Description
The TXMA is a rail temperature sensor for railway applications. It measures the temperature of the running rail and provides the measured value that controls the point heating system.
The housing fits rail profiles S 49, S 54, UIC 60, and R 65 without modification. It is fastened with a clamp and counter-clamp using an M10 threaded rod of strength class 10.9, tightening torque 68 Nm; installation must be below the heating element, otherwise, the sensor will measure the heating system instead of the rail. The housing measures 68 × 64 mm, is fully potted, made of material x 25 CrNiSi 18.9 and weighs approximately 1.5 kg; the operating temperature ranges from -40 … +85 °C, optionally -50 … +105 °C.
There is no plug: The connection cable H07BQ-F, 2 × 1.5 mm² is led out of the potting via a PG 11 screw connection. The output is galvanically isolated, the insulation voltage is 1500 VAC for 60 s – in the track, where traction currents and return current flow, this is the decisive value.
A Pt100 in 4-wire Class A configuration is installed in the housing as the measuring element. The measuring range is configurable and set ex works to -30 … +60 °C, the resolution is 0.1 °C, and the measurement deviation is less than ±0.05 % of the measuring span. The output is 4 … 20 mA in 2-wire technology, reversible to 20 … 4 mA, with output limits 3.8 … 20.5 mA according to NAMUR. The sensor is powered with 9 … 36 VDC.
Note before ordering: A railway standard is not documented – the sheet refers to a "Technical Approval from Deutsche Bahn AG" but does not provide a number or date, and EN 50121, EN 50155, and EN 45545 are not mentioned; proof of compliance must be requested from the manufacturer before use in railway applications. The 1500 VAC for 60 s is insulation voltage, not continuous operating insulation; an overvoltage category and lightning protection are not specified. The data sheet does not state a degree of protection – the housing is fully potted, an IP code is missing. To change the measuring range, the configuration set with DTM-Control software is required, connection via RS 232-C; if configured during operation, the connection to the point heating control is interrupted, and whether the set is still available must be clarified with the manufacturer. A CE mark and explosion protection are not documented.
Advantages at a Glance
- Fits S 49, S 54, UIC 60, and R 65 without modification
- Pt100 4-wire Class A, resolution 0.1 °C
- 4 … 20 mA, reversible to 20 … 4 mA, limits 3.8 … 20.5 mA according to NAMUR
- Galvanically isolated, insulation voltage 1500 VAC for 60 s
- Housing 68 × 64 mm stainless steel, fully potted, approx. 1.5 kg
- Clamp with M10 threaded rod, tightening torque 68 Nm