Filter
Top Products
05
Introduction 1
The TX91 has reverse supply polarity protection and will operate with a
wide range of supply voltages (11 to 44VDC). It has an input sensor
break-protection circuit that forces the output current to go upscale when
the thermocouple wire opens. It also is provided with a screw terminal,
where the output current can be measured without interrupting the
power loop. The TX91 does NOT provide isolation between its input and
the 4-20 mAoutput; therefore, an undergrounded thermocouple junction
is suggested to prevent possible ground loops.
Note that most thermocouple transmitters with 4-20 mAoutputs,
including the TX91, are proportional with respect to the thermocouple
input voltage. However, the relationship between temperature and
millivolt for all the thermocouple types is somewhat non-linear. This
leads to maximum error at approximately the midpoint of the range as
shown in Figure 1-4.