Omega TX91 manual Introduction

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Introduction

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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 mA output; therefore, an undergrounded thermocouple junction is suggested to prevent possible ground loops.

Note that most thermocouple transmitters with 4-20 mA outputs, 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

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shown in Figure 1-4.

 

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Contents User’sGuide Servicing North America Return Requests / Inquiries Introduction Calibration Instructions Introduction General DescriptionIntroduction TX91 Thermocouple Transmitter Introduction Introduction Straight line Approximation of Curve Features Models AvailableTX91 Models Available Model Number Description Unpacking Installation Mounting the TX91Assembly of the TX91 Transmitter Inside RT Mounting Track in inches TX90-BR Mounting Bracket in inches Mounting Track RT Bracket TX90-BR Wiring the TX91 Refer to Figure Wiring Diagram for the TX91 Potentiometers Calibration Instructions Equipment RequiredSet-up of Equipment Calibration Procedures Refer to Figure Calibration Instructions Calibration Set-Up Calibration Set-Up. Alternate Calibration Values for the TX92 Troubleshooting Guide Current rating on the power supplyTroubleshooting Guide Accessories Model No DescriptionSpecifications GeneralInput Intrinsically Safe Interconnection Diagram WARRANTY/DISCLAIMER Shop online at omega.com
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