Lab.gruppen PLM Series User manual
Rev. 1.0.2
Item no. OM-PLM
Operation Manual
PLM™Series
Powered Loudspeaker Management™systems
2 PLM Series Operation Manual
1 CONTENTS
1 CONTENTS...................................................................................................................................................2
2 APPROVALS ................................................................................................................................................6
3 WARNINGS .................................................................................................................................................6
3.1 Explanation of graphical symbols ........................................................................................................6
3.1.1 WARNING ................................................................................................................................6
3.1.2 CAUTION..................................................................................................................................6
3.2 Important Safety Instructions ..............................................................................................................6
3.3 User responsibility ...............................................................................................................................7
3.3.1 Mains connection grounding ....................................................................................................7
3.3.2 Speaker output hazard..............................................................................................................7
3.3.3 Radio interference ....................................................................................................................7
3.3.4 Speaker damage.......................................................................................................................7
3.3.5 Maintenance.............................................................................................................................7
4 WELCOME...................................................................................................................................................8
4.1 Introduction .........................................................................................................................................8
4.2 Main Features......................................................................................................................................8
4.2.1 Amplier platform.....................................................................................................................8
4.2.2 Amplier DSP: Gain, ISVPL™, load verication and performance monitoring..........................8
4.2.3 Dolby®Lake®Processing and Controller ..................................................................................9
4.2.4 SmaartLive®integration............................................................................................................9
4.2.5 Dante™audio network ..............................................................................................................9
5 INSTALLATION .........................................................................................................................................10
5.1 Unpacking..........................................................................................................................................10
5.2 Mounting ...........................................................................................................................................10
5.3 Rear Mounting ...................................................................................................................................10
5.4 Cooling...............................................................................................................................................11
5.5 Operating voltage ..............................................................................................................................12
5.6 Grounding ..........................................................................................................................................12
6 PLM SERIES FEATURES ..........................................................................................................................13
6.1 Front Panel overview .........................................................................................................................13
6.2 Rear Panel overview ..........................................................................................................................15
6.2.1 Input connectors and Links ....................................................................................................15
6.2.2 Output connectors..................................................................................................................15
6.2.3 Network connectors...............................................................................................................16
6.2.3.110/100Base-T network ...........................................................................................................16
6.3 Integrated Dolby Lake Processing .....................................................................................................17
6.3.1 Dolby Lake Controller (DLC) PLM Edition software ..............................................................17
7 OPERATION AND PERFORMANCE ........................................................................................................18
7.1 Introduction to Operation...................................................................................................................18
7.1.1 Operation precautions ............................................................................................................18
7.2 Power Output Performance...............................................................................................................18
7.2.1 Symmetrical power ................................................................................................................18
7.2.2 Asymmetrical power ..............................................................................................................18
7.2.3 Power over time .....................................................................................................................18
7.3 Amplier and Load Protection Systems ............................................................................................19
7.3.1 Inter-Sample Voltage Peak Limiter (ISVPL) ............................................................................19
7.3.2 Current Peak Limiter (CPL) .....................................................................................................20
7.3.3 Power Average Limiter (PAL) .................................................................................................20
7.3.4 Current Average Limiter (CAL) ...............................................................................................20
PLM Series Operation Manual 3
CONTENTS 1
7.3.5 Voltage Clip Limiter...................................................................................................................20
7.3.6 Temperature Protection ............................................................................................................20
7.3.7 DC Protection............................................................................................................................21
7.3.8 VHF Protection..........................................................................................................................21
7.3.9 Short circuit protection..............................................................................................................22
7.4 Power Supply.....................................................................................................................................22
8 SIGNAL FLOW AND PROCESSING.........................................................................................................23
8.1 Signal Flow .......................................................................................................................................23
8.2 Loudspeaker processor conguration................................................................................................24
8.3 Modules and Frames .........................................................................................................................25
8.3.1 LoadLibrary™ and Fingerprints.................................................................................................25
8.3.2 Super Modules .........................................................................................................................26
8.4 Presets...............................................................................................................................................26
8.4.1 Module Presets.........................................................................................................................26
8.4.2 Frame Presets ..........................................................................................................................26
8.4.3 Subsystem Presets ..................................................................................................................26
8.4.4 System Presets ........................................................................................................................26
9 FRONT PANEL INTERFACE .....................................................................................................................27
9.1 Front Panel Navigation.......................................................................................................................27
9.1.1 General description of navigation in the PLM.........................................................................27
9.1.2 Pinging Modules in the DLC PLM Edition software from the PLM .......................................27
9.2 Key Lock Front Panel .........................................................................................................................28
9.3 Power button ....................................................................................................................................28
9.4 Mute Enable button ..........................................................................................................................28
9.5 Meter button .....................................................................................................................................28
9.6 Menu button .....................................................................................................................................28
9.7 Network activity LED ........................................................................................................................29
9.8 Rotary encoder .................................................................................................................................29
9.9 Exit button ........................................................................................................................................29
9.10 Soft-function buttons ....................................................................................................................... 30
9.10.1 Mute Functions ...................................................................................................................... 30
9.10.1.1 PLM Input Mute............................................................................................................ 30
9.10.1.2 Module Input Mute....................................................................................................... 30
9.10.1.3 Module Output Mute.....................................................................................................31
9.10.1.4 Power Output Mute.......................................................................................................31
9.10.2 LED Faults, Warnings and Clip indications..............................................................................31
9.10.2.1 Green indications.......................................................................................................... 33
9.10.2.2 Yellow indications......................................................................................................... 33
9.10.2.3 Red indications............................................................................................................. 33
9.11 Meter Mode...................................................................................................................................... 35
9.11.1 Meter view 1 – Home View................................................................................................... 36
9.11.2 Meter View 2 – Module View................................................................................................ 36
9.11.3 Meter View 3 – Temperature View.........................................................................................37
9.12 Menu Mode...................................................................................................................................... 38
9.12.1 Menu View ............................................................................................................................ 38
9.12.2 Module submenu .................................................................................................................. 39
9.12.2.1 User Gain...................................................................................................................... 39
9.12.2.2 Delay ............................................................................................................................ 39
9.12.2.3 Phase Reverse.............................................................................................................. 39
9.12.2.4 Amp Gain...................................................................................................................... 39
9.12.2.5 Limiters......................................................................................................................... 39
4 PLM Series Operation Manual
9.12.2.5.1 Inter-Sample Voltage Peak Limiter (ISVPL)........................................................... 40
9.12.2.5.2 MaxPeak Level (MaxPeakLvl)............................................................................... 40
9.12.2.5.3 MaxRMS Level (MaxRMSLvl) .............................................................................. 40
9.12.2.5.4 MaxRMS Corner (MaxRMSCor) .......................................................................... 40
9.12.5.5.5 MaxRMS Attack (MaxRMSAtk) ........................................................................... 40
9.12.2.5.6 MaxRMS Release (MaxRMSRel) ......................................................................... 40
9.12.2.6 Mutes ........................................................................................................................... 40
9.12.3 Input Routing and Settings submenu......................................................................................41
9.12.3.1 Input selection and sensitivity settings..........................................................................41
9.12.3.2 IsoFloat™.......................................................................................................................42
9.12.3.3 AES/EBU input termination ...........................................................................................42
9.12.4 Attenuation submenu............................................................................................................. 43
9.12.5 Frame submenu ..................................................................................................................... 43
9.12.5.1 Frame Name ................................................................................................................. 43
9.12.5.2 Frame Info .................................................................................................................... 43
9.12.5.2.1 Firmware version (‘FW version’)........................................................................... 44
9.12.5.2.2 Latency (‘Inh. Latency’) ........................................................................................ 44
9.12.5.2.3 Max Output Voltage (‘MaxOutVolt’)..................................................................... 44
9.12.5.2.4 Max Output Current (‘MaxOutCurr’) .................................................................... 44
9.12.5.2.5 Serial Number (‘Serial no.’)................................................................................... 44
9.12.5.3 Frame Reset ................................................................................................................ 44
9.12.5.3.1 Factory Reset ....................................................................................................... 44
9.12.5.3.2 Soft Reset ............................................................................................................ 44
9.12.5.4 Network........................................................................................................................ 44
9.12.5.4.1 IP Address ............................................................................................................ 45
9.12.5.4.2 MAC Address....................................................................................................... 45
9.12.5.4.3 Frame ID............................................................................................................... 45
9.12.5.4.4 Network statuses (‘Online’).................................................................................. 45
9.12.5.4.5 IP Mask ................................................................................................................ 45
9.12.5.5 Latency match.............................................................................................................. 45
9.12.5.6 Display adjustments ..................................................................................................... 45
9.12.5.6.1 Display Contrast ................................................................................................... 45
9.12.5.6.2 Dimming............................................................................................................... 45
9.12.6 Frame Preset submenu.......................................................................................................... 45
9.12.7 LoadSmart™........................................................................................................................... 46
9.12.7.1 Congure # of cabinets in parallel ................................................................................. 46
9.12.7.2 LoadSmart verication.................................................................................................. 46
9.12.8 Dante.......................................................................................................................................47
9.12.8.1 Break In Physical Line....................................................................................................47
9.12.8.2 Probe Routing................................................................................................................47
10 BACK PANEL INTERFACE ....................................................................................................................... 48
10.1 Power inlet........................................................................................................................................ 48
10.1.1 PowerCon® wiring details...................................................................................................... 48
10.2 Audio Input and Links ....................................................................................................................... 48
10.2.1 Analog inputs and Links ......................................................................................................... 48
10.2.1.1 Unbalanced operation ................................................................................................... 48
10.2.1.2 Iso-Float electronic balancing ....................................................................................... 49
10.2.2 Digital inputs and Links.......................................................................................................... 49
10.3 Speaker Output Connections............................................................................................................ 50
10.3.1 Speakon Output Connectors.................................................................................................. 50
10.3.2 Binding Post Output Connectors............................................................................................51
1 CONTENTS
PLM Series Operation Manual 5
10.4 RJ45 connectors................................................................................................................................51
11 APPENDIX .................................................................................................................................................52
11.1 Faults and warnings overview ...........................................................................................................52
11.2 Maintenance ..................................................................................................................................... 55
11.3 Additional Documentation ................................................................................................................ 55
11.4 Current draw and thermal dissipation specications........................................................................ 55
11.5 Factory Default Settings ................................................................................................................... 55
11.6 Glossary of terms, acronyms, abbreviations, etc. used in this manual............................................. 55
12 APPLICATION GUIDE .............................................................................................................................. 62
12.1 I/O Panels ......................................................................................................................................... 62
12.2 Power Distribution ............................................................................................................................ 62
12.3 Gain Structure................................................................................................................................... 63
12.3.1 Gain / Level Optimization ...................................................................................................... 63
12.4 Speaker congurations ......................................................................................................................67
12.5 Connecting Digital Audio Devices .....................................................................................................67
12.5.1 AES/EBU digital audio .............................................................................................................67
12.5.2 Sampling rates and latency.....................................................................................................67
12.5.3 Interconnecting digital audio .................................................................................................. 68
12.5.4 Cable...................................................................................................................................... 68
12.5.5 Accessories ........................................................................................................................... 69
12.5.5.1 Passive splitters............................................................................................................ 69
12.5.5.2 Distribution ampliers .................................................................................................. 69
12.5.6 Application hints .................................................................................................................... 69
12.6 Firmware Upgrades ...........................................................................................................................70
12.6.1 Firmware Upgrades Using the Update Utility .........................................................................70
12.6.2 Firmware Upgrades Using the Dolby Lake Controller PLM Edition........................................71
12.7 Hot swapping PLM devices...............................................................................................................72
13 TECHNICAL SPECIFICATIONS ................................................................................................................73
14 WARRANTY ..............................................................................................................................................74
CONTENTS 1
6 PLM Series Operation Manual
This equipment conforms to the requirements of the EMC Directive 2004/108/EC and the requirements of the Low Voltage Directive
2006/95/EC.
Standards applied: EMC Emission EN55103-1, E3
EMC Immunity EN55103-2, E3, with S/N below 1% at normal operation level.
Electrical Safety EN60065, Class I
This equipment is tested and approved according to the U.S. safety standard ANSI/ UL 60065 and Canadian safety standard CSA
C22.2 NO. 60065. ETL made the tests and they are a Nationally Recognized Testing Laboratory (NRTL).
3.1 Explanation of graphical symbols
The lightning symbol within a triangle is intended to alert the user to the presence of un-insulated “dangerous voltage” within the amplier’s
enclosure that may be of sufcient magnitude to constitute a risk of electric shock to humans.
The exclamation point within a triangle is intended to alert the user to presence of important operating and service instructions in the literature
accompanying the product.
3.1.1 WARNING 3.1.2 CAUTION
3.2 Important Safety Instructions
Before using your PLM, be sure to carefully read the applicable items of this Quick Start and Field Reference Guide and the Safety Instructions.
Keep this manual for future reference.1.
Heed all warnings.2.
Follow all instructions.3.
Do not use this unit near water.4.
Do not spill water or other liquids into or on the unit. Do not operate the unit while wet or standing in liquid.5.
Clean only with dry cloth.6.
Do not block the air intake or exhaust ports. Install the unit in accordance with the instructions.7.
Do not operate the unit near heat producing devices such as radiators, heat registers, stoves or other apparatus that produce heat. Always operate8.
the unit with the chassis ground wire connected to the electrical safety earth. Do not defeat the safety purpose of a grounding-type plug. A
grounding-type plug has two pins and a third grounding prong. The third prong is provided for your safety. If the provided plug does not t into your
outlet, consult an electrician for replacement of the obsolete outlet.
Connect only to AC power outlets rated 100-120 V or 200-240 V, 50-60 Hz as dictated by the unit’s voltage conguration.9.
Do not use this unit if the power cord is broken or frayed. Protect the power cord from being walked upon or pinched, particularly at the plug and10.
the point where it exits from the apparatus.
Only use accessories specied by the manufacturer.11.
The unit is intended to use in a 19” rack. Follow the mounting instructions. When a rack on wheels is used, use caution when moving the loaded12.
rack to avoid injury from tipping over.
Unplug this apparatus during lightning storms or when unused for long periods of time.13.
Do not connect the unit’s outputs in parallel or series with any other unit’s output. Do not connect the unit’s output to any other voltage source, such14.
as battery, mains source, or power supply, regardless of whether the unit is turned on or off.
Do not run any of the unit’s outputs back into another channel’s input.15.
Refer all servicing to qualied service personnel. Servicing is required when the apparatus has been damaged in any way such as:16.
Power-supply cord or plug is damaged.▸
Liquid has been spilled into the unit▸
An object has fallen into the unit▸
The unit has been exposed to rain or moisture▸
The unit does not operate normally▸
The unit was dropped or the chassis is damaged▸
17. Do not remove top or bottom covers. Removal of the covers will expose hazardous voltages. There are no user serviceable parts inside and
removal may void the warranty.
18. An experienced user shall always supervise this professional audio equipment, especially if inexperienced adults or minors are using the
equipment.
19. The mains plug is used as the disconnect device and shall remain readily accessible. If the mains plug is not readily accessible
due to mounting in a 19” rack, then the mains plug for the entire rack must be readily accessible.
20. The US National Differencescl.16.3 requires that network cables must be ame rated VW-1.
2 APPROVALS
To reduce risk of re or electric shock, do not expose this
apparatus to rain or moisture.
To reduce the risk of re or electric shock, do not remove
screws. No user-serviceable parts inside. Refer servicing to
qualied service personnel
3 WARNINGS
PLM Series Operation Manual 7
WARNINGS 3
3.3 User responsibility
3.3.1 Mains connection grounding
Your PLM must be connected to a grounded
socket outlet.
3.3.2 Speaker output hazard
PLMs are capable of producing hazardous
output voltages. To avoid electrical shock, do
not touch any exposed speaker wiring while the PLM
is operating. The external wiring connected to the
speaker terminals shall be installed by a qualied
person, or ready-made leads or cords of appropriate
capacity shall be used.
As the power output channels produce high
voltage, do not connect or disconnect speaker
cables when the mains power is on.
3.3.3 Radio interference
A sample of this product has been tested and complies
with the limits for the European Electro Magnetic
Compatibility (EMC) directive. This equipment has
also been tested and found to comply with the limits
for a Class B digital device, pursuant to Part 15 of
the FCC Rules. These limits are designed to provide
reasonable protection against harmful interference
from electrical equipment. This product uses radio
frequency energy and if not used or installed in
accordance with these operating instructions, may
cause interference to other equipment, such as
radio receivers. However, there is no guarantee
that interference will not occur in a particular
installation.
If this equipment does cause harmful interference to
radio or television reception, which can be determined
by turning the equipment on and off, the user is
encouraged to try to correct the interference by one
or more of the following measures:
Reorient or relocate the antenna.▸
Increase the separation between the equipment
▸
and receiver.
Connect the equipment to an outlet on a
▸
circuit different from that to which the receiver is
connected.
Check if the affected unit complies with the EMC
▸
limits for immunity, (CE-labeled). If not, address
the problem with the manufacturer or supplier.
All electrical products sold in the EC must be
approved for immunity against electromagnetic
elds, high voltage ashes, and radio inter-
ference.
Consult the dealer or an experienced radio/TV▸
technician for help.
3.3.4 Speaker damage
Your PLM Series device is very powerful and
can be potentially dangerous to both
loudspeakers and humans alike. Many loudspeakers
can be easily damaged or destroyed by overpowering
them. Always check the speaker’s continuous and
peak power capabilities. Although the PLM’s
attenuators can be used to reduce the overall gain,
an increase of the input signal can result in full output
power, which may cause damage to connected
speakers.
3.3.5 Maintenance
For safe and reliable operation, the dust covers behind
the front panel should be cleaned regularly. If the dust
filters are not maintained there will be safety risks.
For example the unit can ignite the dust and a fire
will occur due to high internal temperatures. There
is also a risk that the unit will malfunction since it is
dependent on constant airflow from front to rear. If
the dust filters are not clean and the unit malfunc-
tions, any resultant problems will not be covered by
the warranty.
8 PLM Series Operation Manual
4 WELCOME
4.1 Introduction
Thank you for choosing the Lab.gruppen PLM Series
of Powered Loudspeaker Management systems for
your sound reinforcement needs. We are condent
that you will be pleased with the performance, unique
features, conguration exibility, reliability, and long-
term durability offered by PLM Series products.
This manual (together with the companion manuals
dealing with software, networking etc.) provides a
comprehensive guide to the features and functionality
of the PLM Series of Powered Loudspeaker
Management systems. Please read them through
thoroughly to become fully acquainted with the many
conguration and control options available in PLM
Series products . Most features are accessible either
via the intuitive front panel interface or remotely,
with the included Dolby Lake Controller PLM Edition
software package.
To facilitate timely installation and use of this PLM
Series product you will nd,as a part of the PLM
Series welcome package that came with the product,
the PLM Series Quick Start and Field Reference
Guide (QS&FRG). The PLM Series QS&FRG contains
the basic information needed to safely install a PLM
system and place it in service.
We do, however, highly recommend reading through
all manuals in their entirety. As you become thoroughly
familiar with all aspects of the PLM Series, you may
learn about features and options that will affect your
choices of operational modes or loudspeaker system
congurations.
The Lab.gruppen PLM Series utilizes proven Dolby
Lake Processor technology and expands upon it,
providing a suite of load verication and performance
monitoring features. The power amplication section
builds on the foundation of the road-tested FP+
and legendary fP Series, providing the same sonic
signature – powerful, tight bass and transparent
high frequency response. In addition, the PLM
Series establishes new benchmarks for high power
and channel density in tandem with digital signal
processing, system management, and protection
features found in no other product.
Thank you again for placing your condence in
Lab.gruppen products.
4.2 Main Features
The PLM Series incorporates a number of sophisticated
technologies to ensure the best possible performance
and many years of reliable operation. The following
section summarizes the benets of each feature,
and gives a reference to the corresponding section
in this or other manuals.
4.2.1 Amplier platform
The PLM Series amplier section is built on the
foundation of Lab.gruppen’s robust, road-proven
FP+ Series. Features in common with the FP+ Series
include extraordinary power density, patented Class
TD® output stages, Regulated Switch Mode Power
Supply (R.SMPS™), the high-efciency Intercooler®
copper-nned cooling system, and a full suite of
protection features. Signal inputs are analog, AES
digital, and a digital audio network; loop-through
outputs or redundant pairs are provided for each
input type. (See section 6.2.)
4.2.2 Amplier DSP: Gain, ISVPL, load
verication and performance monitoring
Input gain (sensitivity) is set in the digital domain in
the PLM Series, controllable through the DLC PLM
Edition software or the front-panel interface. The
DSP-implemented Inter-Sample Voltage Peak Limiter
(ISVPL) tailors each output to the characteristics of
the connected load. (See section 7.3.1.)
The on-board DSP also implements a comprehensive
set of tools for load verication and real-time
performance monitoring. These functions utilize
LoadLibrary, a comprehensive database for each
loudspeaker component of the connected load
(usually one or more band-limited drivers in a multi-
way system). Using this data and a brief test signal,
LoadSmart then compares actual-to-predicted
response, identifying any malfunctioning components
or connection errors. During the actual performance,
SpeakerSafe™ monitors real-time load status,
including amplier, loudspeaker voice coil and magnet
temperatures; this allows operators to avoid power
compression and identify potential problems. (See
Dolby Lake Controller User Manual PLM Edition
Addendum for more detailed information on PLM
Series load verication and real-time performance
monitoring functions.)
PLM Series Operation Manual 9
4.2.3 Dolby Lake Processing and Controller
The PLM Series integrates seamlessly into the
Dolby Lake processing environment. Two processing
modules offer precise settings for gain, delay,
crossover slope, equalization and limiting. Dolby Lake
processing features incorporated in each module
include Raised Cosine Equalization, linear phase
crossovers and LimiterMax™ loudspeaker protection.
The Super Module feature allows hardware processing
modules in two or more separate PLM Series units
to function as a single module in the Dolby Lake
Controller PLM Edition software interface. (See
section 8.2 and the separate Dolby Lake Controller
User Manual.)
4.2.4 SmaartLive integration
The Dolby Lake Controller PLM Edition enables
seamless, plug-in integration of the industry-standard
SmaartLive analysis system. With this feature,
operators can measure with SmaartLive and make
EQ adjustments at the same time, using the same
software controller on a Wi-Fi enabled Tablet PC.
(See the separate Dolby Lake Controller User
Manual.)
4.2.5 Dante audio network
All PLM Series products include Dante digital
audio networking as standard. Based on the latest
advances in networking, Dante offers simplied
system conguration and extremely low latency
while delivering very high quality uncompressed
digital audio over the entire PLM Series network.
The Zen™ automatic conguration feature enables
“plug-and-play” setup without third-party DHCP or
DNS servers. Dante is fully compatible with new
high-bandwidth network backbones, allowing high
channel counts while also transporting third-party
control protocols through the same network.
WELCOME 4
10 PLM Series Operation Manual
The PLM Series products have no top or bottom
vents; PLM’s may be stacked directly on top of each
other. It may be desirable to include a 1U spacer
between PLMs to permit more convenient rear panel
wiring.
5.3 Rear Mounting
Two rear support brackets, plus mounting
hardware, are included with the PLM (gure 5-1).
It is recommended that these are used wherever
possible. They should be tted to vertical rack rails
at the rear of the rack. Refer to gures 5-2 and 5-3
for details of their installation.
Note that the support brackets are reversible and
may be tted to point either to the front or rear of
the rack. The orientation used in a particular situation
will depend on the depth of the rack.
x2
x2 x2x2
Figure 5-1
Two mounting methods are possible; note that
Method 1 additionally provides extra security against
unauthorized removal.
5 INSTALLATION
5.1 Unpacking
Carefully open the shipping carton and check for any
damage to the PLM Series product or the supplied
accessories. Every Lab.gruppen product is tested and
inspected before leaving the factory and should arrive
in perfect condition. If any damage is discovered,
please notify the shipping company immediately.
Only the consignee may initiate a claim with the
carrier or their insurers for damage incurred during
shipping. Save the carton and packing materials for
the carrier’s inspection.
In addition to the PLM, the shipping carton should
contain the following items:
PLM Series Network Conguration Guide▸
AC mains lead (power cord)▸
Rear brackets for additional rack support (pair)▸
Mounting hardware for above▸
CD-ROM containing:▸
PLM Series Quick Start and Field Reference Guide*
Dolby Lake Controller PLM Edition software*
PLM Series Operation Manual*
Dolby Lake Controller User Manual*
Dolby Lake Controller User Manual PLM Edition*
Addendum
We recommend that you keep the original carton and
all other packaging materials to facilitate shipping of
the PLM should the need arise.
5.2 Mounting
Airow for cooling the PLM is from front panel
(intake) to rear panel (exit). Therefore there must be
nothing at the front or rear of the rack in which the
PLM is mounted – such as doors or lids - to impede
the airow.
Note that there must always be sufcient space at
the rear of the PLM to permit efcient air exit (see
section 5.4) and to accommodate rear connectors
and cables; allowance must be made for cable or
loom bends within a rack. In particular, the mains
cable (AC cord) and its Neutrik PowerCon connector
require at least 12 cm (4.75 inches) clear rack depth
behind the PLM rear panel.
PLM Series Operation Manual 11
For situations where rapid removal and replacement
of units is of paramount importance, Method 2 may
be used as it does not involve any permanently
secured fixing at the rear of the unit.
Method 1:
Use washer for xed installation.
Figure 5-2
Method 2:
Use tube for slide-on installation.
Figure 5-2
5.4 Cooling
The PLM uses a forced-air cooling system with
airflow from front to rear, allowing high continuous
power levels without thermal problems. (Front-to-rear
airflow is preferable as air at the front of a rack is
cooler than that at the rear in nearly all situations.)
Never attempt to reverse the airflow. The operation
of the PLM’s cooling system is dependent on front-
to-rear airflow; it will not function effectively with
airflow in the opposite direction.
Make sure an adequate air supply is provided in
front of the PLM, and that the rear of the PLM has
sufficient space to allow the exit air to escape. If the
PLM is rack-mounted, never operate the unit with
any front or rear rack doors or covers in position.
Also note that any unused rack spaces should have
solid blanks fitted (not ventilation blanks) to ensure
efficient air circulation. Leaving gaps in between
items of equipment degrades the effectiveness of
forced-air cooling.
If installing one or more PLM’s in a rack with other
fan-cooled equipment, be sure that all the other
units also use front-to-rear airflow for cooling. If
this precaution is not observed, there is a risk of
overheating, as units with the reverse airflow will
be drawing in air which has already been heated by
the PLMs units.
The PLM is equipped with a sophisticated
temperature sensing system which protects
it from any overheating which may occur
as a result of inadequate ventillation. Should
a power output channel overheat, the temperature
sensing circuits will mute that channel until the
temperature reduces to a safe level. If the power
supply overheats, another sensing circuit will mute
all channels until the power supply temperature
reduces to a safe operating level.
Always make sure that the dust filters behind the
detachable front panel are clean to ensure maximum
possible airflow.
If the device malfunctions as a result of
dirty dust lters, any required repairs are
not covered by the warranty.
INSTALLATION 5
12 PLM Series Operation Manual
5.5 Operating voltage
The label adjacent to the mains (AC) input
connector indicates the AC mains voltage for
which the amplier is wired and approved. The
amplier is built in two versions: 115 V and 230 V.
Connect the mains cable (AC cord) only to an AC
source of the voltage shown on the label.
Any damage resulting from a PLM Series
product being connected to an AC source
of incorrect voltage will not be covered by
the warranty.
The PLM uses primary switching, which means the
mains power is rectied on the primary side of the
transformer. This makes the power supply insensitive
to mains frequency variation, and it will operate
normally on line frequencies from 45 to 75 Hz.
If the mains plug (AC plug) tted to the mains cable
(AC cord) is not appropriate for your country, it can
be removed and a locally-sourced one tted instead,
observing the following color coding:
230 V versions 115 V versions Connect to
BROWN BLACK LIVE
BLUE WHITE NEUTRAL
GREEN/YELLOW GREEN EARTH (GROUND)
Table 5-1
If you are not 100% condent of your compe-
tence to replace the mains plug (AC plug), the
task should be carried out by qualied personnel.
Once a suitable AC supply is connected, the PLM
can be turned on using the front panel power switch.
When the unit is switched on, the PLM goes through
a soft-start sequence as it performs a diagnostic
routine on the internal circuitry. The fans will run at
high speed for a short period before dropping to idle
speed, and the power symbol in the power switch will
change from red (Standby mode) to green (active).
In-rush current is controlled and limited during
the soft-start sequence, enabling multiple
PLMs on the same AC mains circuit to be
powered up simultaneously.
5.6 Grounding
Analog inputs feature the Iso-Float ground isolation
system. Iso-Float technology combines the benets
of transformer-coupled isolation with the advantages
of clean, direct-coupled inputs. Iso-Float provides a
cost-effective alternative to isolation transformers for
avoiding ground loops.
The audio converters are galvanically isolated, and
not connected to the main ground. High-speed
transformers and opto-isolators create a barrier
between the PLM and the outside electrical
environment.
Iso-Float may be disabled via the supplied
Dolby Lake Controller PLM Edition software,
or via the PLM’s front panel menu sys-
tem.
In the interests of safety, NEVER disconnect the earth
(ground) pin on the mains cable (AC power cord).
Use correctly-shielded balanced audio input
connections to minimise hum and interference. Refer
to section 10.2.1 for more information.
5 INSTALLATION
PLM Series Operation Manual 13
6 QUICK GUIDE OVERVIEW
The PLM’s front panel is based around a 2.5” daylight-
readable 128 x 128 pixel backlit liquid crystal display
(LCD), through which control and monitoring of most
of the PLM’s functions are performed via a simple
menu system. Controls are grouped in two switch
clusters alongside the display; these include a number
of dedicated-function keys (such as METER and
MENU), eight “soft” keys (functions vary according
to the current display page), and a data entry wheel
(rotary encoder).
Handles
Two sturdy metal handles are tted to the front panel.
The handles always should be used when carrying
the PLM and tting it in or removing it from a rack.
Ensure that any door or removable rack front cover
has sufcient depth to clear the handles.
Dust Filters
Two dust lters are tted behind metal covers. To
remove the covers, loosen the thumbscrews located
behind the front handles. Once detached, the dust
lter elements can be removed for cleaning. See
section 12.2 for information on cleaning the dust
lters.
The device never should be operated
without the dust lters in place.
6.1 Front Panel overview
Display
The display will illuminate when the PLM is active.
Many of the traditional controls, and displays found on
conventional ampliers are replaced on the PLM by a
simple set of on-screen “pages”, which allow all PLM
operating parameters to be monitored and controlled.
PLM functions are controlled with the eight “soft”
keys immediately adjacent to the display, together
with the single rotary encoder knob. Primary fault and
status indications are given by multicolor LEDs.
The display is protected by a tough, transparent
plastic lm, which may be cleaned with a soft cloth;
solvents should not be used.
The layout of various display “pages” is standardized
to a high degree for ease of use. In general, each
page is divided into two columns of four blocks,
with the left-hand column referring to inputs and
the right-hand to outputs. Each block has four rows
of data, which can be either alphanumeric or in the
form of a bargraph meter.
Comprehensive details of the various display pages
and the associated controls are given in section 9 –
Front Panel Interface.
Standby
The PLM is powered on and off by the top left-most
button, STANDBY. See Dolby Lake Controller User
Manual PLM Edition Addendum (sections 5.3.1
and 5.7) for further information regarding local and
remote power control.
PLM SERIES
3
4
5
67
8
9
10 11
12
1 1
2 2
Figure
6-1
14 PLM Series Operation Manual
QUICK GUIDE OVERVIEW 6
Mute Enable
Select MUTE ENABLE to allow muting via the soft
button of the inputs to the Dolby Lake system, the
power output channels, or both. The MUTE ENABLE
legend in the button ashes when the mode is
selected. A second press will deselect the mode;
however, if left active, MUTE ENABLE mode will
automatically cancel after two minutes if no further
mute actions are taken.
Meter
The METER button scrolls through three alternative
views: HOME, MODULE, and TEMPERATURE.
Pressing METER when in MENU mode returns the
screen to METER mode, and the HOME view is
displayed.
The display has two basic operating
modes: METER (default) and MENU.
Menu
Pressing the MENU button puts the screen display
into MENU mode, and the “top” page of the MENU
“tree” is displayed. Once in MENU mode, most of
the PLM Series’ operating functions can be accessed.
See sections 9.12.2 to 9.12.8 for more details.
Soft function buttons
Eight soft function buttons are set adjacent to
the display in two groups of four. These buttons
are unlabelled because their functions change
according to the current menu mode as displayed
on the screen.
Status LEDs
Eight tricolor LEDs are integrated into the soft buttons
for convenience. These convey both fault and warning
indications, plus the currently selected mute status
of the Dolby Lake Processing system inputs and
the output channels. Full details can be found in
section 9.10.
High-intensity LED
A white, high-intensity LED is located to the right
of the display. This LED illuminates when the PLM
Series’ control system is being accessed remotely
via the DLC PLM Edition software.
Encoder
The rotary encoder is used to modify various PLM
parameters (e.g. input level) in conjunction with the
various display pages. When a menu item is selected
that permits adjustment of parameter values, the ring
around the knob illuminates.
Exit
The EXIT key is used primarily while navigating the
menu system in MENU mode; pressing it takes the
display back to a previous screen (“up one level” in
the menu tree). In METER mode, pressing the EXIT
key always returns the display to the HOME view.
PLM Series Operation Manual 15
6 QUICK GUIDE OVERVIEW
See section 10 for full details of
connector pinouts, etc.
6.2.1 Input connectors and Links
Analog inputs
Analog inputs are available on two standard XLR3F
latching connectors. The inputs are electronically
balanced using Dolby’s patented Iso-Float circuitry.
The impedance is 20 kOhms, and the inputs can
accept a maximum input level of +26 dBu.
Analog links
Two latching XLR3M connectors are tted adjacent
to the analog input connectors. These are paralleled
to the input connectors to provide an analog
loopthrough to feed additional PLM Series units, or
other equipment.
AES/EBU inputs
A latching XLR3F connector is provided which accepts
an AES/EBU digital audio signal. Input impedance is
110 ohms.
Note that the AES/EBU digital audio format is two-
channel, and thus both PLM inputs are fed via a
single connector. Selection of the analog or digital
inputs is made via the front panel display or control
software.
In comparison to analog signals, digital audio
signals such as AES/EBU require quite
different cabling and routing techniques. In
particular, standard XLR “mic cables” - even
high-quality ones - are rarely suitable for digital audio.
Always use 110 ohm digital audio cables. NEVER
CONNECT A DIGITAL AUDIO SOURCE TO AN
ANALOG INPUT, OR VICE-VERSA. Always use the
correct type of cable and connectors for the two
different types of signals. If you are unfamiliar with
digital audio transmission techniques, seek guidance
from authoritative references or qualied personnel
before attempting to interconnect equipment in the
digital domain. See section 12.5 for further
information.
AES/EBU link
A latching XLR3M connector is tted adjacent to the
AES/EBU input connector. This is paralleled to the
input connector to provide an AES/EBU loop-thru
to feed further PLMs, or other equipment. An AES/
EBU 110 ohm termination load can be enabled, via
the front panel menu, when the PLM is the last
unit connected within an AES/EBU daisy-chained
system.
6.2.2 Output connectors
The PLM is available with a choice of output
connectors for power outputs: binding posts or
Neutrik Speakon.
The PLM is capable of bridge-mode
operation, however the present system
management software does not support
this mode and therefore bridged operation
is NOT recommended.
Please contact plmsupport@labgruppen.com for
further information on bridge-mode operation.
6.2 Rear Panel overview
Ser. N:o
Removed!
CH 2
CH
CH 4
CH 3
CLASS 2 WIRING
SPEAKER OUTPUTS
INPUT
INPUT 2LINK
LINK 2
AES/EBU
INPUT 1-2 LINK 1-2
LINK SECPRIMACT LINKACT
SWITCHED 10/100 Base-TX
Must be grounded/earthed
Made in Sweden
PIN 1: SCRN 2: POS 3: NEG
ANALOG WITH
I
SO-
F
LOAT
TM
200/240V 2500W
50-60Hz
PLM
0000Q
1
Ser. N:o
Removed!
CLASS 2 WIRING
SPEAKER OUTPUTS
INPUT
INPUT 2LINK
LINK 2
AES/EBU
INPUT 1-2 LINK 1-2
LINK SECPRIMACT LINKACT
SWITCHED 10/100 Base-TX
Must be grounded/earthed
Made in Sweden
PIN 1: SCRN 2: POS 3: NEG
ANALOG WITH
I
SO-
F
LOAT
TM
1+/- CH 1+/-
2+/- CH 2+/-
1+/- CH 1+/-
2+/- CH 2+/-
3+/- CH 3+/-
4+/- CH 4+/-
1+/- CH 3+/-
2+/- CH 4+/-
200/240V 2500W
50-60Hz
PLM
0000Q
1
1234
5
6
789
12
Figure 6-2
16 PLM Series Operation Manual
6 QUICK GUIDE OVERVIEW
Binding posts
In this version, the power outputs for loudspeaker
connection are available on four separate pairs of
fully-enclosed binding posts.
Speakon connectors
In this version, the power outputs are simultaneously
available on a single 8-pole Neutrik Speakon
connector, and on two 4-pole Neutrik Speakon
connectors. The two 4-pole connectors carry the
outputs of channels 1 & 2 and 3 & 4 respectively.
The gure below shows the proper wiring scheme
for these Speakon outputs.
Pin
No.
NL4 #1 Chs.
1 & 2
NL8 Chs.
1 - 4
NL4 #2 Chs.
3 & 4
1+ Ch. 1 o/p + Ch. 1 o/p + Ch. 3 o/p +
1- Ch. 1 o/p - Ch. 1 o/p - Ch. 3 o/p -
2+ Ch. 2 o/p + Ch. 2 o/p + Ch. 4 o/p +
2- Ch. 2 o/p - Ch. 2 o/p - Ch. 4 o/p -
3+ Ch. 3 o/p +
3- Ch. 3 o/p -
4+ Ch. 4 o/p +
4- Ch. 4 o/p -
6.2.3 Network connectors
The two Neutrik RJ45 EtherCon®connectors
permit integration into an Ethernet control network
encompassing multiple PLM Series units as well as a
PC running the DLC PLM Edition software. Network
connection permits full control of all PLM functions,
and monitoring of all PLM operating parameters, from
a remote position. The PLM Series also supports
the Dante audio networking protocol, which allows
transmission of multichannel, high-denition digital
audio over the same Ethernet connection.
6.2.3.1 10/100Base-T network
The Ethernet ports automatically switch to operate
at the two standard Ethernet data rates of 10Base-T
and 100Base-T, and also allow either “crossed” or
“straight” network cables to be used. Two LEDs
above each port indicate connection to a valid network
(LINK) and network activity (ACT).
Full information on how to connect the PLM to a
network is contained within a separate document ,
the PLM Series Network Conguration Guide.
Primary connector
Use this connector when the network is a simple
“star” conguration, consisting of individual Cat-5e
connections between PLMs and a local Ethernet
switch. Alternatively it can be used to connect to
the Secondary connector of another PLM within a
network, thus forming a daisy-chain topology. Further
information on PLM network congurations can be
found in the PLM Series Network Conguration
Guide.
Secondary connector
The secondary network connector can be used as a
loop-through to daisy-chain multiple PLMs into the
network. Alternatively, system security can be greatly
increased by using a dual-network topology. In this
case, the Secondary connector is connected to an
alternative Ethernet distribution system employing
a second set of switches, thereby ensuring full
redundancy and no single point-of-failure in the case
that Dante is used and a switch or cable fails. Further
information on PLM network congurations can be
found in the PLM Series Network Conguration
Guide.
Mains connector
AC input to the PLM is via a Neutrik PowerCon
connector, rated at 32 A.
PLM Series Operation Manual 17
6 QUICK GUIDE OVERVIEW
The Dolby Lake Controller PLM Edition software is
easily installed by inserting the CD in the computer’s
CD drive and allowing the auto-setup routine to
run. Select INSTALL then Dolby Lake Controller
software from the installation window to initiate
installation. For most installations, the subsequent
suggested default paths can be accepted.
Please note that, if pre-existing DLC presets
are present on your PC when you install the
DLC PLM Edition software, choosing a
specic installation path may be preferable.
See the DLC User Manual PLM Edition Addendum
for more information.
Refer to chapter 2 of the DLC User Manual for further
details on how to install the software and congure
your computer for optimum performance.
Minimum recommended computer specications
are:
Intel® Pentium® 866 MHz or faster.▸
256 MB RAM or greater.▸
64 MB Video RAM or greater.▸
Windows XP.▸
DirectX® 8.1 or higher (pre-installed with
▸
Windows XP).
100Base-T wired Ethernet adapter and/or 802.11g
▸
wireless Ethernet adapter.
XGA display screen with min. resolution of 1024
▸
x 768 pixels.
If you are unsure about installing new software on
a PC, please contact your organisation’s IT Dept., or
another suitably qualied specialist rst.
Once the software is installed, the application can be
launched by clicking the desktop icon created during
the install process in the usual way.
Full details of how to use the software application
are contained in the documents DLC User Manual
and DLC User Manual PLM Edition Addendum,
both of which are supplied with the PLM.
6.3 Integrated Dolby Lake
Processing
As outlined in Section 4, PLM Series products
contain a fully integrated Dolby Lake loudspeaker
management system, providing many of the features
available as standard in the Dolby Lake Processor
(DLP) stand-alone unit. The Dolby Lake system within
the PLM provides fully-programmable crossovers,
EQ, dynamics and other functions, and is controlled
via the supplied DLC PLM Edition software. (See
section 6.3.1.) Additionally, some functions of the
Dolby Lake system can be accessed from the PLM’s
front panel screen.
Setting up the integral Dolby Lake system via the
DLC PLM Edition software includes selecting the
basic PLM conguration, including input mixers, input
format (analog or digital, etc.), crossover conguration
and output routing.
A full description of how the DLC PLM Edition software
is used with the PLM is contained in the separate
document (supplied on CD-ROM with the PLM): DLC
User Manual PLM Edition Addendum
Also see accompanying document, the PLM Series
Network Conguration Guide for details of how to
connect one or more PLMs to a PC via a network.
6.3.1 Dolby Lake Controller PLM Edition
The CD-ROM supplied with the PLM contains the
Dolby Lake Controller PLM Edition software package.
This should be installed on any PC(s) that are to
be used to control and monitor the PLM(s). In a
touring situation where multiple networked PLMs
are involved, this will generally be a Tablet PC.
Figure 6-3
18 PLM Series Operation Manual
7 OPERATION AND PERFORMANCE
7.1 Introduction to Operation
This chapter provides comprehensive information
on PLM Series connection, setup, operation and
performance. The detailed information included here
is essential to realizing the full functionality of the
PLM Series.
7.1.1 Operation precautions
Make sure that the Standby button on the PLM’s
front panel is either unlit, or is showing red (i.e., the
PLM is in STANDBY mode), before making any input
or output connections.
Make sure that the AC voltage is correct and
matches that printed on the label adjacent to
the AC mains connector.
Make sure that no signal is present at the input to the
PLM when powering it up to prevent any inadvertent
bursts of high level audio.
7.2 Power Output Performance
The PLM uses Lab.gruppen’s patented Class TD
technology in the output stages, which couples the
efciency of Class D topologies to the sonic purity
of Class B designs.
The primary benet is that Lab.gruppen’s Class
TD works perfectly under all load conditions. The
output maintains its at frequency response even into
complex loads with very low nominal impedances.
Reliability is very high, and there is no interference
with nearby RF equipment. Superior efciency allows
greater power density while minimizing cooling
requirements, yet sound quality matches that of
the best Class B designs.
7.2.1 Symmetrical Power
The example PLM 10000Q can deliver power as per
Table 7-1 when all four channels are driven equally.
Load
Impedance
(ohms)
2.0 2.7 4 8 16
Max.
Output
power
(Watts)
2350 2700 2300 1200 660
Table 7-1
7.2.2 Asymmetrical power
The example PLM 10000Q can deliver power as per
Table 7-2 when two channels are driven 3 dB lower
than the other two.
Table 7-2
7.2.3 Power over time
Power ratings given above are applicable to the
example PLM 10000Q running at these levels for a
period of 60 minutes. Due to thermal considerations
in the power supply and elsewhere, it is possible
to draw higher power levels for a shorter period
of time. The graph below illustrates how the rated
power gures are derived and the higher short-term
capability.
Peak output voltage at “max power burst”
Figure
7-1
Load
Impedance
(ohms)
2.0 2.7 4 8 16
Max.
Output
power
(Watts)
2350 2900 2400 1200 660
PLM Series Operation Manual 19
OPERATION AND PERFORMANCE 7
Power ratings are based on a “real-life” duty cycle of
25 ms full power every 400 ms. Between bursts, a
lower signal level applies, such that the continuous
average power is 1/8th of the rated power.
In reality, when some channels are delivering less than
maximum rated power, energy reserves in the PSU
are available to permit other channels to deliver more
power. The graph shows the peak output voltage over
time for a continuous sine wave is applied.
If all four channels are driven with the same signal
into the same impedance (solid red line), then the rail
voltage (dotted red line) will drop faster than when two
channels are delivering “max power” (solid blue line)
and two channels are delivering “half power” (solid
orange line). This is termed asymmetric loading. The
rail voltage for this is the dotted blue line.
It can be seen that higher power output is available for
25 ms bursts with asymmetric loading.
7.3 Amplier and Load
Protection Systems
The PLM is equipped with a comprehensive set of
protection circuits. If operating conditions become
sufciently extreme that any of these circuits become
active, indication is provided by LEDs in one or more
soft buttons 5-8, together with adjacent warning text.
In addition to this, notication is also presented within
the Dolby Lake Controller PLM Edition software and
within system log les.
7.3.1 Inter-Sample Voltage Peak Limiter
(ISVPL)
The ISVPL is a high quality voltage limiter. Its purpose is
to ensure that the voltage at the output terminals never
exceeds the threshold which has been set. It operates
on two fundamental principles:
The signal is delayed slightly in order to allow
▸
the ISVPL to “look ahead” and reduce the gain
before any voltage in excess of the threshold can
appear at the output. This results in zero voltage
overshoot at the output.
The amplitude of the output signal “between”▸
digital samples is predicted. This permits the
ISVPL to respond to analog peaks that may occur
at the power output.
The table below represents the absolute maximum
output power that an individual PLM channel can
deliver at the given ISVPL setting and impedance
shown.
The formula for generating the value for a
desired power into a load is
Vpeak =
ZP2
The formula for calculating the power
for a given ISVPL setting is
P=
Z
Vpeak
2
2
where |Z| is the magnitude of the complex load
impedance in ohms.
Table 7-3
* Note that these ratings are limited by the CPL (Current
Peak Limiter) functions, not by ISVPL settings, due to
amplier channel current capacity
The ISVPL threshold may be set at any level between
17.8 V and 153 V (model dependent) via the PLM’s
menu system. (See Section 9.12.2.5.1 or the Dolby
Lake Controller User Manual PLM Edition Addendum
MAX. SINEWAVE BURST POWER (Watts)
Load Impedance
(ohms) 2.7 4 8 16
ISVPL SETTING
(V peak)
153 (max.) 3365* 2926 1463 732
150 3365* 2813 1406 703
121 2742 1830 915 458
101 1910 1275 638 319
83 1290 861 431 215
70 918 613 306 153
56 587 392 196 98
47 414 276 138 69
38 361 181 90 45
17.8 (min.) 79 40 20 10
20 PLM Series Operation Manual
7 OPERATION AND PERFORMANCE
for details.) Note that the maximum ISVPL setting
of 153 V is greater than the 150 V maximum peak
voltage available from the example PLM 10000Q.
Other models may differ. This is to accommodate
the small degree of production spread of maximum
output voltage that exists between PLMs. By
allowing a maximum ISVPL setting fractionally higher
than the maximum safe output voltage under any
condition ensures that severe clipping will never be
encountered.
7.3.2 Current Peak Limiter (CPL)
The output Current Peak Limiter (CPL) ensures that
the power output section will not be damaged by
forcing it to deliver current levels at the outputs that
exceed the maximum current ratings of the output
transistors. The CPL keeps the output transistors
within their Safe Operating Area (SOA).
The CPL is non-adjustable.
CPL activity is indicated by the affected output
channel LED (one of the four LEDs in the soft buttons
to the right of the display) ashing red together with
a CURRENT CLIP warning message displayed on
the screen adjacent to the LED. A warning is also
displayed on the controlling PC via the network.
This condition indicates an attempt to draw excessive
current at the output. The output is attenuated until
the output current falls below the maximum current
rating. (See section 13 Technical Specications for
further details concerning ratings.)
If this fault condition is indicated, check the
output cables and examine the state of the
loudspeaker. If there appears to be a normal
impedance present, it may be possible to
rectify the condition by altering the ISVPL settings
or lowering the input levels. CPL operation may also
be occasioned by too low an output impedance, as
would be caused by too many loudspeaker cabinets
in parallel.
7.3.3 Power Average Limiter (PAL)
The Power Average Limiter (PAL) controls the AC
current into the power supply. Power consumption
is limited to the rated design parameters of the
power supply, ensuring that the PSU will never be
overloaded. Also, high power products such as those
in the PLM Series can potentially draw more current
(with output devices still within safe operating areas)
than is allowed by the mains fuse
Only the 230 V version is tted with a fuse.
It is not possible to source fuses with sufcient
current capacity for the 115 V versions.
The PAL protection feature can help prevent the
supply’s external breaker from tripping within time
intervals of less than three minutes. For longer time
intervals, it is the responsibility of the user to ensure
that the average level of the audio is within limits that
ensure that the breaker doesn’t trip.
PAL activity is indicated by the LED within the rst soft
button adjacent to the display ashing red, together
with a PAL ACTIVE warning message displayed on
the screen. A warning is also displayed on the DLC
PLM Edition software.
7.3.4 Current Average Limiter (CAL)
The Current Average Limiter (CAL) monitors the RMS
current drawn from each output channel to ensure
that the power output stages are not overloaded.
When activated, it regulates the current to a safe
level to protect the channel. The CAL should not be
activated in normal usage, but if it is, its operation
is indicated by an active LED and the message CAL
ACTIVE. Futher indication is given within the DLC
PLM Edition software.
7.3.5 Voltage Clip Limiter (VCL)
If current draw from the PLM’s power supply is
too high, the PSU’s regulation capability may be
exceeded and the internal voltage rails may drop.
This can cause clipping; if this occurs the Voltage
Clip Limiter acts rapidly to prevent clipping occuring
on the subsequent peaks.
7.3.6 Temperature Protection
Thermal measurements are made at several points
within each channel as well as on the power supply.
If the maximum permitted temperature is exceeded,
a high temperature warning is given. In the case of
an amplier component overheating, this will be
indicated by one of the output channel LEDs (in the
right-hand soft buttons) showing steady red. The
adjacent fault message will show TEMP FLT:CH. In
the case of the PSU overheating, the fault is indicated
by the top left soft button’s LED turning steady red,
and the adjacent on-screen text displaying the fault
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