RCF PS 6648 User manual

USER MANUAL
MANUALE D’USO
PS 6648
PS 4248
-BACKUP POWER SUPPLY UNIT
AND BATTERY CHARGER
-ALIMENTATORE D’EMERGENZA
E CARICA BATTERIE

ENGLISH
SAFETY PRECAUTIONS
DESCRIPTION
FRONT PANEL
REAR PANEL
OPERATION
INSTALLATION AND DIP-SWITCH SETTINGS
CONNECTIONS
STARTUP
SPECIFICATIONS
DIMENSIONS
MAINTENANCE
PC CONFIGURATION SOFTWARE
ITALIANO
AVVERTENZE PER LA SICUREZZA
DESCRIZIONE
PANNELLO FRONTALE
PANNELLO POSTERIORE
FUNZIONAMENTO
INSTALLAZIONE ED IMPOSTAZIONE DEI DIP-SWITCH
COLLEGAMENTI
PRIMO AVVIAMENTO
DATI TECNICI
DIMENSIONI
MANUTENZIONE
CONFIGURAZIONE DA SOFTWARE PER PC
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TABLE OF CONTENTS
INDICE

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Before connecting and using this product, please read this instruction manual carefully and
keep it on hand for future reference.
The manual is to be considered an integral part of this product and must accompany it
when it changes ownership as a reference for correct installation and use as well as for the
safety precautions.
RCF S.p.A. will not assume any responsibility for the incorrect installation and / or use of
this product.
WARNING: To prevent the risk of re or electric shock, never expose this product to rain
or humidity.
SAFETY PRECAUTIONS
1. All the precautions, in particular the safety ones, must be read with special attention, as
they provide important information.
2. POWER SUPPLY FROM MAINS
-The mains voltage is sufciently high to involve a risk of electrocution: never install or
connect this product when its power cord is plugged in.
-Before powering up, make sure that all the connections have been made correctly and
the voltage of your mains corresponds to the voltage shown on the rating plate on the
unit, if not, please contact your RCF dealer.
-The metallic parts of the unit are earthed by means of the power cord.
An apparatus with CLASS I construction shall be connected to a mains socket outlet
with a protective earthing connection.
-Protect the power cord from damage. Make sure it is positioned in a way that it
cannot be stepped on or crushed by objects.
-To prevent the risk of electric shock, never open this product: there are no parts inside
that the user needs to access.
-The mains plug is used as the disconnect device and it shall remain readily operable.
2.2 BATTERIES
-Operating voltage is 48 V dc (therefore, it is necessary to connect in series several
batteries having a lower nominal voltage, example: 4 x 12 V).
-Always use rechargeable batteries, which need to be chosen according to the
maximum possible load.
-Verify the polarity of batteries is correct.
-Do NOT short-circuit batteries (i.e. connecting the 2 opposite poles together with
metallic wires).
-Throw empty batteries away according to your country laws about ecology and
environment protection.
3. Make sure that no objects or liquids can get into this product, as this may cause a short
circuit.
This apparatus shall not be exposed to dripping or splashing.
No objects lled with liquid (such as vases) and no naked sources (such as lighted candles)
shall be placed on this apparatus.
4. Never attempt to carry out any operations, modications or repairs that are not expressly
SAFETY PRECAUTIONS
IMPORTANT
WARNING

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described in this manual.
Contact your authorized service centre or qualied personnel should any of the following
occur:
-The product does not function (or functions in an anomalous way).
-The power cord has been damaged.
-Objects or liquids have got into the unit.
-The product has been subjected to a heavy impact.
5. If this product is not used for a long period, disconnect both the power cord and batteries.
6. If this product begins emitting any strange smell or smoke, switch it off immediately and
disconnect both the power cord and batteries.
7. Do not connect this product to any equipment or accessories not foreseen.
For suspended installation, only use the dedicated anchoring points and do not try to hang
this product by using elements that are unsuitable or not specic for this purpose.
Also check the suitability of the support surface to which the product is anchored (wall,
ceiling, structure, etc.), and the components used for attachment (screw anchors, screws,
brackets not supplied by RCF etc.), which must guarantee the security of the system /
installation over time, also considering, for example, the mechanical vibrations normally
generated by transducers.
To prevent the risk of falling equipment, do not stack multiple units of this product unless
this possibility is specied in the user manual.
8. RCF S.p.A. strongly recommends this product is only installed by professional qualied
installers (or specialised rms) who can ensure correct installation and certify it according
to the regulations in force.
The entire audio system must comply with the current standards and regulations regarding
electrical systems.
9. Supports and trolleys
The equipment should be only used on trolleys or supports, where necessary, that are
recommended by the manufacturer. The equipment / support / trolley assembly must be
moved with extreme caution. Sudden stops, excessive pushing force and uneven oors may
cause the assembly to overturn.
10. Do not obstruct the ventilation grilles of the unit. Situate this product far from any heat
sources and always ensure adequate air circulation around the ventilation grilles.
11. Do not use solvents, alcohol, benzene or other volatile substances for cleaning the
external parts of this product. Use a dry cloth.

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RCF S.P.A. THANKS YOU FOR PURCHASING THIS PRODUCT, WHICH HAS BEEN
DESIGNED TO GUARANTEE RELIABILITY AND HIGH PERFORMANCES.
DESCRIPTION
PS 6648 and PS 4248 are backup power supply units suitable for EN 54-16 system devices
(e.g. DXT 9000 and DXT 7000EN, RCF voice alarm systems).
These need to be equipped with lead-acid batteries and includes recharging and monitoring
functions.
PS 6648 has six main outputs for max. 6 ampliers (one amplier per each output) and six
auxiliary outputs (for i.e. routers, paging microphones, controllers).
PS 4248 has four main outputs for max. 4 ampliers (one amplier per each output) and
two auxiliary outputs.
SUPPLIED ACCESSORIES:
-Temperature sensor, with a 1.5 m cable and a plug.
-Set of 6 plugs (PS 6648) / 4 plugs (PS 4248) to connect ampliers to outputs (‘OUT’).
-Set of 6 plugs (PS 6648) / 2 plugs (PS 4248) to connect other devices to aux outputs
(‘AUX’).
-Set of 3 plugs to connect the logic outputs (with internal relays).
-A plug to connect the external fault input (with a linking jumper).

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FRONT PANEL
1LEDs
2ST push-button
Push the ST push-button to:
-Start from batteries only (see ‘COLD START’ WITH BATTERIES ONLY in the OPERATION
manual section).
-Manually start the battery circuit resistance test (see BATTERY CIRCUIT RESISTANCE
TEST in the STARTUP manual section).
-Reset the device (see DEVICE RESET in the OPERATION manual section).
3PC CONFIG
USB port (type B) to link a PC computer
(see the PC CONFIGURATION SOFTWARE manual section).
3
3
2
2
1
1
LABEL COLOUR STATE DESCRIPTION
MAINS green
lit Mains power (230 V ac) is present.
off No mains power or rectier fault.
BATTERY yellow
lit Battery operation (due to no mains or rectier fault).
off Normal operation when the mains power is present.
CHARGING green
blinking Battery boost charge or rell.
lit Battery oat charge.
off Battery charge is completed.
FAULT yellow
blinking
External fault command activated (at Ext fault input)
Note: if during the activation of the external fault command any internal
fault occurs, the FAULT LED will be steady lit.
lit Generic Fault (see the MAINTENANCE manual section).
off Normal operation when mains power is present (no faults).

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REAR PANEL
4BATT. 48V
Two (M8 bolt / nut) input terminals to connect batteries (48 V: four 12 V batteries linked
in series).
Pay attention to the polarity: + (positive), – (negative).
5OUT 1 - 6 (PS 6648) / OUT 1 - 4 (PS 4248)
48 V outputs to connect ampliers (six outputs on the PS 6648, four outputs on the PS
4248).
Each single output is protected by a fuse (max. current: 15 A) and shall be connected to an
amplier only.
When a yellow LED is lit, its respective fuse is blown (and the output is not powered).
6AUX 1 - 6 (PS 6648) / AUX 1 - 2 (PS 4248)
48 V auxiliary outputs to connect other devices, such as routers, paging microphones,
controllers, etc. (six aux outputs on the PS 6648, two aux outputs on the PS 4248).
On PS 6648, aux output pair 1/2 shares a single fuse, the same for the aux output pair 3/4,
while both aux outputs 5 and 6 have a separate fuse.
On PS 4248, both aux outputs are protected by a separate fuse.
Max. current per each fuse: 2 A.
When a yellow LED is lit, its respective fuse is blown (and outputs are not powered).
7TEMP SENSOR input
Input for the temperature sensor.
8BATT FAULT logic output with internal relay
Pins (from left to right): normally open, common, normally closed.
RELAY STATE DESCRIPTION
ON Normal battery condition.
OFF
Disconnected batteries, too high resistance of the
battery circuit or battery voltage below the preset level
(discharged batteries).
PS 6648
PS 4248
4 7 8 9
10
11 12 1365
4 7 8 9
10
11 12 1365

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9GEN. FAULT logic output with internal relay
Pins (from left to right): normally open, common, normally closed.
10 MAINS FAULT logic output with internal relay
Pins (from left to right): normally open, common, normally closed.
11 EXT. FAULT logic input with LED
External fault signal logic input for a dry contact.
This logic input is activated by an open circuit between its contacts (the FAULT LED is
blinking).
When this logic input is not used, it is necessary to leave the jumper to short its two pins.
12 BATTERY dip-switches
Dip-switches to set the battery capacity (charging current limit is calculated as a function
of the battery capacity) and the maximum battery circuit resistance.
See the INSTALLATION AND DIP-SWITCH SETTINGS manual section for details about all
dip-switch settings.
13 Input (IEC type C13, male) for the power cord connected to mains (230 V ac, 50 / 60 Hz).
RELAY STATE DESCRIPTION
ON No fault.
OFF
Either power supply internal fault or an external fault
(EXT FAULT command activation).
It can also indicate blown fuses on OUT and AUX
outputs.
RELAY STATE DESCRIPTION
ON Normal operation (mains present)
OFF No mains power or rectier fault.

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When the mains power supply is present, PS 6648 / PS 4248 delivers power to AUX outputs
(only) and simultaneously charges batteries.
After a mains power failure, all the load is automatically transferred to batteries (battery
operation mode).
BLOCK DIAGRAM
PS 6648 / PS 4248 backup power supply units are designed for voice alarm systems, in
which ampliers are normally directly powered by mains, therefore there are two separate
output circuits:
1. Ampliers powered by the main outputs
-Ampliers are not powered by PS 6648 / PS 4248 when the mains power is present.
-After a mains power failure, when there is no alarm / evacuation in progress, ampliers
only need a very low power from batteries.
-If an alarm / evacuation occurs during a mains power failure, ampliers could need high
power from batteries.
2. Other devices (of the voice alarm system) that need to continuously operate (routers,
paging microphones, other controllers, etc.) are powered by the aux outputs.
OPERATION
MICROPROCESSOR CONTROLLER
RECTIFIER 400W
LED PANEL
1234 5 6
POWER SUPPLY OUTPUTS FOR AMPLIFIERS
12V BATTERY 12V BATTERY
230V 50-60Hz
Mains
Battery
Charging
FAN
LVDD
Fault
BAT 48V
EXTERNAL
SIGNALLING INPUT
AUX POWER SUPPLY OUTPUTS
BATTERY CONNECTORS
USB SOCKET
CURRENT
MEASUREMENT SYSTEM
FAN
REMOTE SIGNALLING OUTPUTS
Mains faultBat fault Gen fault
Temp
sensor
RESISTANCE
MEASUREMENT SYSTEM
Out
Aux
1
2
3
4
5
6
BD
Ext
fault
ST
12V BATTERY 12V BATTERY

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PS 6648 / PS 4248 power supply units also provide these following features (besides the
functions already described of both main and auxiliary outputs):
-Charging and monitoring external batteries.
-Testing the resistance of the battery circuit (and reading its value with the PC application via USB).
-Protection of batteries against deep discharge by LVDD (Low Voltage Disconnecting Device).
-Monitoring of the battery charging current, the AUX output current and occurrence of load
on the main outputs (OUT) when mains power is present (by reading their values with the
PC application via USB).
-Disconnecting all the AUX outputs by the BD (Battery Disconnection) protection when the
battery terminals or the main outputs (OUT) are shorted (or batteries are not connected).
-This protection secures that voltage on AUX outputs is still present despite a battery failure.
All functions are managed by the internal microcontroller, which receives all signals
(voltage, current, temperature, faulty states, etc.) from the key points of the power supply
unit, controls all logic output relays, LED indicators and communicates with an external
computer (PC) via USB.
‘COLD START’ WITH BATTERIES ONLY
If mains power is missing, it is still possible to start the power supply unit operation from
batteries by using the ST push-button on the front panel. Press and hold the push-button
until the front panel LEDs are lit (it takes about 5 s). Battery voltage needs to be over the
minimum level (about 44 V).
Note:if the power supply unit has been started thanks to the mains power and the connected batteries
have avoltage below the required level, pressing the st push-button will give no effect.
BATTERY OPERATION MODE SELECTION
The power supply unit can operate in two different battery operation modes:
-a) BATTERY FLOAT CHARGING
-b) NON-CONTINUOUS BATTERY CHARGING
The selection of one of these two modes can be done only by the application for (PC) via USB.
Default factory setting is BATTERY FLOAT CHARGING.
a) BATTERY FLOAT CHARGING
When the mains power is present, the power supply unit maintains batteries fully charged.
Its microcontroller supervises the batteries, maintaining them at their oat voltage (which
depends on the ambient temperature, so the external temperature sensor should be
connected).
If the external sensor is absent (or not connected), the microcontroller will maintain a
voltage corresponding to the ambient temperature of 25°C (77°F).
b) NON-CONTINUOUS BATTERY CHARGING
If this mode is selected (when the mains power is present), it will be applied after a full
battery recharge and a oat charge for 48 hours (default factory setting).
Subsequently, batteries will be automatically disconnected from the internal charger, which
will maintain on its outputs a voltage 0.2 V higher than the current battery voltage.
Such a state lasts for either 18 days (default factory setting) or until the self-discharging of
batteries reaches the preset voltage level. In both cases the rell starts.
After recharging batteries and operating in oat charge for 48 hours, batteries will be
disconnected from the internal charger for 18 days again. If the mains power supply
fails (or if during its presence, high peaks of current appear on outputs), batteries will be
immediately reconnected.
The non-continuous battery charging mode increases the life-cycle of batteries (by limiting
the time of current ow through batteries, in order to reduce the positive electrode
corrosion of the cells and loss of water contained in electrolyte).

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DEVICE STATE
The power supply unit is equipped with front panel LEDs and remote signalling.
A fault indication is kept until the problem is solved.
The remote signalling is made by three logic outputs: MAINS FAULT, BATT FAULT and GEN.
FAULT. Each logic output has an internal relay, its socket has three pins and is electrically
separated from all other circuits.
During normal operation, all internal relays are turned on (therefore, a fault indication is
executed by switching off its respective relay).
Logic output pins (from left to right): normally open, common, normally closed (as shown
in the silkscreen close to the MAINS FAULT output).
DEVICE RESET
The ST push-button can be used (by a short press) to cancel two possible internal errors:
-Failure of voltage regulation circuit in the internal charger.
-Checksum error in EPROM memory.
DIGITAL INTERFACE
The power supply unit is equipped with a USB port (on its front panel) usable for servicing.
The PC software allows to perform diagnosis, making possible to check numerous
parameters and modify its default settings.
The USB port is galvanically insulated from all the other circuits.
SAFETY
The power supply unit is a CLASS I device according to the standard EN 60950-
1:2006+A1:2009 (IEC950), designed for connecting to a permanent one-phase installation
with an earthing wire.
The metal case of the power supply unit is connected to a PE terminal.
The circuits used for connecting batteries, remote signalling and 48V outputs are separated
from the internal power supply section and from the case.
Relay contacts for remote signalling (logic outputs) are fully separated (galvanic insulation)
from all other circuits (including the outputs).
The external fault command input is referred to the potential of the negative pole of
batteries.
MAINTENANCE
Output voltages and signalling thresholds are preset to factory default values.
After installing, the power supply unit needs supervision by the service team (due to its
emergency purpose) and should be subjected to periodic checks and tests. Anyway, this
device does not require any particular maintenance operation to be performed, just keep
it clean.
See also the MAINTENANCE manual section, about the output fuses, fault diagnosis and
troubleshooting.

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The power supply unit is designed for installation in a standard 19” rack cabinet (one unit).
Fix it to into the rack cabinet with four screws (through holes located on the front panel
corners).
Its net weight is 4.9 kg, so guide rails should be used and installed in such a way not to
cover the ventilation holes on both sides of its case (leave at least 8 cm free per side).
DIP-SWITCH SETTINGS
The rear panel dip-switches 1, 2 and 3 (CAP) allow to set the battery capacity.
The power supply unit is designed to operate with VRLA-AGM batteries.
The adequate battery capacity shall be chosen taking into account the operation time and
the total power of all foreseen speakers.
The minimal value of the battery capacity is 25 Ah, value that can be increased by using
the three dip-switches 1-2-3. The resulting capacity is a sum of 25 Ah and all values
corresponding to each dip-switch set to ON (dip 1: +25 Ah, dip 2: +50 Ah, dip 3: +100
Ah), thus the maximum possible capacity value is 200 Ah.
The rear panel dip-switches 4, 5 and 6 (Ri) allow to set the maximum resistance of the
battery circuit.
This setting depends on the speaker total power.
See also BATTERY CIRCUIT RESISTANCE (in the STARTUP manual section) for the proper
dip-switch settings.
The minimal value of the resistance is 30 mΩ, value that can be increased by using the three
dip-switches 4-5-6.The resulting resistance is a sum of 30 mΩ and all values corresponding
to each dip-switch set to ON (dip 4: +10 mΩ, dip 5: +20 mΩ, dip 6: +40 mΩ), thus the
maximum possible resistance value is 100 mΩ.
INSTALLATION AND DIP-SWITCH SETTINGS
BATTERY CAPACITY DIP- SW. 1 DIP- SW. 2 DIP- SW. 3
25 Ah
50 Ah ON
75 Ah ON
100 Ah ON ON
125 Ah ON
150 Ah ON ON
175 Ah ON ON
200 Ah ON ON ON
RESISTANCE DIP- SW. 4 DIP- SW. 5 DIP- SW. 6
30 mΩ
40 mΩ ON
50 mΩ ON
60 mΩ ON ON
70 mΩ ON
80 mΩ ON ON
90 mΩ ON ON
100 mΩ ON ON ON
1
ON
Cap
Battery
Ri
42 53 6
1
ON
Cap
Battery
Ri
42 53 6

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CONNECTIONS
The table below shows the type and number of connectors used, their maximum ratings
and wire sections.
CONNECTION OF THE POWER SUPPLY UNIT TO THE MAINS POWER SUPPLY
Connect the power supply unit to the mains by using a 3-wire cable (1.5 mm² cross-section)
equipped with the IEC plug C13 type.
The power supply is not equipped with its own main switch, therefore the mains plug is used as
the disconnect device and it shall remain readily operable.
The electric system should be a permanent type and equipped with a surge protection system.
CONNECTION AND PROTECTION OF THE BATTERY CIRCUIT
WARNING:
1. Since the power supply unit is not equipped with a fuse for the battery
circuit, it is necessary to insert one after the battery positive pole. It is also
allowed to put the fuse in a link between two batteries.
2. Reverse connection of battery terminals (wrong polarity) may cause serious
damages to both the power supply unit and connected devices.
3. Batteries should be precharged before installation.
Batteries shall be linked to the rear panel BATT. 48V terminals (with a suitable cable,
max. 2 m long), paying attention to their polarity.
To have the minimum resistance of the leads, care should be taken when tightening the
screws.
The maximum voltage drop should not exceed 0.6 V.
The wire cross section of battery cables should be chosen according the total speaker
power.
See the next table:
INPUT / OUTPUT TYPE OF PLUG AND WIRE SECTIONS PS 6648 PS 4248
Mains power
230V ac 50 Hz / 60 Hz IEC C13 1 pc. 1 pc.
Main outputs (OUT) to ampliers PC 5/2-STLC-7.62
6 mm² 41 A with lock 6 pcs. 4 pcs.
AUX outputs MC 1.5/2-ST-3.81
1.5 mm² 8 A 6 pcs. 2 pcs.
Temperature sensor input
Temp sensor
MC 1.5/2-ST-3.81
1.5 mm² 8 A 1 pc. 1 pc.
Logic outputs
Batt fault, Gen. Fault, Mains fault
FMC 1.5/3-ST-3.81
1.5 mm² 3 pcs. 3 pcs.
Input for external fault command
Ext fault
MC 1.5/2-ST-3.81
1.5 mm² 1 pc. 1 pc.
Batteries (48 V) Two-pole M8 bolt / nut terminal
50 mm² 100 A
TOTAL SPEAKER POWER SUGGESTED WIRED CROSS-SECTION TOTAL RESISTANCE OF CABLES AND
BATTERY FUSE
≤ 1500 W 10 mm² [1.8 mΩ / 1 m] ≤ 12 mΩ
1500 ÷ 3000 W 16 mm² [1.1 mΩ / 1 m] ≤ 8 mΩ

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AMPLIFIER CONNECTION
PS 6648 has 6 main outputs, PS 4248 has 4 main outputs.
Each main output allows the connection of a single amplier (max. 500 W).
Amplier connection should be made with cables having a 4 mm² wire cross-section, as the
voltage drop should not exceed 0.2 V.
If an amplier is matched to a backup / spare unit, it will be possible to connect both
ampliers to the same power supply unit output (if there are no free outputs left).
This parallel link shall not be directly made on the power supply unit.
CONNECTION OF OTHER DEVICES TO THE AUX OUTPUTS
All devices (of the voice alarm system) that need to be continuously powered have to be
connected to AUX outputs.
In the PS 6648 model, the rst four AUX outputs are organized in pairs (1 with 2, 3 with 4)
that share the same fuse.AUX 5 and 6 have their own separate fuses.
PS 4248 has two AUX outputs, both with separate fuses.
EXTERNAL FAULT INPUT CONNECTION
The power supply unit has an input (on its rear panel) for an external fault command.
This input is activated by an open circuit between its contacts (the FAULT LED is blinking).
When this input is not used, it needs a jumper (supplied) to short its two pins.
CONNECTION OF LOGIC OUTPUTS
The three logic outputs (MAINS FAULT,BATT FAULT and GEN.FAULT) have 3-pin independent
sockets.
Socket pins (from left to right): normally open, common, normally closed (as shown in the
silkscreen close to the MAINS FAULT output).
All internal relays are normally turned on, so a fault indication is executed by switching off
its respective relay.
TEMPERATURE SENSOR CONNECTION
Connect the thermometer to the TEMP SENSOR input.
It should be placed between two adjacent batteries, in contact with their sides.

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STARTUP
The rst startup of the voice alarm system (including PS 6648 / PS 4248 and connected
batteries) should be made by qualied service personnel (or properly trained and
authorized).
The tests during the rst system startup are necessary to ensure safe and reliable operation.
First, check the system completeness and all other devices about their compliance with the
electrical specications of the power supply unit.
Also check all connections as well as the used battery type.
note: if (as result of acharger fault or its disconnection from the mains power) an amplifier is
powered from a48 v main output (when all equipment has already been powered by batteries), such
astate will lead to uncontrolled discharging of batteries.
STARTUP SEQUENCE
Correct sequence to turn devices on:
1. All ampliers and PS 6648 / PS 4248 are initially switched off.
2. Set the battery capacity dip-switches on the rear panel (see the INSTALLATION AND
DIP-SWITCH SETTINGS manual section).
3. Set the battery circuit resistance dip-switches on the rear panel (see the INSTALLATION
AND DIP-SWITCH SETTINGS manual section and the table in the next paragraph
BATTERY CIRCUIT RESISTANCE).
4. Connect batteries (by inserting a fuse) to the power supply unit properly (make sure the
polarity is correct).
5. Switch on all ampliers (from mains) and then PS 6648 / PS 4248.
6. Test the battery circuit resistance by pressing and holding the ST push-button (on
the front panel) for about 10 seconds (see the next paragraph BATTERY CIRCUIT
RESISTANCE). The battery circuit resistance value can be read by using the dedicated
PC software.
7. Check the operation after disconnecting the mains power (see the paragraph CHECK
THE OUTPUT VOLTAGE AFTER DISCONNECTING THE MAINS POWER).
8. Check the operation after disconnecting batteries (see the paragraph CHECK THE
OPERATION WITHOUT BATTERIES).
BATTERY CIRCUIT RESISTANCE
The limitation of the maximum battery circuit resistance is necessary to secure enough
delivered power (from the main outputs of PS 6648 / PS 4248) for the proper operation of
the voice alarm system, during (for instance) a re alarm when in battery operation mode.
See the next table: although the maximum possible value is 100 mΩ, however the setting
of the limit for the battery circuit resistance should be lower.
In practice, the battery circuit should have lower resistance than the maximum value set
and the margin to the limit has to take into account an increase of the resistance due to
battery ageing.
Resistance value settings (column no.3) are indicated as function of the system total
speaker power (column no.1).

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1 2 3 4
TOTAL SPEAKER
POWER
EXPECTED
BATTERY CIRCUIT RESISTANCE
VALUE (¹)
SETTING OF MAXIMUM
BATTERY CIRCUIT RESISTANCE Ri MARGIN (²)
VALUE DIP-SW. 4 DIP-SW. 5 DIP-SW. 6
500 W ≤ 40 mΩ 80 mΩ ON off ON 40 mΩ
1000 W ≤ 36 mΩ 70 mΩ off off ON 34 mΩ
1500 W ≤ 28 mΩ 60 mΩ ON ON off 32 mΩ
2000 W ≤ 22 mΩ 50 mΩ off ON off 28 mΩ
2500 W ≤ 18 mΩ 40 mΩ ON off off 22 mΩ
3000 W ≤ 18 mΩ 40 mΩ ON off off 22 mΩ
(¹) Battery circuit resistance value periodically measured by PS 6648 / PS 4248.
It is possible to initiate the battery circuit resistance test by pressing and holding the
ST push-button (on the front panel) for about 10 seconds. This test is only possible for
precharged batteries.
The battery circuit resistance value can be read by using the dedicated PC software.
(²) The margin is the difference between the setting of the maximum battery circuit
resistance (column no.3, a higher level returns a fault) and the expected value (column
no.2).
It approximately corresponds to the nominal resistance of batteries, having sufcient
capacity for the system total speaker power (column no.1).
CHECK THE OUTPUT VOLTAGE AFTER DISCONNECTING THE MAINS POWER
Disconnect the power supply unit from the mains: PS 6648 / PS 4248 should operate with
only batteries, powering all its outputs.
Check the output voltage by using a voltmeter.
In this state, the front panel MAINS LED is off and both FAULT and BATTERY LEDs are lit.
Both internal relays of logic outputs MAINS FAULT and GEN. FAULT are now de-energized
(the current state of their contacts is like the one indicated on the rear panel silkscreen).
The logic output state can be simply tested by an ohmmeter.
All connected devices should operate normally during this check.
CHECK THE OPERATION WITHOUT BATTERIES
When the PS 6648 / PS 4248 is powered from the mains, break the battery circuit.
This event should be detected by PS 6648 / PS 4248 within about 100 seconds.
The FAULT LED lights up.
Both internal relays of logic outputs BATT FAULT and GEN. FAULT are now de-energized
(the current state of their contacts is like the one indicated on the rear panel silkscreen).
All connected devices should operate normally during this check.

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SPECIFICATIONS
(1) Value of maximum charge current depends on battery capacity (see the next paragraph
RELATION BETWEEN THE MAXIMUM BATTERY CAPACITY AND THE AUX
OUTPUT CURRENT).
(2) Required value within given range may be set with 10 mΩ accuracy by the dip-switches
for the selection of the battery circuit maximum resistance.
(3) Given range includes values between the voltage on discharged batteries (at the end
of the battery operation mode) and the boost charge voltage, taking into account
temperature compensation.
(4) It depends on the battery capacity (see the next paragraph RELATION BETWEEN THE
MAXIMUM BATTERY CAPACITY AND THE AUX OUTPUT CURRENT).
(5) At current 100 A, the internal voltage drop between the connectors for batteries and
main outputs is 0.4 V.
ELECTRIC TECHNICAL DATA
Mains power voltage 230 V +10% –15% 50/60 Hz
Power factor 0.94
Efciency (during battery charging) 84%
Earth leakage current ≤ 1.5 mA
Max. current draw from mains 2.7 A
Battery nominal voltage 48 V
Float charge voltage (at temp. 25°C) 54.2 V
Boost charge voltage (at temp. 25°C) 55.7 V
Temperature compensation index
for both oat and boost charge –80 mV / ºC
Maximum capacity of connected batteries 200 Ah
Max. charging current 2 ÷ 8 A (1)
Max. resistance of battery circuit 30 ÷ 100 mΩ (2)
Battery current consumption (for own needs) < 55 mA
Current consumption from batteries when disconnected by LVDD (Low Voltage
Disconnecting Device) < 1 mA
LVDD battery disconnection threshold 40.8 V
Range of output voltage changes 40.0 ÷ 57.6 V (3)
Max. current (for ampliers) from main outputs:
- PS 6648
- PS 4248
6 x 15 A
4 x 15 A
Max. current from auxiliary outputs:
- PS 6648 (AUX 1/2,AUX 3/4, AUX 5, AUX 6)
- PS 4248 (AUX 1,AUX 2)
4 x 2 A
2 x 2 A
Maximum continuous total current
on all 48 V Aux outputs (I max. a)0 ÷ 7 A (4)
Max. allowed total current sourced from battery when the mains power is not
available 100 A (5)

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RELATION BETWEEN THE MAXIMUM BATTERY CAPACITY
AND THE AUX OUTPUT CURRENT
The internal rectier is used to charge batteries and power all AUX outputs.
The maximum capacity of used batteries is limited by the total AUX output current, as
shown in the table below:
Max. total continuous
current of all
AUX outputs *
01 A 2 A 3 A 4 A 5 A 6 A 7 A
Max. capacity of
batteries 200 Ah 180 Ah 160 Ah 130 Ah 100 Ah 80 Ah 50 Ah 25 Ah
* This current is marked in the specications as I max. a .
CHOICE OF BATTERY CAPACITY
The choice of the battery capacity must take into account the max. current draw and local
regulations (to ensure a minimum operating time of the system, either for a normal use or
during an emergency).
Ampliers require power supply without a signicant voltage drop.
Therefore, batteries must full requirements for voltage and resistance in order to assure
the proper operation of ampliers during alarms / evacuations.
Parameters to be considered when an alarm is in progress (during battery operation):
-Speaker total power (see BATTERY CIRCUIT RESISTANCE in the STARTUP manual
section).
-The total resistance from batteries to the amplier connectors (see CONNECTION AND
PROTECTION OF THE BATTERY CIRCUIT in the CONNECTIONS manual section).
The resistance should not cause a voltage drop higher than 1.2 V.
Batteries should not have a too high voltage drop entailing switching off of ampliers or
the LVDD protection automatic insertion.
RECOMMENDED OPERATION CONDITIONS
Relative humidity max 80%
Direct sun exposure not permissible
Impacts during operation not permissible
Ambient temperature:
-Allowed storage temperature
-Operating temperature
–40 ÷ +85°C / –40 ÷ +185°F
–5 ÷ +45°C / +23 ÷ +113°F

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DIMENSIONS mm
MAINTENANCE
OUTPUT FUSES
Output fuse holders are located on the rear panel.
Main output fuses: 15 A (blade type).
Auxiliary output fuses: 2 A (blade type).
Output fuses blow due to short circuits or overloads.
The voice alarm system personnel can only replace the output fuses. Other fuses inside
the power supply unit (when blown) need to be replaced by an authorized service centre.
445
290 31
483
43
465
31.8
mm