
1
Introduction
The EX2020R is an exceptionally compact and lightweight single output laboratory dc power
supply providing 0 to 20V at 0 to 20A.
The EX2020R uses mixedmode regulation technology which combines switchmode
preregulation with linear postregulation. Special techniques are used to maintain very high
efficiency whilst achieving noise levels that are close to that of a pure linear regulator.
Excellent line and load regulation are matched by low noise and good transient response. High
resolution controls allow accurate setting of voltage and current levels. Remote sense terminals
are provided so that good regulation can be maintained across remote loads at high currents.
The output operates in constant voltage or constant current mode with automatic cross-over and
mode indication. There is a DC output onoff switch.
The EX series incorporates separate digital voltage and current meters on each output. The
meters use bright 14mm (0.56”) LED displays and have an update rate of 4 per second providing
near instantaneous response. Simultaneous metering of voltage and current provides accurate
information “at a glance” and avoids any possibility of misinterpretation. When the output switch
is set to “off”, the current limit setting is displayed enabling conditions to be set before the load is
connected.
The EX series has been designed to meet the stringent requirements of the latest relevant IEC
standards for safety and EMC, including harmonics emissions. All outputs are intrinsically short
circuit proof, and are protected against external voltages and reverse currents.
Table of Contents
Introduction 1
Table of Contents 1
Specification 2
Safety 3
Installation 4
Connections 4
Operation 5
Maintenance 6
Instructions en Francais 7
Bedienungsanleitung auf Deutsch 11
Istruzioni in Italiano 16
Instrucciones en Español 21

By coarse and fine controls.
By single logarithmic control.
Constant voltage or constant current with automatic cross-over.
Electronic. Preset voltage and current displayed when off.
Universal 4mm safety binding posts on 19mm (0.75”) pitch.
Switchable between local and remote. Spring-loaded push
terminals for remote connection.
Output will withstand up to 25V forward voltage.
Reverse protection by diode clamp for reverse currents up to 3A.
Over-temperature
Protection:
The output will be tripped off if a fault causes the internal
temperature to rise excessively.
Change in output for a 10% line change:
Constant voltage: <0.01% + 2mV
Constant current: <0.01% + 2mA
Change in output for any load change, remote sense connected:
Constant voltage: <0.01% + 5mV
Constant current: <0.05% + 2mA
Ripple & Noise
(20MHz bandwidth):
Typically <2mVrms, <20mV pk-pk, constant voltage mode.
Transient Response:
<0.5ms to within 50mV of set level for a 5% to 95% load change.
Output on lamp. Constant current mode lamp.
Dual 4 digit meters with 14mm (0.56") LEDs. Reading rate 4 Hz.
Voltage 0.3% of reading ± 3digits,
Current 0.6% of reading ± 3digits
220-240VAC ±10%, 50/60Hz; 110-120VAC ± 10%, 50/60Hz by
factory option. Installation Category II.
+5ºC to +40ºC, 20% to 80% RH.
Indoor use at altitudes up to 2000m, Pollution Degree 2.
Complies with EN61010-1 & EN61326-1.
For details, request the EU Declaration of Conformity for this
instrument via http://www.aimtti.com/support (serial no. needed).
140 x 160 x 320mm (WxHxD), 3.6kg.

3
Safety
This power supply is a Safety Class I instrument according to IEC classification and has been
designed to meet the requirements of EN61010-1 (Safety Requirements for Electrical Equipment
for Measurement, Control and Laboratory Use). It is an Installation Category II instrument
intended for operation from a normal single phase supply.
This instrument has been tested in accordance with EN61010-1 and has been supplied in a safe
condition. This instruction manual contains some information and warnings which have to be
followed by the user to ensure safe operation and to retain the instrument in a safe condition.
This instrument has been designed for indoor use in a Pollution Degree 2 environment in the
temperature range 5C to 40C, 20% - 80% RH (non-condensing). It may occasionally be
subjected to temperatures between +5° and -10°C without degradation of its safety. Do not
operate while condensation is present.
Use of this instrument in a manner not specified by these instructions may impair the safety
protection provided. Do not operate the instrument outside its rated supply voltages or
environmental range.
WARNING! THIS INSTRUMENT MUST BE EARTHED
Any interruption of the mains earth conductor inside or outside the instrument will make the
instrument dangerous. Intentional interruption is prohibited. The protective action must not be
negated by the use of an extension cord without a protective conductor.
When the instrument is connected to its supply, terminals may be live and opening the covers or
removal of parts (except those to which access can be gained by hand) is likely to expose live
parts. The apparatus shall be disconnected from all voltage sources before it is opened for any
adjustment, replacement, maintenance or repair. Capacitors inside the power supply may still be
charged even if the power supply has been disconnected from all voltage sources but will be
safely discharged about 10 minutes after switching off power.
Any adjustment, maintenance and repair of the opened instrument under voltage shall be
avoided as far as possible and, if inevitable, shall be carried out only by a skilled person who is
aware of the hazard involved.
If the instrument is clearly defective, has been subject to mechanical damage, excessive
moisture or chemical corrosion the safety protection may be impaired and the apparatus should
be withdrawn from use and returned for checking and repair.
Make sure that only fuses with the required rated current and of the specified type are used for
replacement. The use of makeshift fuses and the short-circuiting of fuse holders is prohibited.
Do not wet the instrument when cleaning it.
The following symbols are used on the instrument and in this manual:-

4
Installation
Mains Operating Voltage
Check that the instrument operating voltage marked on the rear panel is suitable for the local
supply.
Mains Lead
Connect the instrument to the AC supply using the mains lead provided. Should a mains plug be
required for a different mains outlet socket, a suitably rated and approved mains lead set should
be used which is fitted with the required wall plug and an IEC60320 C13 connector for the
instrument end. To determine the minimum current rating of the lead-set for the intended AC
supply, refer to the power rating information on the equipment or in the Specification.
WARNING! THIS INSTRUMENT MUST BE EARTHED.
Any interruption of the mains earth conductor inside or outside the instrument will make the
instrument dangerous. Intentional interruption is prohibited.
Ventilation
The power supply is cooled by a low-speed fan which vents at the rear. Take care not to restrict
the air inlets at the side panels or the exit at the rear.
Connections
All connections are made from the front panel.
The load should be connected to the positive (red) and negative (black) terminals marked
OUTPUT.
Remote sense connections to the load, if required, are made from the positive (+) and
negative () SENSE terminals. Switch the LOCAL/REMOTE switch to REMOTE when remote
sensing is required. Switch back to LOCAL when remote sensing is not in use.
The terminal marked is connected to the chassis and safety earth ground.

5
Operation
Setting Up the Output
With the POWER switch on (l) and the output off the output voltage and current limit can be
accurately preset using the VOLTAGE and CURRENT controls; the left-hand meter shows the set
voltage and the right-hand meter shows the set maximum current.
When the output switch is switched on, the ON lamp lights; the left-hand meter now shows
the actual voltage and the right-hand meter the actual load current.
Constant Voltage
The output voltage is adjusted using the coarse and fine VOLTAGE controls; the CURRENT
control sets the maximum current that can be supplied.
Constant Current
If the load resistance is low enough such that, at the output voltage set, a current greater than
the current limit setting would flow, the power supply will automatically move into constant current
operation. The current output is adjusted by the CURRENT control and the VOLTAGE controls
set the maximum voltage that can be generated.
The CC lamp lights to show constant current mode.
Instantaneous Current Output
The current limit control can be set to limit the continuous output current to levels down to 10mA.
However, in common with all precision bench power supplies, a capacitor is connected across
the output to maintain stability and good transient response. This capacitor charges to the output
voltage and short-circuiting of the output will produce a current pulse as the capacitor discharges
which is independent of the current limit setting.
Protection
The output has intrinsic short-circuit protection and is protected from reverse voltages by a diode;
the continuous reverse current must not exceed 3 Amps, although transients can be much higher.
Connection to the Load
The load should be connected to the positive (red) and negative (black) OUTPUT terminals. Both
are fully floating and either can be connected to ground.
Remote Sensing
The unit has a very low output impedance, but this is inevitably increased by the resistance of the
connecting leads. At high currents this can result in significant differences between the indicated
source voltage and the actual load voltage (two 20m connecting leads will drop 0.2V at 5 Amps,
for instance). This problem can be minimised by using short, thick, connecting leads, but where
necessary it can be completely overcome by using the remote sense facility.
This requires the sense terminals to be connected to the output at the load instead of at the
source; insert wires into the spring-loaded SENSE terminals and connect directly to the load.
Switch the LOCAL/REMOTE switch to REMOTE. To avoid instability and transient response
problems, care must be taken to ensure good coupling between each output and sense lead.
This can be done either by twisting the leads together or by using coaxially screened cable
(sense through the inner). An electrolytic capacitor directly across the load connection point may
also be beneficial.
The voltage drop in each output lead must not exceed 0.5 Volts.
Switch the LOCAL/REMOTE switch back to LOCAL when remote sensing is not in use.

6
Series or Parallel Connection with Other Outputs
The outputs of the power supply are fully floating and may be used in series with other power
supply units to generate high DC voltages up to 300V DC.
The maximum permissible voltage between any terminal and earth ground ( ) is 300VDC.
WARNING! Such voltages are exceedingly hazardous and great care should be taken to shield
the output terminals for such use. On no account should the output terminals be touched when
the unit is switched on under such use. All connections to the terminals must be made with the
power switched off on all units.
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.
Note that the output terminals are rated at 30A maximum; if several 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.
Over-temperature Protection
Sensors on both the primary and secondary heatsinks will detect over-temperature due to
blocked air flow, fan failure or other circuit fault. Over-temperature will shut down the output (the
display will read 0 Volts and 0 Amps if the output is ON) though the output ON lamp will remain
lit. The output will remain shut down even after the heatsinks have cooled down. When the cause
of the over-temperature has been removed and the heatsinks have cooled to normal working
temperatures the output can be reset by turning the POWER switch off ( ) then on ( l ) again.
Maintenance
The Manufacturers or their agents overseas will provide repair for any unit developing a fault.
Where owner wish to undertake their own maintenance work, this should only be done by skilled
personnel in conjunction with the service manual which may be purchased directly from the
Manufacturers or their agents overseas.
Fuse
The correct fuse type is:
10 Amp 250V HBC time-lag(T), 5 x 20mm.
Note that the main function of the fuse is to make the instrument safe and limit damage in the
event of failure of one of the switching devices. If a fuse fails it is therefore very likely that the
replacement will also blow, because the supply has developed a fault; in such circumstances the
instrument will need to be returned to the manufacturer for service.
Make sure that only fuses of the required rated current and specified type are used for
replacement. The use of makeshift fuses and the short-circuiting of fuse-holders is prohibited.
To replace a fuse, first disconnect the instrument from the AC supply. Remove the 6 cover
securing screws and lift off the cover. Replace the fuse with one of the correct type and refit the
cover.
Cleaning
If the PSU requires cleaning use a cloth that is only lightly dampened with water or a mild
detergent. Polish the display window with a soft dry cloth.
WARNING! TO AVOID ELECTRIC SHOCK, OR DAMAGE TO THE PSU, NEVER ALLOW
WATER TO GET INSIDE THE CASE. TO AVOID DAMAGE TO THE CASE OR DISPLAY
WINDOW NEVER CLEAN WITH SOLVENTS.

7
Sécurité
Ce système alimentation est un instrument de classe de sécurité 1 conforme à la classification
IEC et il a été conçu pour satisfaire aux exigences de la norme EN61010-1 (Exigences de
sécurité pour les équipements électriques de mesure, de contrôle et d'utilisation en laboratoire).
Il s'agit d'un instrument de Catégorie II d'installation devant être exploité depuis une alimentation
monophasée standard.
Cet instrument a été testé conformément à la norme EN61010-1 et il a été fourni en tout état de
sécurité. Ce manuel d'instructions contient des informations et des avertissements qui doivent
être suivis par l'utilisateur afin d'assurer un fonctionnement et un état en toute sécurité.
Cet instrument a été conçu pour être utilisé en intérieur, en environnement de pollution de
deuxième degré (Pollution degree 2) à des plages de températures de 5C à 40C, et à des taux
d'humidité compris entre 20% et 80% (sans condensation). Il peut être soumis de temps à autre
à des températures comprises entre +5°C et –10°C sans dégradation de sa sécurité. Ne pas
l'utiliser en conditions de condensation.
Toute utilisation de cet instrument de manière non spécifiée par ces instructions risque d'affecter
sa protection de sécurité. Ne pas utiliser l'instrument hors des plages de tension d'alimentation
nominale recommandées ni hors de ses tolérances d'environnement.
AVERTISSEMENT ! CET INSTRUMENT DOIT ETRE RELIE A LA TERRE
Toute interruption du conducteur de la terre du secteur à l'intérieur ou à l'extérieur de l'instrument
rendra l'instrument dangereux. Il est absolument interdit de priver intentionnellement l'instrument
de son branchement à la terre. La sécurité de l'instrument ne doit pas être annulée par
l'utilisation de rallonge sans conducteur de protection.
Lorsque l'instrument est relié au secteur, il est possible que les bornes soient sous tension :
l'ouverture des couvercles ou la dépose de pièces (à l'exception des pièces accessibles
manuellement) risque de mettre à découvert des pièces sous tension. L'instrument doit être
débranché du secteur et de toute source d'alimentationavant tout réglage, remplacement,
travaux d'entretien ou de réparations.
Les condensateurs qui se trouvent dans le bloc d'alimentation risquent de rester chargés, même
si le bloc d'alimentation a été déconnecté de toutes les sources d'alimentation, mais ils se
déchargeront en toute sécurité environ 10 minutes après extinction de l'alimentation.
Eviter dans la mesure du possible d'effectuer des réglages, travaux de réparations ou d'entretien
lorsque l'instrument ouvert est branché au secteur. Si cela s'avère toutefois indispensable, seul
un technicien compétent connaissant les risques encourus doit effectuer ce genre de travaux.
S'il est évident que l'instrument est défectueux, qu'il a été soumis à des dégâts mécaniques, à
une humidité excessive ou à une corrosion chimique, la protection de sécurité est affaiblie :
l'instrument doit être retiré de l'exploitation et renvoyé vérifications et de réparations.
Ne remplacer les fusibles que par des fusibles d'intensité nominale requise et du type spécifié. Il
est interdit d'utiliser des fusibles "maison" et de court-circuiter des porte-fusibles.
Ne jamais humidifier l'instrument lors du nettoyage.
Les symboles suivants se trouvent sur l'instrument, ainsi que dans ce manuel.
alimentation secteur ON (allumée)
alimentation secteur OFF (éteinte)
courant alternatif (c.a.)

8
Installation
Tension d’utilisation secteur
Vérifier que la tension opérationnelle de l'instrument indiquée sur le panneau arrière est
appropriée pour l'alimentation locale.
Câble secteur
Branchez cet instrument sur l’alimentation secteur en utilisant le câble d’alimentation fourni. Si la
prise murale requiert l’utilisation d’un câble d’alimentation différent, un câble approprié et
approuvé, qui possède une fiche correspondante à la prise murale et un connecteur d’instrument
IEC60320 C13, doit être utilisé. Pour vérifier la tension nominale du câble d’alimentation en
fonction de la prise secteur, consultez les informations de puissance nominale sur l’équipement
ou dans Caractérstiques.
AVERTISSEMENT! CET INSTRUMENT DOIT ETRE RELIE A LA TERRE
Toute interruption du conducteur de terre secteur à l'intérieur ou à l'extérieur de l'instrument
rendra l'instrument dangereux. Il est absolument interdit d'effectuer une interruption à dessein.
Ventilation
L'unité d'alimentation est refroidie par un ventilateur à faible vitesse de rotation qui aère l'arrière.
Prendre soin de ne jamais obstruer les fentes d'aération des panneaux latéraux ni l'arrière de
l'unité
Connexions
Toutes les connexions sont effectuées au panneau avant.
Relier la charge aux bornes positive (rouge) et négative (noire) marquées OUTPUT (Sortie).
Effectuer des connexions de télédétection à la charge, le cas échéant, des bornes de détection
(SENSE) positive (+) et négative (). Placer le commutateur LOCAL/REMOTE en position
REMOTE lorsque la détection distante est requise. Placer le commutateur en position LOCAL
lorsque cette détection distante n’est pas utilisée.
La borne désignée est reliée au châssis et à la terre de protection.