AMETEK HPD Series Operation Manual - Manual (Page 34)

34
Section 4. Operation
Operating Modes
Constant
Voltage Mode
Operation
The power supply will operate in constant voltage (CV) mode whenever the load
current I
L
is less than the current limit setting I
SET
or: I
L
< I
SET
(Note: I
L
= V
SET
/ R
L
).
In CV, the power supply maintains the output voltage at the selected value (V
SET
)
while the load current I
L
varies with the load requirements.
To use the power supply in CV mode, either set the current limit to maximum by
turning the current control to its extreme clockwise position, or take the precaution
of setting a desired maximum current, and then set the voltage control to the desired
voltage.
Constant
Current Mode
Operation
The power supply will operate in constant current (CI) mode whenever the load
resistance is low enough that at V
SET
the load current would be greater than the
current limit setting I
SET
.
V
SET
-------------
I
SET
R
L
In CI mode, the power supply maintains the output current at the selected value (I
SET
)
while the output voltage varies with the load requirements.
Setting the
Current Limit
Set the Current Limit by following the steps below:
1. Connect a shorting lead across the output terminals.
2. Turn the voltage control a half-turn clockwise.
3. Set the desired maximum current limit by turning the current control slowly
clockwise to the desired level.
4. Disconnect the shorting lead from the output terminals. The power supply will
now automatically switch into current limiting mode (current regulation) as
soon as the preset current level is reached.
Setting the
Supply to
Operate in CI
Mode
To operate the supply in CI mode:
1. Set the current limit as described above.
2. Set the voltage control fully clockwise or to the compliance voltage of the
circuit.
As soon as the supply starts operating in current mode, the red current mode
LED will turn on.
22 Operating Manual for HPD Series Power Supply