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INSTALLATION AND CONTROLLER OPERATING
INSTRUCTIONS
Wiring and Electrical Connections
Before connecting cables make sure the power supply
complies with the rated voltage requirements. Separate
the probe cables from the power supply cables, the
outputs and the power connections. Do not exceed
the maximum current allowed on each relay (3A
resistive). In case of heavier loads use a suitable
external relay or contactor. Always use a Class 2
transformer with minimum power 5VA.
The power supply for the controller is 19-28VAC,
48-62Hz. The maximum load is 5 VA. 24V power to
the module must be on any time the unit is on and
should not be interrupted by any control. Center tap
transformers are not to be used.
Probes Connection
If using terminal ends be sure there are no bare parts
which could cause short circuiting or introduce noise
disturbance at high frequencies. To minimize the
induced disturbances use shielded cables with the
shield connected to earth.
Pressure probe (4 - 20 mA): respect the polarity.
Pb1 is suction; Pb2 is condenser.
Supply
24V
© 2013 Emerson Climate Technologies, Inc.
Printed in the U.S.A.
Application Engineering
B U L L E T I N
Figure 3 - TTL / RS485 Serial Converter
*
*
Pb1
Pb2
1
5 7
2 4 6 8 10
12V
40mA
Figure 4 - XC643 Module Connections
TTL/RS485 external converter: used to convert the
TTL output into a RS485 (+) and (-) signal for the
monitoring system MODBUS_RTU compatible.
(XWEB).
Note! When connecting to an E2 System controller for
supervisory control, the polarity from the XC643 should
be reversed from the polarity at the E2 communication
port. The XC643CX uses a 9600 baud rate.
Temperature probe (NTC 10K): Temperature probes
should be insulated from direct air streams to correctly
measure the temperature.
Probe Wiring
The XC643CX is capable of regulating the compressors
and condenser fans on any of the following types of
pressure/temperature sensors. The user must use the
same type of sensor to control the compressors and
the fans.
- 4-20mA pressure transducers (refer to Figure 4a)
- 0.5-4.5V ratiometric pressure transducers (refer
to Figure 4b)
- NTC 10K temperature sensors (refer to Figure 4c)
Note!
The 14-pin connector consists of low voltage
wires. Keep the cables away from the power cables.
Use shielded cable to lengthen the cables.
PIN 4 is the common line for the temperature probes PIN
6 gives a 12Vdc supply for the 4-20mA pressure
transducers
PIN 10 is the ground connection for ratiometric pressure
transducers
Digital Line O
Fan2
Fan1 Comp2 Comp
15 17 19
16 18 20
Hot Key/TTL
6
AE8-1386 R1
ut
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