C Series C 20:8X, C 10:8X, C 10:4X and C 5:4X Operation Manual
19
To configure an individual output channel for a
constant voltage system, you simply adjust the
DIP-switches to the desired voltage. However,
when using an output for a low-impedance system
( 4, 8 or 16 ohms), then sometimes you need to
adjust the VPL to a lower setting to avoid either
delivering excessively high continuous power to the
speaker or overheating of the output channel through
high current draw. For example, with a very “hot”
continuous output signal, the temperature could rise
to a critical level and activate Temp warning or even
Temp Mute. Lowering the VPL setting usually will
solve this situation.
If the Current Peak Limiter is active or indicates low
impedance, lowering the VPL setting can rectify this
situation as well.
7.4.6 Constant Voltage 70 V and 100 V systems
setup and operation
When using C Series amplifiers to drive constant volt-
age (high-impedance) speaker systems at 70 Vrms or
100 V peak, you can in most cases simply connect
the speakers to the amplifier output terminals, select
the correct VPL setting, and place the amplifier in
service.
7.4.7 Output Current Peak Limiter (CPL)
The Current Peak Limiter (CPL) ensures that the
amplifier will not be damaged by trying to deliver cur-
rent to the outputs exceeding the physical limitations
the transistors. The CPL keeps the amplifier within
the Safe Operating Area. The CPL is non-adjustable
and has different limit values depending on model
type. The maximum output current values for the
four C...X models are:
C 20:8X, 8 Arms per channel
•
C 10:8X, 5.6 Arms per channel
•
C 10:4X, 8 Arms per channel
•
C 5:4X, 5.6 Arms per channel
•
CPL activity is indicated by illumination of an orange
LED for each channel on the front-panel. Warnings
also are shown in the DeviceControl software’s
GUI.
A steadily illuminated orange CPL LED indicates a
short circuit situation (or very-low-impedance). The
output will mute for 6 seconds before measuring
the output impedance again. This will continue until
the short circuit is fixed, at which time the output
will automatically un-mute. An input signal must be
present to allow detection of short circuit or low-
impedance conditions.
If the CPL LED is steadily illuminated orange
while the output is muted and the -4 dB
signal LED is NOT on, then the amplifier
output is detecting a short circuit or low
impedance condition. The problem can be solved by
checking input and output cables and examining the
state of the loudspeaker load. If there is no short
circuit present, then the condition may be rectified
by lowering the VPL or input levels.
If the CPL indicator is lit continuously, then the ampli-
fier is delivering excessive current and is being forced
into a current limiting state (output muted).
7.5 GPIO connection and opera-
tion
7.5.1 Introduction
C…X amplifiers provide extensive GPIO (General
Purpose Input / Output) facilities for interfacing with
third-party systems for AV control and power se-
quencing. GPIO functions are accessed through
two-pole Phoenix connectors and DIP-switches on
the rear panel.
7.5.2 General Purpose Outputs (GPO)
Two GPOs are provided, with connectors labeled
ON (GPO 1) and FAULT (GPO 2). Both operate using
internal relays which are designed to respond to
external contact closures.
The GPO 1 (ON) is open when the amplifier power
is off. The GPO 1 relay closes when the amplifier
power is turned on, either from the front panel or
remotely using NomadLink or the GPI (General
Purpose Input).
The GPO 2 (FAULT) relay is open when the amplifier
is operating normally. The relay closes when the
amplifier reports any Fault condition, such as VHF,
DC or TEMP. See section 7.6.
OPERATION AND PERFORMANCE 7