129
C.TYP=
9
(VAV Setpoint). This feature is not available for
Machine Control Types
C.TYP=
4
(2 Stg Tstat),
C.TYP=
7
(Pct
Cap) and
C.TYP=
8
(Dual Tstat).
If the unit is in a cooling mode and configured for ramp
loading, the control makes 2 comparisons before deciding to
change stages of capacity. The control calculates a temperature
difference between the control point and supply temperature. If
the difference is greater than 4° F (2.2° C) and the rate of
change (°F or °C per minute) is more than the configured Cool-
ing Ramp Loading value (
Configuration
o
SLCT
o
CRMP
) at
the current capacity stage, the control does not allow any
change to the current stage of capacity.
If Ramp Loading is active, the control will indicate Operat-
ing Mode, Ramp Load Limited (
Operating Modes
o
MODE
o
MD05
will indicate YES). See Table 58.
Table 58 — Configuring Ramp Loading Control
TEMPERATURE RESET — The control system is capable
of changing the controlling set point based on several different
methods: space temperature (SPT), outside air temperature
(OAT), and from an externally powered 4 to 20 mA signal.
The set point can be adjusted up or down depending on how it
is configured.
If Temperature Reset is active, the control will indicate Op-
erating Mode, Temperature Reset (
Operating Modes
o
MODE
o
MD14
will indicate YES).
NOTE: Temperature Reset is available for a Control Type
(
Configuration
o
OPT2
o
C.TYP
) that uses a Supply Air
Temperature set point, such as
C.TYP=
1
(VAV),
C.TYP=
3
(TSTAT MULTI) or
C.TYP=
5
(SPT MULTI). While Temper-
ature Reset will operate with
C.TYP=
9
(VAV Setpoint), since
the set point temperature is being supplied to the control, Tem-
perature Reset should be accomplished by the building man-
agement system incorporating any required reset in the set
point signal.
Space Temperature Reset — Space temperature must be
available to the unit controls, either by communication via a
network connection or by a wired sensor. Any one of the
accessory space temperature sensors (T55, T56, or T59) can be
installed for space temperature reset.
To use space temperature reset, four variables must be con-
figured. In
Configuration
o
RSET
, set these items:
• Cooling Reset Type (
CRST
): Configure for the type of
reset desired, Space Temperature
• Remote – No Reset Temp (
RM.NO
): Set to the tempera-
ture that no reset should occur
• Remote – Full Reset Temp (
RM.F
): Set to the tempera-
ture that maximum reset is to occur
• Remote – Degrees Reset (
RM.DG
): Set to the maximum
amount of reset desired
The space temperature reset example shown in Table 59 and
Fig. 149 and 150 provides 0° F (0° C) reset to the Active Set
Point (
Run Status
o
VIEW
o
SETP
) if Space Temperature
(
Temperatures
o
UNIT
o
SPT
) =72 F (22.2 C), and 6 F (3.3 C)
reset if
SPT
=68 F (20.0 C). Using these values, if
SETP
=55 F
(12.8 C) and SPT=68 F (20.0 C) or less, the Control Point
(
Run Status
o
VIEW
o
CTPT
) will reflect 6 F (3.3 C) reset or
61 F (16.1 C). If
SPT
=72 F (22.2 C) or more, the Control Point
(
Run Status
o
VIEW
o
CTPT
) will reflect 0° F (0.0° C) reset
or 55 F (12.8 C). Between
SPT
=68 F (20.0 C) and
SPT
=72 F
(22.2 C) a proportional reset amount will be applied to
CTPT
.
Table 59 — Configuring Space Temperature Reset
*Not supported.
CONFIGURATION
o
OPT2
ITEM
EXPANSION
COMMENTS
C.TYP
Machine Control Type
Range: 1 to 9
1 (VAV)
3 (Tstat Multi)
4 (Tstat 2stg)
5 (SPT Multi)
7 (PCT Cap)
8 (Dual Tstat)
9 (VAV Setpoint)
Default: 4
Value must be set to 1, 3, 5
or 9
CONFIGURATION
o
SLCT
RL.S
Ramp Loading Select
Range: DSBL/ENBL
Default: ENBL
Set to ENBL to activate
CRMP
Cooling Ramp
Loading
Range: 0.2 to 2.0
Default: 1.0
CONFIGURATION
o
OPT2
ITEM
EXPANSION
COMMENTS
EXAMPLE VALUE
C.TYP
Machine Control Type
Range: 1 to 9
1 (VAV)
3 (Tstat Multi)
4 (Tstat 2stg)
5 (SPT Multi)
7 (PCT Cap)
8 (Dual Tstat)
9 (VAV Setpoint)
Default: 4
Value must be set to 1, 3, 5 or 9
1, 3, 5 or 9
CONFIGURATION
o
RSET
CRST
Cooling Reset Type
0=No Reset (Default)
1=4-20 Input
2=Out Air Temp
3=Return*
4=Space Temp
4
RM.NO
Remote – No Reset Temp
Range: 0.0 to 125.0 F
(–17.8 to 51.7 C)
Default: 125.0 °F (51.7 C)
72.0 F (22.2 C)
RM.F
Remote – Full Reset Temp
Range: 0.0 to 125.0 F
(–17.8 to 51.7 C)
Default: 0.0 F (–17.8 C)
68.0 F (20.0 C)
RM.DG
Remote – Degrees Reset
Range: –30.0 to 30.0
'
F
(–16.7 to 16.7
'
C)
Default: 0.0
'
F (0.0
'
C)
6.0
'
F
(3.3
'
C)
