CIE-Group MPS1, User Instructions

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4
Description:
• Control In:
The CONTROL input requires switch
closure across the terminals P.T.T. (Press
To Talk) & 0V to activate zone control.
The switch will normally be a zone
select switch in a microphone console.
When activated three DPCO relay (RL1,
RL2, RL3) circuits will be energised
simultaneously, viz.: zone control, signal
muting and switched 24v DC out.
• Zone Control:
The zone control section consists of a
DPCO relay (RL3) which is activated by
switch closure across the ‘Press To Talk’
(P.T.T.) terminals. The main 100v speaker
line signal, zone 1, is connected to the
MAIN AMP IN terminals which are directly
connected on the printed circuit board to
the MAIN SPEAKER OUT terminals, i.e.
unswitched. The MAIN AMP IN terminals
are also connected to the Normally Open
contacts on the relay. When the relay is
activated, the main amplifier signal is
routed to the switched speaker output
terminals (SW SPEAKER OUT) as well as
the MAIN SPEAKER OUT terminals.
The AUX AMP IN terminals are connected
to the Normally Closed contacts on the
relay and allow a second amplifier, zone
2, to be connected. When the relay is
relaxed (de-energised) the AUX AMP IN
terminals are connected through to the
SW SPEAKER OUT terminals. An LED
adjacent to the relay illuminates when
the relay is activated, giving a visual
indication of its operation.
• Signal Muting:
A signal muting facility is supplied,
consisting of a DPCO relay (RL2) which
is activated by switch closure across
the ‘Press To Talk’ (P.T.T.) terminals. All
the contacts of the relay are brought out
to the SIGNAL MUTE terminal group.
The actual muting can be achieved in
several ways depending on the system
requirements, although typically the
signal (from tuner, tape deck, etc.,) would
be connected to the common terminal
(+ SIG OUT) and the ground or screen
to the normally open terminal (SCREEN).
When the mute relay is activated the
contacts close and the signal is short
circuited. It is important to check that the
source from the tuner, tape deck, etc.,
is suitably buffered so that shorting out
the signal will not damage the source.
If in doubt, the relay contacts should be
configured to open circuit the signal to
the amplifier.
As there are two sets of contacts
available, several muting arrangements
are possible. These include muting
balanced signals, muting two separate
signals, using one set of terminals to
trigger a chime.