RS PRO Iso-tech IPS 303A User manual

SAFETY TERMS AND SYMBOLS
These terms may appear in this manual or on the product:
WARNING. Warning statements identify conditions or practices that
could result in injury or loss of life.
CAUTION. Caution statements identify conditions or practices that could
result in damage to this product or other property.
The following symbols may appear in this manual or on the product:
DANGER
High Voltage
DANGER
Hot Surface ATTENTION refer to Manual Protective Conductor
Terminal
Equipotentiality
DC POWER SUPPLY
ALIMENTATION C.C.
ISO-TECH IPS 303A 201-3424
ISO-TECH IPS 601A 201-3446

Statement of Compliance
IPS 303A & IPS 601A Power Supply
is herewith confirmed to comply with the requirements set out in the Council Directive on the Approximation of the Law of
Member States relating to Electromagnetic Compatibility (89/366/EEC, 92/31/EEC, 93/68/EEC) and Low Voltage Equipment
Directive (73/23/EEC). For the evaluation regarding the Electromagnetic Compatibility and Low Voltage Equipment Directive,
the following standards were applied:
EMC Directive 89/366/EEC amended by 92/31/EEC; 93/68/EEC
EN 50081-1 (1992):
Electromagnetic Compatibility- Generic Emission Standard.
Part 1: Residential, Commercial and Light Industry
EN 50082-1 (1992):
Electromagnetic Compatibility- Generic Immunity
Standard.
Part 1: Residential, Commercial and Light Industry
Conducted and Radiated Emissions
EN 55022 class B (1994) Electrostatic Discharge IEC 1000-4-2: 1995
Current Harmonic
EN 61000-3-2 (1995) Radiated Immunity IEC 1000-4-3: 1995
Voltage Fluctuation
EN 61000-3-3 (1995) Electrical Fast Transients IEC 1000-4-4: 1995
Surge Immunity
IEC 1000-4-5: 1995
Voltage Dips / Interrupts
EN 61000-4-11: 1994
Low Voltage Equipment Directive 73/23/EEC
Safety Requirements
EN 61010-1: 1993+A2: 1995
IEC 1010-1 : 1990+A2: 1995
FOR UNITED KINGDOM ONLY
NOTE
This lead/appliance must only
be wired by competent persons
WARNING
THIS APPLIANCE MUST BE
EARTHED
IMPORTANT
The wires in this lead are
coloured in accordance with
the following code:
Green/
Yellow: Earth
Blue : Neutral
Brown: Live (Phase)
As the colours of the wires in main leads may not correspond with the colours marking
Identified in your plug/appliance, proceed as follows:
The wire which is coloured Green & Yellow must be connected to the Earth terminal
marked with the letter E or by the earth symbol or coloured Green or Green &
Yellow.
The wire which is coloured Blue must be connected to the terminal which is marked with
the letter N or coloured Blue or Black.
The wire which is coloured Brown must be connected to the terminal marked with the
letter L or P or coloured Brown or Red.
If in doubt, consult the instructions provided with the equipment or contact the supplier.
This cable/appliance should be protected by a suitably rated and approved HBC mains
fuse; refer to the rating information on the equipment and/or user instructions for details.
As a guide, cable of 0.75mm ²should be protected by a 3A or 5A fuse. Larger
conductors would normally require 13A types, depending on the connection method
used.
Any moulded mains connector that requires removal/replacement must be destroyed by
removal of any fuse & fuse carrier and disposed of immediately, as a plug with bared
wires is hazardous if a engaged in live socket. Any re-wiring must be carried out in
accordance with the information detailed on this label.

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CONTENTS
SECTION PAGE
1. INTRODUCTION…………………………………………………………………………….……………………… 1
2. SPECIFICATIONS…………………………………………………………………………………………………... 2
2-1 General…………………………………………………………………………………….…………………..….2
2-2 Constant Voltage Operation………………………………………………………………………..…………… 2
2-3 Constant Current Operation………………………………………………………………………..…………... 3
2-4 Indicator Meter………………………………………………………………………………………..………….3
2-5 Insulation………………………………………………………………………………………………………….3
3. PANEL CONTROLS AND INDICATORS………………………………………………………………………… 4
3-1 Front Panel…………………………………………………………………………………………..……………4
3-2 Rear Panel………………………………………………………………………………….…………………….. 4
4. OPERATION INSTRUCTIONS………………………………………………………………………..…………… 7
4-1 Precaution………………………………………………………………………………….…………………….. 7
4-2 Setting Current Limit………………………………………………………………………………………….…7
4-3 Constant Voltage/Constant Current Characteristic………………………………………………….……….. 7
4-4 Operation Mode………………………………………………………………………………………..…………9
5. MAINTENANCE…………………………………………………………………………………………..………….15
5-1 Fuse Replacement…………………………………………………………………………………………….….. 15
5-2 Line Voltage Conversion………………………………………………………………………………………....15
5-3 Internal Adjustments………………………………………………………………………………………….…15
5-4 Cleaning……………………………………………………………………………………………………….…..16

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1. INTRODUCTION
The regulated DC power supply has been designed to provide the most often used features in the laboratory,
schools and production lines.
The output voltage is continuously adjustable between 0 and rated voltage in one range by means of a coarse and
fine potentiometer; the load current can be varied from 0 to rated current and adjusted by means of a coarse and fine
potentiometer. Both outputs can be accurately read on the voltmeter and ammeter.
Both stability and ripple are extremely good to meet the requirements of modern circuit design. The unit can be
used as either constant voltage or current source. The various modes of operation are described in greater detail in
Operation Instruction Section 4 of this manual.
For applications which use greater than the maximum voltage or Amps, then the unit can be connected up in
series or parallel. For applications in audio production lines, continuous or dynamic load.

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2. SPECIFICATIONS
2-1 General
Main supply : 100V/120V/220V/230V±10% 50/60Hz (Switch selectable).
Rating, dimension and weight : see Table 2-1
Operation mode : Single or Tracking (Series or Parallel) operation (two units).
Operation Temperature & Humidity : 0ºC to 40ºC, <80%
Storage Temperature & Humidity : -10ºC to 70ºC, <70%
Maximum Altitude : 2000m
Installation Category : II
Pollution Degree : 2
Product Designed for Indoor use only
Accessories : Fuse……………………………………………………………..1
: Test lead GTL-105 (current <4A)…………………..……….….1
GTL-104 (4A∗current∗10A)
: Operation Manual………………………………………..……...1
Table 2-1 Max. Rating Input Rating FUSE Type and Rating Dimensions Weight
MODEL Volts (V) Amps (A) Watts VA 100V/120V 220V/230V (kg)
IPS 303A 30 3 160 200 T 2.5A 250V T 1.6A 250V 5.0
IPS 601A 60 1 120 150 T 2A 250V T 1.6A 250V
128 (W)
145 (H)
285 (D) 4.0

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2-
2 Constant Voltage Operation
(1) Output voltage ranges 0 to rating voltage continuously adjustable.
(2) Voltage regulation
line regulation ∗0.01%+3mV.
load regulation ∗0.01%+3mV (rating current ∗3A).
load regulation ∗0.01%+5mV (rating current >3A).
(3) Recovery time ∗100µs (50% Load change, minimum load 0.5A).
(4) Ripple & Noise ∗0.5mVrms (5Hz~1MHz) (rating current ∗3A).
Ripple & Noise ∗1.0mVrms (5Hz~1MHz) (rating current >3A).
(5) Temperature coefficient ∗300ppm/ºC.
2-3 Constant Current Operation
(1) Output current range 0 to rating current continuously adjustable.
(2) Current regulation
line regulation ∗0.2%+3mA.
load regulation ∗0.2%+3mA.
(3) Ripple & Noise∗3mArms.
2-4 Indicator Meter
Analog
Meter : Voltmeter and Ammeter each one
Class : 2.5.
Dimensions : 50×50 m/m.
2-5 Insulation
Between chassis and output terminal : 20MO or above (DC500V).
Between chassis and AC cord : 30MOor above (DC500V).

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3. PANEL CONTROLS AND INDICATORS
3-1 Front panel (See Fig. 3-1)
(1) CV Indicator lights when the power is on and this unit is in constant voltage operation.
(2) CC Indicator lights when this unit is in constant current operation.
(3) Voltage coarse for the coarse adjustment of the output voltage.
(4) Voltage fine for the fine adjustment of the output voltage.
(5) Current coarse for the coarse adjustment of the output current.
(6) Current fine for the fine adjustment of the output current.
(7) “+” output terminal positive polarity (Red).
(8) “GND” terminal earth and chassis ground (Green).
(9) “–” output terminal negative polarity (Black).
(10) meter indicates the output voltage (Analog type).
(11) meter indicates the output current (Analog type).
(12) A/V selects switch selects whether he meter indicates the output voltage or current.
(13) Power control on/off switch.
(14) Current HI/LO control current indicates HI/LO range SELECTS.
3-2 Rear panel (See Fig. 3-2)
(15) Fuse holder
(16) Power cord
(17) AC selects switch With (18) switch selects the line voltage at the high end (right position) of the
range 120V or 230V and at the low end (left position) of the range 100V or 220V.
(18) AC selects switch Selects the line voltage is in the 100V-120V range (left position) or in the
220V-230V in the range (right position).
(19) Master-Slave switch Selects for Master (internal control) or Slave (external remote control) tracking
operation.
(20) Input-Output connector With (19) Master-Slave switch selects, permit from the Master unit (SER. or
PAR.) output connected to Slave unit (SER. or PAR.) inputs.

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FIG. 3-1 Front Panel

E6
FIG. 3-2 Rear Panel

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4. OPERATION INSTRUCTIONS
4-1 Precaution
(1) AC input
AC input should be within the range of line voltage ±10% 50/60Hz.
WARNING. To avoid electrical shock, the power cord protective grounding conductor must be connected
to ground.
(2) Installation
Avoid using the power supply in a place where the ambient temperature exceeds 40ºC. The heat sink located at the rear
of the power supply must have sufficient air space for radiation.
CAUTION. To avoid damaging the power supply, do not use it in a place where ambient temperature exceeds 40ºC.
(3) Output voltage overshoot
Voltage between output terminals never exceeds the preset value when the power is turned on or off.
4-2 Setting Current Limit
(1) Determine the maximum safe current for the device to be powered.
(2) Temporarily short the (+) and (-) terminals of the power supply together with a test lead.
(3) Rotate the COARSE VOLTAGE control away from zero sufficiently for the CC indicator to light.
(4) Adjust the CURRENT control for the desired current limit. Read the current value on the Ammeter.
(5) The current limit (overload protection) has now been preset. Do not change the CURRENT control setting after this
step.
(6) Remove the short between the (+) and (-) terminals and hook up for constant voltage operation.
4-3 Constant Voltage / Constant Current Characteristic
The working characteristic of this series Power Supplies is called a constant voltage/constant current automatic crossover
type. This permits continuous transition from constant current to constant voltage modes in response to the load change.
The intersection of constant voltage and constant current modes is called the crossover point. Fig. 4-1 shows the
relationship between this crossover point and the load.
For example, if the load is such that the power supply is operating in the constant voltage mode, a regulated output voltage
is provided. The output voltage remains constant as the load increases, up until the point where the preset current limit is
reached. At that point, the output current becomes constant and the output voltage drop is proportional to further increases
in load. The crossover point is indicated by the front panel LED indicators. The crossover point is reached when the CV

E8
indicator goes off and the CC indicator comes on.
Fig. 4-1 Constant Voltage/Constant Current Characteristic
Similarly, crossover from the constant current to the constant voltage mode automatically occurs from a decrease in load. A
good example of this would be seen when charging a 12-volt battery. Initially, the open circuit voltage of the power supply may
be preset for 13.8 volts. A low battery will place a heavy load on the supply and it will operate in the constant current mode,
which may be adjusted for a 1 amp charging rate. As the battery becomes charged, and its voltage approaches 13.8 volts, its
load decreases to the point where it no longer demands the full 1 amp charging rate. This is the crossover point where the power
supply goes into the constant voltage mode.

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4-
4 Operation Mode
(1) Single Operation
Use the supply as it is for single operation.
A. Set power switch to “OFF” position.
B. Make sure that line voltage is correct for the input power voltage.
C. Plug power cord into the power outlet.
D. Set power switch to “ON” position.
E. Adjust “Voltage” and “Current” control to the desired output voltage and current.
F. Connect the external load to the output binding posts. Make sure both “+” and “” terminals are connected
correctly.
(2) Series Operation (only applies when using identical models)
Two power supplies can be connected in series to provide a higher voltage and rating current output. See Fig. 4-2 for
the connection scheme.
A. Set power switch to “OFF” position.
B. Set the “MASTER” power supply INT-SLAVE switch to “INT” position and set the “SLAVE” power supply
INT-SLAVE switch to “SER-SLAVE” position.
C. Connect the “MASTER” power supply “SER” output terminal to the “SLAVE” power supply “SER” input.
D. Set power switch to “ON” position.
WARNING: Voltages of more than 60V DC are a lethal shock hazard to the user. Be
careful when connecting power supplies in series to achieve voltages higher than 60V DC
total or 60V DC between any connection and earth ground.

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Fig. 4-2 Connecting Two Power Supplies in Series

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E. When connected in series, the VOLTAGE controls of each power exercise control supply over 0 to rating range.
Add the two voltmeter readings together to determine the total output voltage, or an external voltmeter may be
connected across the load.
F. Load current may be monitored from either supply; the readings will be identical since they are connected in
series. Also, since the supplies are connected in series, it is only necessary to set the current limit on one of the
supplies; the other may be set for maximum.
(3) Parallel Operation
Two power supplies may be connected in parallel to provide rating voltage and higher current output. See Fig. 4-3 for
the connection scheme.
A. Set power switch to "OFF" position.
B. Set the “MASTER” power supply INT-SLAVE switch to “INT” position and set the “SLAVE” power supply
INT-SLAVE switch to “PAR-SLAVE” position.
C. Create a link from the “MASTER” power supply “PAR” output terminal to the “SLAVE” power supply “PAR”
input.
D. When connected in parallel ensure that the SLAVE VOLTAGE and CURRENT controls are set to maximum, then
adjust the MASTER controls to set the required VOLTAGE and CURRENT.
E. The output voltage may be monitored from either supply; the readings will be identical since they are connected in
parallel, however the total output current can be determined by adding the two ammeter readings together, or an
external ammeter may be connected in series with the load.
F. Set the power switches to “ON” position.
G. Note: For correct operation ensure the MASTER output voltage is lower than 0.2-0.5V of the SLAVE output
voltage.

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Fig. 4-3 Connecting Two Power Supplies in Parallel

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(4) Remote control of output voltage
The output voltage of the power supply can be remote-controlled with an external voltage; the connection required is
shown in Fig. 4-4.
lFig. 4-4
A. Set the power supply INT-SLAVE switch to “SER-SLAVE” position.
B. The “+” line of control voltage source is connected to the “SER” input terminal and the “-” line of control
voltage source is connected to the power supply output “+” terminal.
C. The output voltage Eo is calculated as follows:
Eo: Output voltage of the power supply.
Er: Rated voltage of the power supply.
Ec: Remote control voltage.
0 ∗Ec ∗approx.10V.
D. For the remote voltage source Ec, use a device which provides a stable, low-noise voltage source
(an RS IPS series power supply or an equivalent device).
10
EcEr
Eo
×
=

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(5) Remote control of output current
The output current of the power supply can be remote-controlled with an external voltage; the connection required
is shown in Fig. 4-5.
lFig. 4-5
A. Set the power supply INT-SLAVE switch to “PAR-SLAVE” position.
B. The “-” line of control voltage source is connected to the “PAR” input terminal and the “+” line of control
voltage source is connected to the power supply output “+” terminal.
C. The output current Io is calculated as follows:
Io: Output current of the power supply.
Ir: Rated current of the power supply.
Ec: Remote control voltage.
0 ∗Ec∗approx.10V.
D. For the remote control voltage source Ec, use a device which provides a stable, low-noise voltage source (an RS
IPS series power supply or an equivalent device).
(6) Dynamic Load Operation & Application:
A. When selecting the dynamic load function, the maximum peak current is 1.7 times the rated current. These
features are only suitable for the testing of Audio circuitry.
Please change jump wire J108 to the “ON” position (please refer to Fig. 5-1).
10
EcIr
Io
×
=

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5. MAINTENANCE
The following instructions are for use by qualified personnel only. To avoid electrical shock, do not perform any
servicing other than contained in the operating instructions unless you are qualified to do so.
5-1 Fuse Replacement
If the fuse is blown, the CV or CC indicators will not light and the power supply will not operate. The fuse should not
normally blow unless a problem has developed in the unit. Try to determine and correct cause of the blown fuse, then
replace only with a fuse of the correct rating and type.
The fuse is located on the rear panel (see Fig. 3-2).
WARNING: For continued fire protection. Replace fuse only with 250V fuse of the specified type
and rating, and disconnect the power cord before replacing fuse.
5-2 Line Voltage Conversion
The primary winding of the power transformer is tapped to permit operation from 100, 120, 220, or 230 VAC, 50/60
Hz line voltage. Conversion from one line voltage to another is done by changing AC selects switch as shown in Fig. 3-
2.
The unit is set to default line voltage. To convert to different line voltage, perform the following procedure:
(1) Make sure the power cord is unplugged.
(2) Change the AC selects switch to the desired line voltage position.
(3) A change in line voltage may also require a corresponding change of fuse value. Install the correct fuse value as
listed on rear panel.
5-3 Internal Adjustments
The unit was accurately adjusted at the factory before shipment. Readjustment is recommended only if repairs have
been made in a circuit affecting adjustment accuracy, or if you have a reason to believe the unit is out of accuracy.
However, adjustments should be attempted only if a multimeter with an accuracy of ±0.1% dcv or better is available.
WARNING

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If readjustment is required, use the following procedure. Locations of the adjustments are shown in Fig. 5-1 and Fig. 5-
2.
(1) Adjustment of the Rating Voltage
A. Connect an accurate (±0.1%) external multimeter to measure the DC voltage at output terminals of the power
supply.
B. Set the COARSE and FINE VOLTAGE controls to minimum (fully counterclockwise).
C. Adjust trimmer pot VR106 for a reading of 0 volts on the multimeter.
D. Turn the COARSE and FINE VOLTAGE controls to maximum (fully clockwise).
E. Adjust trimmer pot VR105 for a reading of rate volts × 1.05 on the multimeter.
F. Set the COARSE and FINE VOLTAGE controls for a reading of rate volts on the multimeter.
G. Adjust trimmer pot VR301 (VR201 digital type) for a reading of rate volts on the voltmeter (Digital panel
meter, digital type) of the power supply.
(2) Adjustment of the Rating Current
A. Set the CURRENT control to minimum (fully counterclockwise).
B. Connect the external multimeter to measure DC current at the output terminals of the power supply.
C. Set the COARSE and FINE CURRENT controls to minimum (fully counterclockwise).
D. Adjust trimmer pot VR107 for a reading of 0 amps on the multimeter.
E. Set the COARSE and FINE VOLTAGE controls to a centered position.
F. Set the COARSE and FINE CURRENT controls to maximum (fully clockwise).
G. Adjust trimmer pot VR108 for a reading of 1/2 rate amps × 1.05 on the multimeter (LO current).
H. Adjust trimmer pot VR109 for a reading of rate amps × 1.05 on the multimeter (HI current).
I. Readjust the CURRENT control for a reading of rate amps on the multimeter.
J. Adjust trimmer pot VR110 (HI), VR111 (LO) to calibrate the Ammeter or Digital panel meter of the power
supply for the same reading as the multimeter.
5-4 Cleaning
To clean the power supply, use a soft cloth dampened in a solution of mild detergent and water. Do not spray cleaner
directly onto the instrument, since it may leak into the cabinet and cause damage. Do not use chemicals containing
benzine, benzene, toluene, xylene, acetone, or similar solvents. Do not use abrasive cleaners on any portion of the
power supply.

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Fig. 5-1 Adjustment Location