Aim-TTI CPX400S, Instruction Manual

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Overvoltage protection (OVP) is fully variable within the range 1V to 66V. For
CPX400S and CPX400SP in Local mode the OVP limit is set via the screwdriver
adjustable OVP preset potentiometer, accessible through a hole in the front panel
immediately above the OVP key. Rotating the preset clockwise increases the limit,
which can be read directly on the user display by pressing the OVP key beneath the
preset. When in remote control mode (CPX400SP only) an independent OVP value
is used which is set via the RS232, USB, LAN (LXI) or GPIB interfaces (default value
66V); see the Remote Command section for further details. If the voltage on the
output exceeds the set OVP for any reason, including an externally forced voltage,
the output will be tripped off.
It should be noted that the unit can only source current and cannot sink it, thus units cannot be
series connected in anti-phase.
The unit can be connected in parallel with others to produce higher currents. Where several units
are connected in parallel, the output voltage will be equal to that of the unit with the highest output
voltage setting until the current drawn exceeds its current limit setting, upon which the output will
fall to that of the next highest setting, and so on. In constant current mode, units can be connected
in parallel to provide a current equal to the sum of the current limit settings. For optimum operation
connect the power supplies separately to the load.
Note that the output terminals are rated at 30A maximum; if two or more outputs are operated in
parallel to source higher currents than this the junction should be made at a separate point, not
one of the terminals.
Protection
OVP
Over-current protection (OCP) is implemented in firmware and can only be set and used when
under remote control via the RS232, USB, LAN (LXI) or GPIB interfaces (CPX400SP only).
Setting resolution is 10mA and typical response times are 500ms. In local mode, and for
CPX400S/SA, OCP is still active but automatically defaults to 22 Amps.
When the output is tripped the displays will show
OUP triP
. and the OUTPUT lamp will flash.
Turn the output off; the trip message should be replaced with the normal preset V and I readings.
When the cause of the trip has been removed the output can be switched on again.
Even with the output off the load is still connected to the power supply output stage. Do not apply
external voltages in excess of 70V to the power supply terminals or damage may result.
The output is protected from reverse voltages by a diode; the continuous reverse current must not
exceed 3 Amps, although transients can be much higher.
Over-temperature Protection
A sensor on the secondary heatsink will detect over-temperature due to blocked air-flow, fan failure
or other circuit fault. Over-temperature will turn the output off, the OUTPUT indicator will flash, and
the display will show the message
OtP trip . The output will remain shut down even after the
heatsink has cooled down. When the cause of the over-temperature has been removed and the
heatsink has cooled to normal working temperatures the output can be reset by turning the
POWER switch to off (
), then on ( I ) again.
View Settings
Lock Settings
Pressing the LOCK key digitally locks the set voltage and current limit. The settings are stored with
a precision of better than 1 digit. Subsequent adjustments of the VOLTAGE and CURRENT
controls will have no effect.
The set voltage and current limit are always shown when the
output is off but can also be viewed when the output is on by
pressing the VIEW key; the VIEW lamp is lit whilst the VIEW key
is pressed.