Endress+Hauser TTR31 Thermophant T Temperature Switch

Endress+Hauser TTR31 Thermophant T temperature switch

The Endress+Hauser TTR31 is a Thermophant T temperature switch: a compact Pt100 thermometer with switching electronics and a display built into one device. It monitors process temperature and gives a PNP switch signal when a limit is exceeded, with the option of a second switch output or an active 4 to 20 mA output for temperature. This lets one device replace a probe, a controller and a trip amplifier on pumps, heat exchangers and cooling circuits. Seven Star LLC supplies the TTR31 in Oman and the GCC as an independent supplier in Muscat.

The technical information also covers the hygienic TTR35; this page covers the TTR31 with threaded or coupling process connection.

TTR31 technical specifications

How the TTR31 senses and switches

The sensor is a long-term stable platinum Pt100 in class A according to IEC 60751 with a sensor current of 0.6 mA or less. The integrated electronics compare the temperature with the set points and drive the outputs. Long-term drift is below 0.1 K per year, and the accuracy is below 0.5 K from −50 to +75 °C and below 0.65 K from 75 to 150 °C. The device is DESINA-compliant, an interface standard for machine-tool and automation connectors.

TTR31 electrical data and outputs

Supply is 12 to 30 V DC. Output versions are one PNP switch output, two PNP outputs, or one PNP output plus an active 4 to 20 mA output. The analogue alarm is 3.6 mA or below, or 21 mA or above, and the switch outputs go to a safe state (switch open) on a fault. LEDs and a digital display give function control and information on site. The operating temperature range is −50 to +150 °C. Connections include ISO threads, NPT 1/4 inch and NPT 1/2 inch, and compression or clamp options.

Choosing the TTR31 configuration

Define the switching logic (window or hysteresis, normally open or closed), the number of outputs and whether a temperature value is needed on 4 to 20 mA. Then choose immersion length, process connection and the output connector. If a thermowell is required because the line must stay closed during sensor change, use a modular thermometer with a separate switch amplifier instead.

Installing and setting the TTR31

Mount the device so that the sensor tip is in the flow, with enough immersion for good accuracy, and shield the housing from direct sun and radiant heat. Set the switch points on the display, test the switching with a dry-block calibrator or a hot-water bath, and note the settings. For safety-related trips, treat the TTR31 as a monitoring device and use certified safety instrumentation where required.

TTR31 applications in Oman and the GCC

Practical uses include cooling-water temperature trips on engines and compressors, bearing-oil monitoring on pumps, hot-water supply protection, process heater over-temperature alarms and package-unit protection. The wide ambient capability and the local display suit unmanned remote pumping stations in desert sites.

TTR31 compared with the TMR31

Information to send with a TTR31 RFQ

• Temperature range and switch points
• Number and type of outputs
• Thread or coupling, immersion length
• Supply voltage and connector
• Quantity and delivery location

Verification, maintenance and fault finding for the TTR31

Check the switching function at commissioning and after any maintenance by raising the temperature in a dry-block or a controlled hot-water bath and watching the display and the output state. Compare the displayed value with a reference thermometer; because the device is a thermometer with electronics, a difference between the display and the reference usually means a poor thermal contact or a stratified fluid rather than a failed sensor.

If an output does not switch, check the supply voltage at the device, the polarity, the load on the PNP output and the configured switching logic. The analogue alarm values of 3.6 mA or below and 21 mA or above indicate an internal fault or a sensor break, and the switch outputs open to the safe state in the same case. Keep the configured set points on a record sheet, because a replacement unit must be set up again with the same values. In dusty or oily sites wipe the display window, and avoid pressure washing directly at the connector unless the protection rating allows it.

Plan one spare per critical measuring point, with the same thread and immersion length, because the device is installed directly in the process and a replacement may require draining the line.

Site conditions in Oman for the TTR31

Field instruments in Oman are exposed to strong sun, high ambient temperature, wind-blown dust and, on coastal plants, salt in the air. When you specify the TTR31, check the ambient and process temperature limits, the enclosure rating and the wetted and housing materials against the actual installation point, and consider sunshades for transmitters mounted in direct sunlight. Cable entries should be sealed with suitable glands so that dust and moisture cannot enter the housing.

Calibration and verification planning matters as much as selection. Record the range, configuration and tag data of each TTR31 at commissioning, define a check interval that suits the criticality of the loop, and keep the certificates with the plant documentation so that audits and shutdown work can proceed without delay.

Documents and quotation

A copy of the manufacturer technical information for the TTR31 is attached on this page so you can check ranges, connections and ordering codes against your specification. The attached document also covers the hygienic TTR35.

Send the full order code or the process data (fluid, temperature, pressure, line size or tank data, output and approvals) and Seven Star LLC will prepare a quotation and confirm lead time. We are an independent supplier in Muscat and do not represent the manufacturer.