Wavelength Electronics LFI-3751, Руководство пользователя

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Chapter 2 - Front Panel Operation
Controlling Temperature with an LM335
Controlling Temperature with an LM335
1. Wiring an LM335
Wire the LM335 to the Output Connector on the rear panel. Shielded
cables are available (Wavelength part number CAT-220). Do not exceed
1 meter cable length. Refer to
Sensor Error Condition on page 55 if you
can’t clear a Sensor Error.
to pin 4
to pin 5
TO-92
(plastic package)
1
9
4
5
LM335
TO-46
(metal can package)
+
-
Bottom View
+
-
Bottom
View
P ACT T
LIM I
AUX T
TE V
SET T
TE I
B
C
I
A
D
48
Default LM335 Confi guration
= 3.000
= 3.000
= 10.00 mV / K
= 0.0 mV
A
B
C Slope
Offset
[A1]
[A2]
[B1]
[C1]
Key to accurately measuring and controlling temperature with an LM335 is
properly entering the confi guration data. An LM335 produces a voltage
that changes linearly with temperature. To indicate to the LFI-3751 that
the sensor is an LM335,
A = (3.000, 3.000). To characterize the linear
response, the LFI-3751 requires a Slope and Offset . For the LM335,
B = Slope and C = Offset . With this information, the LFI-3751 can calculate
temperature from LM335 voltage and properly calculate the setpoint voltage
from the setpoint temperature.
2. Temperature vs. LM335 Voltage
The LM335 produces a voltage that changes linearly with temperature in
Kelvin. The LFI-3751 requires a
Slope and Offset to model this response
mathematically. To indicate you’re using an LM335, A = (3.000, 3.000). To
confi gure the response, B = Slope and C = Offset .
Enter A : (3.000, 3.000), B : Slope , and C : Offset through the front panel or
[A1], [A2], [B1], and [C1] via the RS-232 interface.
T = LM335 Temperature (°C)
V
LM335
= Voltage across pins 4 & 5
m
LM335
= LM335 Slope =
10 mV / Kelvin
b
LM335
= LM335 Offset = 0 mV
LM335 Temperature
V
LM335
- b
LM335
m
LM335
T = - 273.15