Section 3 - Operating Instructions; Operating Configuration; Remote Error Sense; Output Voltage Programming - KEPCO HSM 3.3-230 Operator's Manual

3.1

OPERATING CONFIGURATION

The following subsections review the various features and indicate how to select and operate
each function. The default settings for each function indicate the as-shipped status for standard
HSM series power supplies. Prior to applying source power, the operating configuration of the
HSM power supply must be selected. This setup is performed via the multiposition configura-
tion switches S1, S2 and S3 which are accessed via slots in the top cover (see Figure 2-1),
while the external control signals (programming input and status output) are accessed via the
I/O Connector on the rear panel of the HSM power supply (see Figure 2-2).
HSM series power supplies incorporate several advanced features which expand their applica-
bility beyond that of simple voltage stabilizers. These functions include both internal and exter-
nal programming of voltage and current regulation points, remote error sensing, active load
sharing circuitry, output overvoltage and undervoltage protection, output current "walk-in," in-cir-
cuit voltage and current setpoint monitors, and dual-mode floating inhibit controls, as well as
Form-C relay contact outputs indicating source, output and fan status, and overtemperature
shutdown.
3.2

REMOTE ERROR SENSE

All HSM power supplies are equipped with remote error sensing to compensate for the voltage
drop inherent in any power supply/load interconnection scheme. The amount of compensation
varies based on output voltage: 3.3V and 5V models compensate up to 0.25V drop in each
power lead (0.5V total), while 12V through 48V models provide for up to 0.8V drop in each lead
(1.6V total). The remote error sense leads must be connected to the output power termi-
nations, either locally at the power supply output terminals or remotely at the load termi-
nations, using the correct polarity, for the HSM to operate properly. (See Figures 2-3
through 2-6.)
3.3

OUTPUT VOLTAGE PROGRAMMING

HSM power supplies provide three different methods for programming the output voltage regu-
lation point: internal, external resistance and external voltage. When using either internal or
external resistance programming, the minimum programmable voltage is 50-60% of nominal,
while external voltage programming permits adjustment down to zero. Performance specifica-
tions are only guaranteed over the range shown in Table 1-1. The programming method is
selected via S2 switch positions 3, 4 and 5 as follows:
NOTE: One programming mode must be selected, or the HSM output voltage programs to
zero; never select more than one programming mode at a time.
a) Internal Programming: This is the factory-set (default) mode (see Figure 2-1); when
enabled via S2-5, the output voltage is adjusted via the internal potentiometer labeled "V
(see Figure 2-1).
b) External Resistance Programming: When enabled via S2-4, this mode provides for output
voltage adjustment via an external resistance or potentiometer (0-50Kohm) connected
between pins 17 and 35 (VRP1, VRP2) of the I/O connector (see Figure 3-1). This technique
is useful for applications where the voltage output of the power supply must be locked to a
preset value without means of adjustment (security), or where the voltage output of the
power supply must be remotely adjusted after installation (convenience).
HSMSERIES OPR 052912

SECTION 3 - OPERATING INSTRUCTIONS

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