Analog inputs for heat pump applications
CNT-SVX12C-EN
53
AI2: Outdoor air temperature or generic temperature
The AI2 analog input can function as either:
•
An outdoor air temperature input
•
A generic temperature input
If AI2 is configured as the local (hard-wired) outdoor air temperature
input, the controller receives the temperature as a resistance signal from
a 10 k
Ω
thermistor wired to analog input AI2. An outdoor air tempera-
ture value communicated by means of a LonTalk link can also be used for
controllers operating on a BAS. If both hard-wired and communicated
outdoor air temperature values are present, the controller uses the com-
municated value.
If you set DIP switch 3 to
ON
for economizing (see “DIP switch settings”
on page 48), you automatically configure AI2 as an outdoor air tempera-
ture input. Economizing (
free cooling
) is a function whereby outdoor air is
used as a source of cooling before hydronic or DX cooling is used. The
Tracer ZN517 uses the outdoor air temperature value to determine
whether economizing is feasible. Economizing is not possible without a
valid outdoor air temperature. (For more information, see “Economizing”
on page 60.)
If AI2 is configured as a generic temperature input, it can be monitored
by a BAS. The controller receives the temperature as a resistance signal
from a 10 k
Ω
thermistor wired to analog input AI2. The generic tempera-
ture input can be used with any Trane 10 k
Ω
thermistor. The thermistor
can be placed in any location and has no effect on the operation of the con-
troller. If you set DIP switch 3 to
OFF
(see “DIP switch settings” on
page 48), you automatically configure AI2 as a generic temperature input.
DAT: Discharge air temperature
The DAT analog input functions as the local discharge air temperature
input. The controller receives the temperature as a resistance signal from
a 10 k
Ω
thermistor wired to analog input DAT. The thermistor is typically
located downstream from all unit heating and cooling coils at the unit dis-
charge area.
Trane recommends the use of a discharge air temperature sensor to uti-
lize the cascade control function (see “Cascade zone control” on page 56).
Cascade control is a more accurate method of temperature control. If no
discharge air temperature sensor is used, the controller will default to
control based solely on the zone temperature (see “Simplified zone con-
trol” on page 56).
Note:
AI2 is not polarity sensitive; you can connect either terminal to
either sensor lead.
Note:
DAT is not polarity sensitive; you can connect either terminal
to either sensor lead.
Содержание Tracer ZN517
Страница 1: ...CNT SVX12C EN Installation and Operation Tracer ZN517 Unitary Controller...
Страница 2: ......
Страница 3: ...Installation and Operation Tracer ZN517 Unitary Controller CNT SVX12C EN April 2005...
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Страница 12: ...Table of contents vi CNT SVX12C EN...
Страница 38: ...Chapter 4 Sequence of operations for the 2 heat 2 cool configuration 26 CNT SVX12C EN...
Страница 56: ...Chapter 6 Sequence of operations for the 4 cool configuration 44 CNT SVX12C EN...
Страница 92: ...Chapter 10 Status indicators for operation and communication 80 CNT SVX12C EN...
Страница 104: ...Chapter 12 Troubleshooting 92 CNT SVX12C EN...
Страница 110: ...Index 98 CNT SVX12C EN...