Multiple Loads; Local Voltage Sensing; Series 657Xa Supplies - HP 654 A Series Operating Manual

Multiple Loads
When connecting mnltiple loads to the power supply using local sensing, use separate wires to
connect each load to the output terminals (see Figure 4-4). This minimizes mutual coupling
effects and takes full advantage of the power supply's low output impedance. Each pair of
wires should be as short as possible and twisted or bundled to reduce lead inductance and
noise pickup.
If cabling considerations require the use of distribution terminals that are remotely located
from the supply, connect the output terminals to the distribution terminals by a pair of
twisted or bundled wires. Use separate wires for connecting each load to the distribution
terminals. In these circumstances, remote voltage sensing is recommended (see "Remote
Voltage Sensing"). Sense either at the remote distribution terminals or, if one load is more
critical than the others, directly at the critical load (see dashed lines in Figure 4-4). Note that
the power supply's voltage readback occurs at the sense terminals.
Figure 4-4. Multiple Load Connections (Remote Sensing Optional)
LOCAL VOLTAGE SENSING
Your power supply was shipped set up for local sensing. This means that the supply will sense
and regulate its output at the output terminals, not at the load. Since local sensing does not
compensate for voltage drops across screw terminals, bus bars, or load leads, local sensing
should only be used in applications that require low output current or where load regulation is
not critical.
Series 654xA and 655xA Supplies
Local sensing is obtained by placing the SENSE switch (see Figure 4-1) in the Local position.
The power supply is shipped with the switch in this position.
Series 657xA Supplies
Local sensing is obtained by connecting the -fLS sense terminal to the +S analog connector
pin and the pin and the -LS sense terminal to the -S analog connector pin. The power supply
is shipped with these connections made.
4-6 User Connections and Considerations
Local Voltage Sensing