62
SCXF-SVX01B-EN
Table O-GI-2. RTM Sensor Resistance vs. Temperature
Temperature (F)
Resistance (ohms)
Temperature (F)
Resistance (ohms)
-40
346.1
71
11.60
-30
241.7
72
11.31
-20
170.1
73
11.03
-10
121.4
74
10.76
-5
103.0
75
10.50
0
87.56
76
10.25
5
74.65
77
10.00
10
63.8
78
9.76
15
54.66
79
6.53
20
46.94
80
9.30
25
40.40
85
8.25
30
34.85
90
7.33
35
30.18
100
5.82
40
26.22
105
5.21
45
22.85
110
4.66
50
19.96
120
3.76
55
17.47
130
3.05
60
15.33
140
2.50
65
13.49
150
2.05
66
13.15
160
1.69
67
12.82
170
1.40
68
12.50
180
1.17
69
12.19
190
0.985
70
11.89
200
0.830
Owner
General
Information
Table O-GI-4. RTM Resistance Value vs. System Operating Mode
Resistance
applied to RTM Mode
CV Units
VAV Units
input terminals (Ohms)
Fan Mode
System Mode
System Mode
2320
Auto
Off
Off
4870
Auto
Cool
7680
Auto
Auto
Auto
10,770
On
Off
13,320
On
Cool
16,130
On
Auto
19,480
Auto
Heat
27,930
On
Heat
Note: Mode boundaries are 1000 to 40,000 ohms. Other boundaries are equal to the midpoint between the
nominal mode resistance.
Table O-GI-3. RTM Setpoint Analog Inputs
Cooling or Heating Setpoint Input (F)
Cooling Setpoint Input (F)
(using RTM as zone temp. source)
(using RTM as supply air temp. source)
Resistance (ohms)
40
40
1084
45
45
992
50
50
899
55
55
796
60
60
695
65
65
597
70
70
500
75
75
403
80
80
305
NA
85
208
NA
90
111
minimum. This input will override all VOM
inputs, if the VOM option is on the unit.
Occupied/Unoccupied Contacts
To provide night setback control if a
remote panel
with night setback was not
ordered, install a field-supplied contact.
This binary input provides the building’s
occupied/unoccupied status to the RTM. It
can be initiated by a time clock, or a
building automation system control
output. The relay’s contacts must be rated
for 12 ma @ 24 VDC minimum. Refer to
the appropriate wiring diagrams
(attached to the unit control panel for the
proper connection terminals in the unit
control panel.
Emergency Stop Input
A binary input is provided on the RTM
board for installation of a field-supplied
normally closed (N.C.) switch to use
during emergency situations to shut
down all unit operations. When open, an
immediate shutdown occurs. An
emergency stop diagnostic enters the
human interface and the unit will require
a manual reset. Refer to the unit wiring
diagrams (attached to the unit control
panel for the proper connection
terminals. The switch must be rated for
12 ma @ 24 VDC minimum. This input
will override all VOM inputs, if the VOM
option is on the unit.
VAV Box Option
To interlock VAV box operation with
evaporator fan and heat/cool modes,
wire the VAV boxes/air valves to VAV box
control connections on the terminal block.
Supply Duct Static Pressure Control
The RTM relies on input from the duct
pressure transducer when a unit is
equipped with IGV or VFD to position the
IGV or set the supply fan speed to
maintain the supply duct static pressure
to within the static pressure setpoint
deadband.
RTM Sensors
RTM sensors include: zone sensors with
or without setpoint inputs and modes,
supply air sensor, duct static pressure,
outside air temperature, outside air
humidity, airflow proving, and dirty filter.
