Description
The TEMA is a screw-in temperature sensor with a type K thermocouple, manufacturer type Müller METS-TS.
It combines sensor, amplifier, display and two limit contacts in one housing: one device at the process connection, one signal to the control system, one value to read on site. A separate transmitter in the control cabinet becomes unnecessary.
The thermocouple is a type K (NiCr-Ni) with a tolerance of ±1.5 °C to DIN EN 60584-2 class 1. The measuring range runs from -50 … +200 °C with a minimum span of 50 °C. Amplifier accuracy is 0.3 % of the range at 16 bit resolution, the measuring rate 10 measurements per second, the response time 20 ms; the filter is adjustable from 0 to 99 s and the transfer characteristic is linear with temperature.
The output is 4 … 20 mA with a superimposed HART signal in the 2-wire current loop, current range 3.8 … 20.5 mA, fault signal 3.6 mA on short circuit and 21 mA on break. Supply is 12 … 40 VDC from the loop, with reverse polarity protection. Setting is done with the keys at the display or over HART. The two limit contacts are PNP or NPN, 30 VDC / 200 mA, optionally 1000 mA.
Mechanically: process connection from 1/4" to 1" as well as 1/4NPT to 1/2NPT, protective tube in 1.4571, Ø 6 × 0.5 mm, 100 mm neck tube optional, insertion lengths from 50 to 1000 mm, PBT GF30 housing, polycarbonate display top, system pressure PN 25, protection at least IP 65 with encapsulated boards, any mounting position.
Two points for sizing. The ambient temperature is not the medium temperature. The medium may reach +200 °C, the electronics in the head only -20 … +80 °C – the manufacturer states explicitly for this series that temperatures above +85 °C can destroy the electronics. And: which connector carries how many limit contacts is not a free choice. Ten connections are available, but two contacts are only possible on M12 five- and eight-pin, on MIL and on the cable version.
Programming requires the DEV-KMA configurator with the TrComm software. No CE marking is documented in the manufacturer's data sheet and no declaration of conformity is available. The Ex version of this design is the TEMD (METS-WTEx).
Advantages at a glance
- Type K thermocouple, ±1.5 °C to DIN EN 60584-2 class 1
- Medium -50 to +200 °C, minimum span 50 °C
- 4 … 20 mA with HART in the 2-wire loop
- Accuracy 0.3 % of the range, 16 bit
- Display and keys on the device, plus HART
- Two limit contacts, PNP or NPN
- Protective tube 1.4571, insertion lengths 50 to 1000 mm
- System pressure PN 25, protection at least IP 65
- Ten electrical connections to choose from