Chapter 1
Getting Started
NI PS-15 Power Supply User Manual
1-4
ni.com
Output Voltage Potentiometer
Note
You must open the protective flap to turn the potentiometer.
Output voltage from the NI PS-15 is set by the output voltage
potentiometer, shown in Figure 1-2. The factory setting output voltage
is 24.1 V ±0.2% (at full load when the power supply is cold), and the
potentiometer allows the output voltage to be adjusted from 24–28 V
on any unit. The output voltage may be adjusted above 28 V by the
potentiometer, but voltages beyond 28 V are
not
guaranteed.
Note
Output voltages greater than 28 V are not supported on an NI PS-15 unit.
DC OK LED
This green LED indicates the status of available DC power through the
output terminals. If the LED is lit, DC output of greater than 21 V is
available for use through the output terminals. If the LED is not lit, DC is
not currently available. The DC OK LED is wired internally to the power
conversion circuitry prior to the output filtering stage, as shown in
Figure 1-1.
If the DC OK LED does not light when power is provided through the input
terminals, it may indicate a problem with the power supply. Contact
National Instruments for more details.
Input Terminals
Caution
National Instruments recommends that you wire all three input terminals for
proper operation of the NI PS-15.
The NI PS-15 power supply derives power through the input terminals
on the front panel, shown in Figure 1-2. There are three terminals
corresponding to the Neutral input, the Line (or hot) input, and the
Protective Earth (PE) input. The NI PS-15 rectifies both single-phase and
two-phase AC input. The Neutral input terminal provides a MAINS return
path for the input circuitry. The Line input is the primary power input for
the supply. The PE input corresponds to an earth ground. As shown in
Figure 1-1, the power supply case itself is grounded to the PE input.
