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Richmond, North Yorkshire, DL10 5NY

Temperature Multiplexer


The Temperature Multiplexer is a multi-spot temperature transmitter capable of accepting up to 16 RTD inputs, intended for use within hazardous areas. It presents a unified Modbus, GPU or Current Loop interface to the control systems, for larger numbers of RTDs, multiple units can be multi dropped seamlessly onto the same field bus as other devices such as level gauges.

Used in conjunction with our Mini Receiver and LMS software the TM188 provides a simple, proven skin temperature monitoring system used during the cooldown commissioning phase of dozens of LNG tanks the world over. 

Over 84 Sytems Worldwide 
Years trusted by customers
Year launched 

Temperature Multiplexer

LMS LNG tank inventory


Key features
  • Multi-spot temperature transmitter capable of accepting up to 16 RTD inputs in a single unit.
  • Capable of multi-dropping on to a field bus to support more temperature sensors.
  • Performs measurements locally, and can share level gauge buses reducing the amount of expensive cabling required.
  • ATEX/IECEx Hazardous Area Zone 1 certified.
  • GOST certified
  • Large installed base of sites from the Artic to the Equator
  • Supports redundant designs for increased resilience
Compatible gauge manufacturers
  • Endress+Hauser
  • Honeywell Enraf
  • Whessoe
  • Emerson Rosemount (Saab)
  • Scientific Instruments
  • Endress+Hauser Multiscan
  • Mini Receiver
  • Endress+Hauser Tankvision LMS
  • MHT Technology LMS
  • Honeywell Enraf Entis LNG Pro



Significant cost reductions are made using this device by eliminating runs of expensive cabling from the hazardous area to the safe area for each RTD. Instead, the measurements are performed locally and transmitted over a 2 wire digital field bus. System resilence can be increased by providing dual redundant field bus ports.


A number of protocols and field bus technologies are supported allowing the unit to be integrated with old legacy systems or more modern open systems. By connecting the devices to cable runs for other field instruments (e.g. level gauges) cabling costs can be reduced. Supported protocols include, but are not limited to, Enraf BPM, RS485, and Current Loop.


The internal electronics scale and amplify the input signals before a precision analogue to digital converter, under the control of the processor, digitises the measurements and converts them to engineering units. Each intrinsically safe sensor will be continuously scanned and its temperature calculated and stored in an in-memory real-time database. The unit is given a unique address by which it can be polled from a host system such as LMS.




No other analogue-digital multi-channel interface holds certification for IECEx, ATEX, and GOST for Zone 1. Produced in the UK from a manufacturer with over 15 years experience of designing and manufacturing solutions for explosive atmospheres.


The unit is ATEX, IECEx and GOST approved for installation into a Zone 1 hazardous area. The unit has many applications for accurate measurement within a hazardous or non-hazardous area but has been specifically designed for temperature measurement requirements within a tank gauging system designed for bulk measurement of oil and gas. Petroleum storage installations such as Refineries, Marketing / Distribution Terminals, and Liquified Gases. 

Natural Gas (LNG) storage facilities use these devices for skin temperature measurement. The two field bus ports help to support the redundant architectures often demanded by LNG applications, and each port can be polled simultaneously for data by two independent host systems if necessary. Field bus interfaces are available for a range of host systems. 

find out how THE temperature multiplexer can help your site today


temperature multiplexer

Multi-spot temperature transmitter capable of accepting up to 16 RTD inputs, intended for use within hazardous areas.