User`s manual

2 cHAPTER 1: Introduction
Model 335 Temperature Controller
The Model 335 supports the industry’s most advanced line of cryogenic temperature
sensors as manufactured by Lake Shore, including diodes, resistance temperature
detectors (RTDs), and thermocouples. The controller’s zone tuning feature allows you
to measure and control temperatures seamlessly from 300 mK to over 1,500 K. This
feature automatically switches temperature sensor inputs when your temperature
range goes beyond the useable range of a given sensor. You’ll never again have to be
concerned with temperature sensor over or under errors and measurement

continuity issues.
The intuitive front panel layout and keypad logic, bright vacuum fluorescent display,
and LED indicators enhance the user-friendly front panel interface of the Model 335.
Four standard display modes are offered to accommodate different instrument con
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figurations and user preferences. Say goodbye to sticky notes and hand written labels,
as the ability to custom label sensor inputs eliminates the guesswork in remembering
or determining the location to which a sensor input is associated. These features,
combined with USB and IEEE-488 interfaces and intuitive menu structure and logic
supports efficiency and ease of use.
As a replacement to our popular Model 331 and 332 temperature controllers, the
Model 335 offers software emulation modes for literal drop-in compatibility. The
commands you are accustomed to sending to the Model 331 and 332 will either be
interpreted directly or translated to the most appropriate Model 335 setting. The
Model 335 comes standard-equipped with all of the functionality of the controllers it
replaces, but offers additional features that save you time and money. With the
Model
335, you get a temperature controller you control from the world leader in
cryogenic thermometry.
1.1.1 Sensor Inputs
The Model 335 offers two standard sensor inputs that are compatible with diode and
RTD temperature sensors. The field-installable Model 3060 option adds thermocou
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ple functionality to both inputs.
Sensor inputs feature a high-resolution 24-bit analog-to-digital converter and each
of the two powered outputs function as separate current sources. Both sensor inputs
are optically isolated from other circuits to reduce noise and to deliver repeatable
sensor measurements. Current reversal eliminates thermal electromagnetic field
(EMF) errors in resistance sensors. Ten excitation currents facilitate temperature
measurement and control down to 300 mK using appropriate negative temperature
coefficient (NTC) RTDs. Autorange mode automatically scales excitation current in
NTC RTDs to reduce self heating at low temperatures as sensor resistance changes by
many orders of magnitude. Temperatures down to 1.4 K can be measured and con
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trolled using silicon or GaAlAs diodes. Software selects the appropriate excitation cur-
rent and signal gain levels when the sensor type is entered via the instrument front
panel. To increase your productivity, the unique zone setting feature automatically
switches sensor inputs, enabling you to measure temperatures from 300 mK to over
1,500 K without interrupting your experiment.
The Model 335 includes standard temperature sensor response curves for silicon
diodes, platinum RTDs, ruthenium oxide RTDs, and thermocouples. Non-volatile
memory can also store up to 39 200-point CalCurves for Lake Shore calibrated tem
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perature sensors or user curves. A built-in SoftCal algorithm can be used to generate
curves for silicon diodes and platinum RTDs that can be stored as user curves. Tem
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perature sensor calibration data can be easily loaded into the Model 335 tempera-
ture controller and manipulated using the Lake Shore curve handler software
program.