Carrier 38APD130 - Configuring 4 to 20 Ma Temperature Reset

133
4-20 mA Temperature Reset
— The energy management
module (EMM) must be used for temperature reset using a 4 to
20 mA signal. The signal can be monitored to the control at
the scrolling marquee point 4-20 mA Reset Signal (Inputs
o
4-20
o
RSET).
To use 4-20 mA temperature reset, two variables must be
configured. In Configuration
o
RSET, set these items:
• Cooling Reset Type (CRST): Configure for the type of
reset desired, 4-20 mA Input
• MA.DG: Set to the amount of reset desired with a 20 mA
signal. The control will interpolate between 0 degrees reset
at 4 mA and the value entered for MA.DG at 20 mA.
The 4-20 mA input temperature reset example shown in Ta-
ble 61 and Fig. 153 and 154 provides 0° F (0° C) reset to the
Active Set Point (Run Status
o
VIEW
o
SETP) if RSET =4
mA and 6° F (3.3° C) reset if RSET=20 mA. Using these val-
ues, if SETP=55 F (12.8 C) and RSET =4 mA, the Control
Point (Run Status
o
VIEW
o
CTPT) will reflect 0° F (0.0° C)
reset or 55 F (12.8 C). If RSET=20 mA, the Control Point
(Run Status
o
VIEW
o
CTPT) will reflect 6° F (3.3° C) reset
or 61 F (16.1 C). Between RSET =4 mA and RSET=20 mA a
proportional reset amount will be applied to CTPT.
Table 61 — Configuring 4 to 20 mA Temperature Reset
*Not supported.
CAUTION
To avoid unit damage, care should be taken when interfac-
ing with other manufacturer’s control systems due to
power supply differences, full wave bridge versus half
wave rectification. The two different power supplies cannot
be mixed. ComfortLink controls use half wave rectifica-
tion. A signal isolation device should be utilized if a full
wave bridge signal generating device is used.
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
MODE
o
SUB-MODE: CONFIGURATION
o
RSET
CRST Cooling Reset Type
0=No Reset (Default)
1=4-20 Input
2=Out Air Temp
3=Return*
4=Space Temp
1
MA.DG 4-20 – 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)