actually used. The XB4 pin must be con-
nected in the same manner as SB pins (mas-
ter to each of its slaves). The XB4 line serves
as an acknowledgment line for the parallel
data bus.
N. SB Ground
A 4-pin mini-barrier block connector is pro-
vided as a digital ground for slave bus refer-
ence. SB Ground must be tied together from
a master to each of its slaves for proper digi-
tal ground reference on the Slave Bus.
Digital Communication
The form of communication available be-
tween master MRX units and other IQ Sys-
tem components is the Crown Bus. The
Crown Bus is a communication standard for
serial transmission of IQ command protocol.
It normally operates on a simple two-wire 20
mA current loop (fiber optic optional). See
also item J. When operating on a Crown Bus
loop, a system interface is required for com-
munication with a computer. A Drone can also
be used to manipulate MRX modules. A spe-
cial slave bus is used between a master unit
and up to 31 slaves. This is a ten wire system
including SB1-8, XB4, and SB Ground. The
slave bus is a parallel communication me-
dium allowing the processor on a master unit
to take direct control of slave unit functions.
Applications
MRX-24/24S IQ Matrixers can serve a vari-
ety of very powerful functions. You custom-
ize operation, tailoring it to the system require-
ments.
MRX-24/24S units can function in a
variety of matrix formats. Individual relay
groups can function as 6x1, 1x6, or can sim-
ply be viewed as a group bus which any of
seven lines—six switched and one
unswitched common—can tie into. Four of
these groups are present on a single
MRX-
24/24S module.
It can switch low power loads such as light-
ing, fan, and motor controls, low DC and AC
power, and all types of audio and digital elec-
trical signals. The
MRX-24/24S can even
switch relatively low power
speaker lines, including 70V dis-
tribution and routing.
Besides easy routing of bal-
anced audio, the MRX-24 makes
it easy to perform current moni-
toring operations, either with in-
dividual speakers or in groups.
This is done by adding small re-
sistances to the speaker lines,
then using the
MRX-24/24S to
control which speaker
line(s) will be monitored.
An IQ
SMX-6
™
sensing
mixer/multiplexer moni-
tors whichever speaker
line is routed to it by the
matrixer.
For applications where
higher voltages or cur-
rents are being
switched, the
MRX-12
or
MRX-12S is recom-
mended.
Additional Electrical
Specifications
Protection:
The MRX
units use dr y contact
relays with no other in-
line electronics. For pro-
tection, power
circuits con-
trolled by
POWER
SUPPLY
BATTERY
BACKUP
(MEMORY)
AUX PORT &
CROWN BUS
POWER
DSPI
1 2 3 4 5 6 7 8
IQ ADDRESS
MICRO-
PROCESSOR
DECODER
+12 V
GND
RELAY
DRIVERS
SLAVE BUS
1 2 3 4 5
BOARD
ADDRESS
1A
1B
2A
2B
3A
3B
4A
4B
5A
5B
6A
6B
A
B
1A
1B
2A
2B
3A
3B
4A
4B
5A
5B
6A
6B
A
B
1A
1B
2A
2B
3A
3B
4A
4B
5A
5B
6A
6B
A
B
1A
1B
2A
2B
3A
3B
4A
4B
5A
5B
6A
6B
A
B
GROUP 1
GROUP 2
GROUP 3
GROUP 4
X-BUS
these units must be properly fused.
Controls:
An 8 segment DIP switch on the com-
ponent face of the circuit board is used to
set the Master unit’s IQ address. A 5 seg-
ment DIP switch on the
MRX-24T T-board sets
the slave unit board address. A jumper on
the face of the module disconnects battery
backup on master units.
Display:
Power LED shows presence of +12
VDC supply, DSPI LED shows reception of
digital information addressed to the unit.
Power Requirements:
+12 VDC.
Aux Port:
Three pins of an 8 pin mini-barrier
strip provide Aux Ground reference, Aux Out
su10 VDC at 20 mA, and Aux In is a
sensing input where +3 to +20 VDC = Digital
High. Aux In floats, and therefor must be tied
to ground to force the input off.
Crown Bus:
Five pins of an 8 pin mini-barrier
strip allow connection to a two-wire 20 mA
current loop for Crown Bus communication.
The Crown Bus is a serial data communica-
tion standard used between a system inter-
face and its loop components.
Slave Bus
: The slave bus is a parallel commu-
nications medium used between a master
MRX unit and up to 31 slaves. Required con-
nections include SB1-8, XB4, and SB Ground.
All connectors are on mini-barrier strips lo-
cated on the T-board.
Dimensions:
2.5 inches (6.35 cm) wide for 2-
space IQ-CAG mounting; 7 inches (17.78 cm)
high, and 12.125 inches (30.8 cm) behind
mounting surface.
Finish:
Smooth black powder coat.
Relays:
Contacts: 48 (24 pair).
Contact Form: DPST.
Maximum Switching Voltage: 100
VAC Peak.
Maximum Switching Current: 0.5
amperes.
Maximum Carry Current: 1 ampere.
Operation Time: 1 msec.
Release Time: 1 msec.
Mechanical Life Expectancy: 10 mil-
lion operations.
Guaranteed Excellence
@crown
Crown International, Inc.
PO Box 1000
Elkhart, IN 46515-1000
Ph. 800-342-6939/219-294-8200
Fax. 219-294-8301
Trademark Notice:
MRX-12,
™
MRX-24,
™
and
SMX-6
™
are trademarks,
and
Crown
®
and IQ System
®
are registered trade-
marks of Crown International Inc.
MRX-24/24S Block Diagram
