Temperature Sensor Testing
Temperature Sensor Testing
The following sensor voltage and resistance table is provided to
aid in checking sensors that appear to be operating incorrectly.
Many system operating problems can be traced to incorrect sen-
sor wiring. Be sure all sensors are wired per the wiring diagrams
in this manual.
If the sensors still do not appear to be operating or reading cor-
rectly, check voltage and/or resistance to confi rm that the sensor
is operating correctly per the table. Please follow the notes and
instructions in
Figure 19, below
when checking sensors.
Figure 19: Testing Resistance On E-BUS Digital Room Sensors
MADE IN USA
YS102370 R1
ModBus LCD Space Sensor
W
attMaster Controls, Inc
PROGRAM
COMM
LED1
EXTERN
THERM
+12Vdc
GND
-COM
+COMM
SHLD
P1
R1
F3
U4
C18
R36
C30
D1
L1
C17
R38
R37
C19
C31
C21
TB1
X2
J3
C3
C24
C23
C1
C8
C12
C13
C14
C16
C25
C26
J2
Q2
R3
R4
R6
R8
R9
R10
R1
1
R12
R14
R13
R15
TH1
U3
X1
C27
R18
C20
D4
R17
D6
D7
R32
R33
D5
1
J1
DISP1
C15
D2
R2
R5
R7
R16
R19
R20
U6
U2
TB2
R35
2.2
uF
R18
1002
1001
1330
4751
4751
1001
1001
.1uF
9.2
1M
hz
4751
4751
LTC
35
02
.1uF
15pF
6.8uF
.1uF
10uF
3162
1502
6.8uH
1002
24F
C1025
6.8uF
6.8uF
1001
4751
.1uF
.1u
F
1000
1002
4751
.1uF
4751
A
D
M3
483
.1uF
.1uF
RS1G
X05
MICR
OC
HIP
PIC3
2M
X44
0F
512H-80
IP
T
.1u
F
10RO
10RO
470pF
X05
+
+
-
-
T
E-BUS Digital Room Sensor
Back View
Note:
,
For This Test The Sensor Must Be
Disconnected From Its E-BUS Cable As
Shown Or Disconnected From the VAV/Zone
Controller If Wired To The Board. The Meter
Must Be Set To Measure Resistance in
Ohms. Use The Table On The Facing Page
To Determine If The Sensor Is Reading The
Correct Resistance Value For The Ambient
Temperature. This Resistance Value Should
Match The Temperature Value Listed Next To
The Resistance Value In The Table. The
Temperature Should Be Measured With A
Separate Accurate Temperature Measuring
Device Located In The Area Where The
Sensor Is Currently Located.
Test Points Labeled
“Extern Therm” On
Sensor Circuit Board
E-BUS Cable
Disconnected
From Sensor Port
9302
41
VAV/Zone Controller Package
TROUBLESHOOTING
