Trane Tracer ZN521, Инструкция по установке и эксплуатации

Страница: 14 / 60

14 CNT-SVX07D-EN
Input/output functions and wiring for typical applications
Each function is explained in the following paragraphs. For an explanation of the diagnostics
generated by each binary input, see
“Diagnostics,” p. 48 . For more information about how the
controller operates, see “Sequence of operations,” p. 31
BI1: Low-coil-temperature detection
Note: BI1 applies to hydronic/steam coils only.
The function of low-coil-temperature detection is to protect the coil from freezing. If BI1 is wired
to a binary low-coil-temperature detection device (freeze-protection switch) and a low-coil-
temperature condition exists, the Tracer ZN521 will detect the condition and generate a Low Coil
Temp Detection diagnostic.
BI2: Condensate overflow
The function of condensate overflow is to prevent the condensate drain pan from overflowing and
causing water damage to the building. If BI2 is wired to a condensate overflow switch and the level
of condensate reaches the trip point, the Tracer ZN521 will detect the condition and generate a
Condensate Overflow diagnostic.
BI3: Occupancy or generic binary input
The BI3 binary input can function as either:
• The occupancy input
• A generic binary input
The function of occupancy is to save energy by spreading zone setpoints when the zone is
unoccupied. As the occupancy input, BI3 can be used for two related functions. For stand-alone
controllers, BI3 can be hard-wired to a binary switch or timeclock to determine the occupancy
mode—either occupied or unoccupied. For controllers receiving a BAS-communicated occupancy
request, the function of BI3 is to change the mode from occupied to occupied standby. (For more
information on occupancy-related functions, see
“Occupancy modes,” p. 31 .)
BI3 is the only binary input that can be configured as generic. If configured as a generic binary input,
it can be monitored by a BAS and has no direct effect on Tracer ZN521 operation.
BI4: Fan status
The fan status input provides feedback to the controller regarding the fan’s operating status. If BI4
is wired to a fan status switch and the input indicates that the fan is not operating when the
controller has the fan controlled to on, the controller will generate a Low AirFlow—Fan Failure
diagnostic. (For more information, see
“Fan status,” p. 41 .)
Analog inputs
The Tracer ZN521 controller includes seven analog inputs. Table 4 describes their functions. Each
function is explained in the following paragraphs. For an explanation of the diagnostics generated
BI3
Occupancy or generic binary input
BI4
Fan status
Table 3. Binary inputs (continued)
Binary input
terminal label Function