TX91A-92A-Srs-Tx

Supported Applications

The Omega TX90A Series comprises miniature, low-cost temperature transmitters designed to convert thermocouple or RTD signals into a standardized output. These devices are engineered for installation in standard protection heads and serve as head-mount signal conditioners that accept Type J, K, T, E Thermocouples or 100 Ω Platinum (alpha = 0.00385) RTDs.

The series converts input signals to a 4 to 20 mA dc output referenced to the mV input of thermocouples or the resistance of 100 Ω Pt RTDs. The TX91A models function as non-linearized transmitters for thermocouple inputs, while linearization is available specifically for RTD applications via the -L suffix (e.g., TX92A--L).

Operating Conditions & Performance

The series delivers an accuracy of ±0.1% of Full Scale, which includes effects of linearity, hysteresis, and repeatability referenced to the mV input or resistance.

• Process Temperature: -40 to 85°C (-40 to 185°F)
• Storage Temperature: -46 to 121°C (-50 to 250°F)
• Power Supply: 8 to 50 Vdc (24V nominal), with upscale break protection
• Load Resistance: Vs - 8 / 0.020A

The transmitters are non-isolated and feature a compact form factor measuring 31.75 H x 44.5 mm D (1.25 x 1.75"), with height including the terminal strip.

Configuration Options

The TX90A Series supports multiple configuration options for sensor inputs, output linearization, and assembly styles to accommodate diverse installation requirements.

Sensor Inputs & Ranges

• Thermocouple (TX91A): Accepts Type J, K, T, or E. Available ranges include -40 to 60 °C (-40 to 140 °F) through 0 to 500 °C (32 to 932 °F), with specific range codes such as J2 for -18 to 93 °C (0 to 200 °F).
• RTD (TX92A): Accepts 100 Ω Platinum, alpha = 0.00385. Ranges mirror thermocouple options from -40 to 60 °C (-40 to 140 °F) up to 0 to 500 °C (32 to 932 °F).
• Linearization: The -L suffix designates RTD transmitters with output linearized to temperature. Note that standard RTDs are slightly non-linear, diverging from actual temperature by approximately 1% at the mid-point of full scale.

Housings & Assemblies

The transmitter body is mountable in any standard protection head. Complete assemblies are available with specific wetted materials and dimensions:

• Cast Iron Head (NB1TXA): Includes a 12" L, ¼ OD probe with an ungrounded junction and 304 SS sheath.
• Aluminum Head (NBSTXA): Features the same 12" L, ¼ OD, 304 SS sheath configuration as the cast iron variant but in an aluminum housing.
• RTD Assemblies (PRTXA): TX92A transmitters mounted in a cast iron head with a 12" L, ¼ OD, ungrounded junction RTD probe. Lengths can be customized by adding the suffix -XX for inches.
• Housing Materials: Cast iron or aluminum options are available depending on the assembly model selected.

Power & Accessories

The series supports regulated power supplies including PSR-24S (screw terminal), PSR-24L (UL, stripped leads), and PSR-24L-230 (stripped leads, 230 Vac input). Mounting accessories include the RT mounting track (1.2 m / 48") and TX90-BR bracket.

Key Product Differences

The primary distinction within the series lies between thermocouple and RTD inputs, as well as linearization requirements:

• TX91A Models: Designed for Type J, K, T, E Thermocouples. Output is non-linearized.
• TX92A Models (Standard): Designed for 100 Ω Pt RTDs with alpha = 0.00385. Output is non-linearized resistance-to-current conversion.
• TX92A-L Models: Identical to standard TX92A but includes linearization of the output signal to temperature.

Housing variations differentiate between cast iron (NB1TXA, PRTXA) and aluminum (NBSTXA) protection heads. Custom scaling (-FS) is available for an additional charge upon contacting engineering.