Operating the Power Supply Locally
3
Series N8700 User’s Guide
51
Resistance Programming of Output Voltage and Current
Resistances of 0 - 5 kΩ or 0 - 10 kΩ can be selected to program the
output voltage and current limit from zero to full scale. Internal
current sources supply a 1 mA current through the external resistors.
The voltage drop across the resistors is used as the programming
voltage for the power supply. To maintain the temperature stability
specification of the power supply, only use resistors that are stable
and low noise, with a temperature coefficient less than 50 ppm.
Set the power supply to resistance programming as follows:
1
Make sure that the power supply is turned off.
2
Set SW1 setup switch 1 (for voltage) and 2 (for current) to the UP
position.
3
Set SW1 setup switch 3 to select programming resistance range
according to the table following these procedure steps.
4
Set SW1 setup switch 7 (for voltage) and 8 (for current) to the Up
position to enable resistance programming.
5
Connect a short between J1 pin 8, J1 pin 12, and J1 pin 23 (see
figure).
6
Connect the programming resistors to the mating plug of J1 as
shown in the following figure. A variable resistor can control the
output over its entire range, or a combination of variable resistor
and series/parallel resistors can control the output over a
restricted portion of its range.
7
Set the programming resistors to the desired resistance and turn
the power supply on. Adjust the resistors to change the power
supply output.
The analog control circuits let you set the output voltage and current
limit up to 5% over the model-rated maximum value. The power
supply will operate within the extended range, however it is not
recommended to operate the power supply over its voltage and
current rating, and performance in this region is not guaranteed.
SW1 switch 3
Voltage Programming
(J1 pin 9)
Current programming
(J1 pin 10)
Down (default)
0 –
5 kΩ
0 –
5 kΩ
Up
0 –
10 kΩ
0 –
10 kΩ
