Remote Voltage Sensing; Setting Up Remote Sense Operation; Connecting The Sense Leads - HP 654 A Series Operating Manual

Note If the sense terminals are left unconnected, the voltage at the bus bars will
increase approximately 3 to 5 % over the programmed value. Since it is
measured at the sense terminals, the voltage readback will not reflect this
increased output.
REMOTE VOLTAGE SENSING
The dashed lines in Figure 4-4 illustrate a typical power supply setup using remote voltage
sensing. In this case, the remote sense terminals of the power supply are connected directly
to the load rather than to the output terminals. This allows the supply to automatically
compensate for the voltage drop in the load leads as well as to accurately read back the
voltage directly across the load.
Setting Up Remote Sense Operation
Series Series 654xA and 655xA Supplies
Remote sensing is obtained by placing the SENSE switch (see Figure 4-1) in the Lemote
position. The power supply is shipped with the switch in the Local position.
Series 667xA Supplies
Remote sensing is obtained by removing the jumpers connecting the -l-LS sense terminal to
the -fS analog connector pin and the -LS sense terminal to the -S analog connector pin. The
power supply is shipped with these jumpers connected.
Connecting the Sense Leads
You must connect the positive side of the load to the -|-S analog connector pin and the
negative side of the load to the -S analog connector pin (see Figure 4-3). Connect the sense
leads carefully so that do not become open-circuited. If sense leads are left open during
operation, the supply will regulate at the output terminals instead of at the load. Remember
to bundle or tie wrap the load leads to minimize indectance and reduce noise pickup.
CV Regulation
The voltage load regulation specification in "Performance Specifications" applies at the output
terminals of the power supply. When remote sensing, this specification must be compensated
as follows:
Series 654xA and 655xA Supplies
Add 3 mV to the voltage load regulation specification for each 1-volt change in the positive
load lead due to a change in load current. Because the sense leads are part of the supply's
feedback path, keep the resistance of the sense leads at or below 0.5 Q. to maintain the above
specified perfomance.
Series 657xA Supplies
Add an increment to the voltage load regulation specification as specified by "AmV" in the
equation given under Load regulation in Table l-2b.
User Connections and Considerations 4-7