Fieldbus temperature multiplexer cuts costs by 70%

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MTL is launching the 9331-TI fieldbus multiplexer, a field-mounted temperature input block for two- and three-wire RTDs, thermocouple, voltage and resistance inputs, with each unit supporting eight independently configurable temperature inputs. The 9331-TI can save costs in temperature monitoring applications such as complex machinery, distillation columns, tanks, reactors and boilers. It can reduce installed costs by as much as 70 per cent per point in comparison with traditional single-temperature inputs.

The 9331-TI is bus-powered, operating between 9 and 32Vdc, requiring a maximum current of only 22mA. Traditional temperature monitoring methods (control system temperature input cards, low-cost single-input transmitters and remote I/O) are superseded by this intrinsically safe, eight-input multiplexer that mounts beside the process, and the use of Foundation fieldbus enables easy integration with process control systems.

As a Foundation fieldbus device, measurement status is available (good, bad or uncertain) as well as sensor failure indication. The 9331-TI fieldbus function block support includes eight analogue input (AI) blocks, an eight-channel multiple analogue input (MAI) block, and an input selector (IS) block providing basic logic such as minimum, maximum, mid-point or average temperature.

Designed for the harshest environments, the multiplexer has hazardous area certification and intrinsically safe inputs when connected to an IS fieldbus spur, or non-incendive Ex nL inputs when connected to a non-arcing Ex nA or non-incendive Ex nL fieldbus spur. It may be installed in a Zone 0 (gas) Class 1 Division 1 hazardous area or, when mounted in specific process junction boxes, in a Zone 20 (dust) hazardous area. This flexibility, when combined with an operating temperature range of -40 to +85degC and input-to-input isolation of 500V AC rms, means that the multiplexer can be mounted close to the process.

The multiplexer may be housed in a variety of field enclosures to suit end-user requirements, with a range of standard, single/dual-unit glass-reinforced polyester and single-unit stainless steel enclosures available. A custom systems capability will satisfy projects that require more than one TI multiplexer per enclosure or combinations of fieldbus barriers, TI multiplexers and ancillary components.

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