BAPI LM334 Catalog Page
LM334 Room/Setpoint/Override/Comm Jack
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Sensor T ermination and Tr oubleshooting
9615_ins_LM334_Room_Set_OR_CJ Printed Februar
General Information
Building Automation Products, Inc.’s (BAPI) room sensors are designed and manufactured to install easily and
function long-term under real-world conditions. Units incorporate double-sided circuit boards and through-hole
soldering for all moving components to ensure durable electrical and mechanical connections. Semiconductors
ARE polarity sensitive and can be used in two (2) wire or three (3) wire configurations. Advantages of 2 wire
current sensors include cost saving of having to run only 2 wires to each sensor and a lower susceptibility to electrical
noise than 3 wire voltage sensors. It is recommended that the power be turned off before connecting the
sensors to the system. BAPI recommends that wiring for these units not be run in the same conduit as line voltage
wiring or with wiring used to supply inductive loads such as motors, generators, and coils. See the Termination
section for a diagram of the general layout of the circuit board contained within the unit. Some components shown
may not be present, depending on the exact configuration ordered.
Termination
LM334-10K Room Sensor
WARNING:
DO NOT wire sensor with power applied
(In a situation when the controller power must be present,
terminate the sensor before the controller, or connect
the controller minus the +Vdc, then the sensor wires,
and then connect the +Vdc wire last.)
1. For LM334 units, sensor is measured at TB2 Sen. For
LM334-10K units, a 10K ohm 0.1% resistor must be
installed between the controller and ground & the sensor
is measured at TB2 Gnd.
2. Overide (O/R) and Setpoint (Set) are with reference to
TB2 Gnd.
TERMINAL CONNECTIONS
V+ = +5 to 30 VDC input
Sen = Sensor out, (LM334-10K only)
O/R = Overide
Set = Setpoint output, 2.89 to 3.17 volts
Gnd = Common for O/R and Set
TB1 = Comm jack power (+5 Volts)
TB2 = Comm +
TB3 = Comm TB4 = Comm Jack Ground
Jumper configurations (both units)
J1: Selects LM334 sensor
J2: Overide//setpoint
5 to 30VDC
5 to 30VDC
TB1
1
+V
J1
Sensor
Output
(10mV/°K)
Sen
LM334 Room Sensor
TB1
1
J1
+V
Sen
4
O/R
Set
Gnd
(Overide)
(Setpoint)
4
O/R
Gnd
Set
TB2
J2
TB2
J2
Ground
26, 2001
Ground
Sensor output
(1uA/°K)
10K ohm 0.1%
resistor
J2: Overide as seperate input
J2: Overide // sensor
(Overide)
(Setpoint)
LM334 Room/Setpoint/Override/Comm Jack
Sensor T ermination and Troubleshooting
9615_ins_LM334_Room_Set_OR_CJ
Offsetting
All LM334 sensors will have the following information provided on a label:
Printed February 26, 2001
Thermistor Reading_______
The actual temperature reading
according to a thermometer that is
certified traceable to recognized
standards by the National Institute of
Sensor Reading ______
The temperature reading according to
the LM334 sensor , using the output in
either mA or mV and converting the
output to a Fahrenheit temperature.
Offset_______
The difference between the
Thermometer Reading and the
Sensor Reading.
Standards and Technology (NIST).
To correct the Sensor Reading, simply add the offset value to the sensor reading so that it equals the thermometer
reading.
e.g. Therm Reading 74.6 Sensor Reading 73.0 Offset +1.6
Correction: Add (+1.6) °F to the sensor for an accurate reading: 73 + 1.6 = 74.6°F
e.g. Therm Reading 75.4 Sensor Reading 77.2 Offset -1.8
Correction: Add (-1.6) °F to the sensor for an accurate reading: 77.2 + (-1.8) = 75.4°F
Trouble Shooting
If the unit you installed does not respond properly , please
go through the following steps:
1. Set your meter to the mV setting.
2. Measure the voltage between the “Sen” and “GND.”
See diagrams above in the Termination section.
3. Compare the voltage reading to the voltage listed in
the output table.
4. If the sensor reads significantly lower or 0, then your
sensor is shorted.
5. If the sensor reads significantly higher or OL
(overload) then the sensor is open.
6. If the sensor reads properly, verify that the controller
is operating correctly.
Temp. LM334
°F °C (mA) (V )
50 10 283.2 2.83
60 15 .56 288.7 2.8 9
62 16 .67 289.8 2.9 0
64 17 .78 290.9 4 2.91
66 18 .89 292.1 2.9 2
68 20 293.2 2.93
70 21 .11 294.3 2.9 4
72 22 .22 295.4 2.9 5
74 23 .33 296.5 2.9 7
76 24 .44 297.6 2.9 8
77 25 298.2 2.98
78 25 .56 298.7 2.9 9
80 26 .67 299.8 3.0 0
82 27 .78 300.9 3.0 1
84 28 .89 302.1 3.0 2
86 30 303.2 3.03
88 31 .11 304.3 3.0 4
90 32 .22 305.4 3.0 5
100 37.78 31 0.9 3.1 0
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