Dataq DI-720-EN, User Manual

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DI–720/DI–722/DI–730 Series User Manual
Accessories
62
DI-8B34 Linearized 2- or 3-Wire RTD Input Modules
Each DI-8B34 module isolates, filters, amplifies, and linearizes a single channel of temperature input from an RTD
and provides an analog voltage output.
RTD excitation is provided from the module using two matched current sources. When using a 3-wire connection,
this method allows equal currents to flow through the sensor leads, cancelling the effects of lead resistances. The
excitation currents are small (0.25mA) which minimizes the self-heating of the RTD.
Signal filtering is accomplished with a three-pole filter optimized for time and frequency response which provides
70dB of normal-mode-rejection at 60Hz. One pole of this filter is on the field side of the isolation barrier for anti-
aliasing, and the other two are on the system side.
A special input circuit on the DI-8B34 module provides protection against accidental connection of power-line volt-
ages up to 240VAC. Clamp circuits on the I/O and power terminals protect against harmful transients.
Ordering Information
MODEL INPUT RANGE OUTPUT RANGE ACCURACY*
DI-8B34-01 -100°C to +100°C (-148°F to +212°F) 0V to +5V ±0.20°C
DI-8B34-02 0°C to +100°C (+32°F to +212°F) 0V to +5V ±0.15°C
DI-8B34-03 0°C to +200°C (+32°F to +392°F) 0V to +5V ±0.20°C
DI-8B34-04 0°C to +600°C (+32°F to +1112°F) 0V to +5V ±0.45°C
* Includes conformity, hysteresis and repeatability.