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| DI-5B35 Linearized
4-Wire RTD Input Modules |
Product Highlights
In RTD temperature measurement applications requiring
a very high level of accuracy, the DI-5B35 4-wire RTD
input module offers a significant advantage over 3-wire
measurement techniques. The DI-5B35 measures only the
voltage dropped across the RTD and almost completely ignores
the resistance or length of the RTD lead wires. The DI-5B34
3-wire RTD module provides lead resistance compensation,
but requires equal lead resistances, while the DI-5B35
does not require matched lead resistances.
Each DI-5B35 module provides a single channel of RTD input
which is filtered, isolated, amplified, linearized, and
converted to a high level analog voltage output. This
voltage output is logic switch controlled, which allows
these modules to share a common analog bus without the
requirement of external multiplexers.
The DI-5B35 module is designed with a completely isolated
computer side circuit which can be floated to ±50V
from power common (pin 16). This complete isolation means
that no connection is required between I/O common and
power common for proper operation of the output switch.
RTD excitation is provided from the module by a precision
current source. The excitation current is available on
two leads which are separate from the two input signal
measuring leads. The excitation current does not flow
in the input signal leads, which allows RTD measurements
to be totally independent of lead resistance. The excitation
current is very small (0.25mA for 100O Platinum and 120O
Nickel, and 1.0mA for 10O Copper) which minimizes self-heating
of the RTD.
Signal filtering is accomplished with a six-pole filter
which provides 95dB of normal-mode rejection at 60Hz and
90dB at 50Hz. Two poles of this filter are on the field
side of the isolation barrier, and the other four are
on the computer side. After the initial field-side filtering,
the input signal is chopped by a proprietary chopper circuit.
Isolation is provided by transformer coupling, again using
a proprietary technique to suppress transmission of common
mode spikes or surges. The module is powered from +5VDC,
±5%.
A special input circuit on the DI-5B35 provides protection
against accidental connection of power-line voltages up
to 240VAC.
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Models & Prices
| Part
Number |
Description |
Price |
Buy
Online |
| DI-5B35-01 |
100mV full scale input range |
£205 |
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| DI-5B35-02 |
1V full scale input range |
£205 |
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| DI-5B35-03 |
10V full scale input range |
£205 |
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| DI-5B35-04 |
150V full scale input range |
£205 |
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| DI-5B35C-01 |
0°C to +120°C (32°F
to +248°F) (10O at 0°C)e |
£205 |
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| DI-5B35C-02 |
0°C to 120°C (32°F to
+248°F) (10O at 25°C) |
£205 |
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| DI-5B35C-03 |
0°C to 160°C (32°F to
320°F) (10O at 0°C) |
£205 |
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| DI-5B35N-01 |
0°C to +300°C (32°F to
+572°F) |
£205 |
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