Ametek Elgar ReFlex Power Operation Manual page 246

ReFlex Power™
R S
EMOTE ENSE
Remote sensing is used to compensate for the voltage drop that occurs across
the wires connecting the load to the output of the DC power supply modules. A
separate pair of wires is routed to measure the voltage at the load terminals
where precise regulation of the output voltage is desired.
The remote sense leads are connected at the DC OUTPUT connector on the
front panel of the modules. Refer to the section, DC OUTPUT, for information on
connector pinout. Connect the SNS terminal to the load terminal connected to the
module OUT terminal, and the SNS-RTN terminal to the load terminal connected
to OUT-RTN terminal.
Special care is required in routing the sense leads to prevent noise pickup or
coupling from the power leads; refer to the section, NOISE AND IMPEDANCE
EFFECTS. The sense leads should be a twisted-pair of at least AWG #22 wire,
and may require shielding in high noise environments. Connect the shield to the
shield ground terminal, CHAS-GND, of the DC OUTPUT connector, as required
to maximize its effectiveness.
If the remote sense leads are not connected, the DC modules will continue to
operate but the voltage at the load will no longer be precisely regulated. An
internal resistor network exists within the module that connects the output
terminals to the remote sense terminals. This network provides the measurement
of the output voltage when the remote sense leads are not connected. However,
since the voltage is now measured at the output terminals, the voltage drop of
the load wiring would no longer be compensated.
Several conditions related to remote sensing are treated as faults and result in
shutdown of the output: short-circuiting of the remote sense terminals;
connecting the remote sense leads in reverse polarity; excessive line drop in the
load wires. When the fault condition is detected, shutdown will result with the
output voltage being programmed to zero and the output isolation relay being
opened.
M E
ODULE
The module output enable signal, ENA, of the front panel INTERFACE connector
provides an external control input for turning the output of the module on/off. This
signal is pulled up through a 10kΩ resistor to an internal 5VDC source, and is
isolated from the output terminals of the DC OUTPUT connector. A logic-low
signal (ENA to ENA-RTN at ≤ 0.8V) will turn the output on, while a logic-high
(ENA to ENA-RTN at ≥ 3.7V) will turn the output off. The module output follows
the logic state of ENA, with the output changing between 0V when off and the
programmed value when on. An 100ms delay exists between the application of
ENA (going logic-low) and the output turning on, and a 100µs delay exists
between removal of ENA (going logic-high) and the output turning off. The ENA
M380056-01 Rev L
(ENA)
NABLE
DC Power Supplies
6-43