Agilent Technologies 6641A, Operating Manual, Page: 74 / 142

User Connections 74
Auto-Parallel Programming. Program only the output current of the first ("master") supply in the series; the "slave"
supplies automatically track the master's output. Program the output current of the slave supplies to zero. However, the
voltage and OVP settings of the slave supplies must be set higher than the operating voltage of the master supply. This
ensures that the slave supplies will operate in CC mode. Functions such as status, voltage readback, and current readback
can still be read back individually for each supply.
If a "slave" supply experiences a desired shutdown condition (such as overtemperature or overcurrent), it will not
automatically shut down all other supplies. You must first enable remote inhibit (RI) and discrete fault indicator (DFI)
operation. See "Fault/Inhibit Operation" in "Appendix D - Digital Port Functions" for wiring information and "Questionable
Status Group" in Chapter 4 of the "Programming Guide" for programming information.
Connecting Supplies in Series
Floating voltages must not exceed 240 Vdc. No output terminal may be more than 240 V from chassis
ground.
Figure 4-4f shows how power supplies can be connected in series for higher voltage output. Series connections are
straightforward in this case.
Program each power supply independently. If two supplies are used in the series configuration, program each supply for
50% of the total output voltage. Set the current limit of each supply to the maximum that the load can handle without
damage.
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 Table 1-2b).
Load Connection Analog Connector Load
Program each supply for full load current and 1/2 the load voltage
A Connect for remote sensing (optional)
WARNING
FLOATING VOLTAGES MUST NOT EXCEED ± 240 VDC NO OUTPUT TERMINAL MAY
BE MORE THAN 240 V FROM CHASSIS GROUND.
Figure 4-4f. Series 667xA Series Connection (Remote Sensing Optional)