load change. The
intersection of constant voltage and constant current modes is called the crossover point. Fig.6-1 shows the
relationship between this crossover point and the load.
For example, if the load is such that the power supply is operating in the constant voltage mode, a regulated output
voltage is provided. The output voltage remains constant as the load increases, up until the point where the preset
current limit is reached. At that point, the output current becomes constant and the output voltage drop is
proportioned to further increases in load. The crossover point is indicated by the front panel LED indicators. The
crossover point is reached when the CV indicator goes out and the CC indicator is on.
Fig. 6-1 Constant Voltage/Constant Current Characteristic.