External Voltage Control - HP 654 A Series Operating Manual

Caution
Each power supply has a reverse voltage protection diode across its output. If
a reverse voltage is applied, the supply cannot control the current conducted
through this diode. To avoid damaging the supply, never connect it in such
a way that a reverse voltage can force it to conduct current in excess of the
supply's maximum reverse diode current (see "Supplemental Characteristics").
External Voltage Control
The setup shown in Figure 4-9 allows an external dc voltage to program the power supply
output. A voltage applied to the voltage programming input programs the output voltage and
a voltage applied to the currrent programming input programs the output current. See Figure
4-3 and Table 4-1 for an explanation of these programming input connections.
Programming Series 654xA and 655xA Supplies
Wiring Considerations.
The input impedance of the analog input is 10 kO. If the output
impedance of your programming source is not negligible with this, programming errors will
result. Larger output impedances result in proportionally greater errors.
Be careful of capacitive coupling from the programming inputs to other lines wired to the
analog connector. Such coupling can cause output oscillations. You can minimize coupling
by bundling the IP, VP, and Common P lines and keeping them separated from other wires.
Twisting these three lines together is also recommended.
a) SERIES 654xA AND 655xA
fp
A-f
u
+ B
l+C -
m m
i+D -
ID
VOLTAGE PROGRAMMING SOURCE
0 TO -5 V
D
CURRENT PROGRAMMING SOURCE 1 0 TO +!0 V
El
CURRENT PROGRAMMING SOURCE ■ 0 TO -10 V
0
1
CURRENT PROGRAMMING SOURCE
FLOATING
0 TO 10 V
*MA)(MWPOTENTIW. BETWEEN -IP AfC iP IS 119 V
b) SERIES 657xA
Figure 4-9. External Voltage Programming
4-12 User Connections and Considerations
External Voltage Control