Service manual

3.4.1 Resistive Programming

Resistive programming requires connection of an external potentiometer or resistors between

terminals 21, 3, and 1 of JS1. Terminal 21 is a 10.0 V precision reference, terminal 1 is the

reference ground, and terminal 3 is the voltage set point input. Like front panel rotary control,

the precision reference produces a voltage across the potentiometer or resistors which is then

used to produce the voltage set point. Metal film resistors or a wire wound potentiometer will

result in the lowest temperature coefficient.

The current set point, over voltage trip, and over current trip can be programmed in the same

manner. Referring to the Table 3.1 for terminal identification, use terminal 22 to program the

current set point, terminal 4 to program over voltage trip, and terminal 23 to program over

current trip. The power supply has been calibrated to produce full scale output voltage and

current with 10.0 V inputs at the external reference input terminals. Furthermore, over voltage

and over current trip have been calibrated to trip at 110% full scale output voltage and current

with 10.0 V inputs at the external reference input terminals.

If the applied voltage at any input is greater than 12.50 V, the pgl (program line) LED will light

and the power supply will turn off.

Table 3.1 EXTERNAL PROGRAMMING PARAMETERS

TERM PARM DESCRIPTION

INPUT

RANGE (V)

OUTPUT

RANGE

VREF EXT

IREF EXT

TVREF EXT

TIREF EXT

Voltage Set

Current Set

Over Voltage Trip Set

Over Current Trip Set

0-10.0

0-100% FS Voltage

0-100% FS Current

0-110% FS Voltage

0-110% FS Current

3.4.2 Voltage Programming

Voltage programming is very similar to resistive programming. In this case, the voltage

reference, terminal 21 of JS1, is not used and an external voltage reference is applied to the

programming inputs directly. A 10.0 V voltage source placed between terminals 3 and 1 of JS1

will produce full scale output voltage.