IET Labs PRS-370 SERIES, Operation Manual, Page: 13 / 54

INTRODUCTION
PRS-370 Series
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accuracy, good stability, and low zero resistance.
The PRS-370 is suited for automatic and
manual calibration and testing, simulation
of RTD’s, programmable loads, and many
other laboratory and industrial applications.
The PRS Series may be rack mounted to serve as
components in measurement and control systems.
The PRS-370 (Figure 1.1) is part of the
PRS family of high precision manual and
programmable decade substituters. This
series offers a wide choice of ranges, power,
voltage, and accuracies for a wide variety
of design and production applications.
The PRS-370 uses a microcontroller design to
enhance the ease of use and calibration. It provides
direct resistance substitution as well as RTD
(Resistance Temperature Detector) simulation. It
allows for higher precision and tight tolerances.
The PRS-370 is a precision resistance source
with excellent characteristics of accuracy,
stability, temperature coef
fi cient, and power
coef fi cient. It is direct reading without
the need to subtract “zero resistance.”
The PRS-370 offers the option of true
4-wire Kelvin measurement for calibration
applications and 2-wire mode for use
in series as a substitute resistor and for
RTD applications. The front panel display
indicates the mode selected: 2-wire or 4-wire.
There are 4 pre-programmed RTD
resistance tables, and others may be added
by the user. The controller allows for
other convenient programmed features.
The unique design makes adjustment of the
PRS-370 for calibration semiautomatic. An
internal calibration routine guides the user to
perform measurements using only a precision
ohmmeter and enter the measured values into
the PRS-370. No other standards are required.