Emerson MultiFlex RTU, Installation And Operation Manual

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14 • MultiFlex RTU Operator’s Guide 026-1706 Rev 3
4.2.2. MultiFlex RTU Auxiliary
Output Types
Output points #6 and #7 on the RTU board are
configurable in the RTU software. Table 4-4 lists
all of the possible output types that can be
chosen for these outputs.
4.2.3. Wiring Outputs to Points
The MultiFlex RTU has Form C relay contacts.
Figure 4-7 shows how to wire the three-terminal
Form C contact.
One wire of the two-wire connection should
always be connected to the middle terminal. The
second wire must either be connected to the N.C.
terminal (if you want the path to be closed when
the relay is de-energized) or the N.O. terminal (if
you want the path to be open during power
failure).
The contacts you choose also affect what the
board’s fail-safe dip switch will need to be set to
for proper operation. Refer to Table 4-5 and
Table 4-6 on page 15.
6 AUX1 Configurable in RTU
software (see Section
4.2.2.,
MultiFlex RTU
Auxiliary Output Types
).
7 AUX 2 Configurable in RTU
software (see Section
4.2.2.,
MultiFlex RTU
Auxiliary Output Types
).
8 ECON Two-position economizer,
or contactor for analog
economizer.
Auxiliary Output
Type
Description
COOL 3 Third stage of cool.
COOL 4 Fourth stage of cool.
HEAT 3 Third stage of heat.
HEAT 4 Fourth stage of heat.
FAN 2 Additional fan or 2nd fan speed.
HEAT PUMP REV
VALVE - CLOSED
(HEAT)
If a heat pump is being used, this
reversing valve output will close
when cooling stages are active and
open when heating stages are
active.
ALARM This relay will be activated when
any RTU alarm is generated, and
return to normal when the alarm
condition is acknowledged, reset, or
cleared from Einstein or BCU.
Table 4-4 - Auxiliary Output Types
RTU
Output
Point
Number
Label
Device to Connect To
This Point
Table 4-3 - RTU Default Outputs
HUMIDITY An output controlling a humidifier.
HEAT PUMP REV
VALVE - CLOSED
(COOL)
If a heat pump is being used, this
reversing valve output will close
when heating stages are active and
open when cooling stages are
active.
FAIL-SAFE Output relay will be ON when the
RTU is on-line with the Einstein or
BCU, and OFF when the RTU is
off-line.
ECON SHADOW Operates the same as the ECON
output (ON when economization is
OK, OFF when economization is
not OK).
DEHUM Output for controlling a
dehumidifying device.
Figure 4-7 - Form C Contact Wiring
Auxiliary Output
Type
Description
Table 4-4 - Auxiliary Output Types
N.C. N.O. N.C. N.O.
RELAY IS
CLOSED
ON POWER
FAILURE
RELAY IS
OPEN ON
POWER
FAILURE