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Many plants have process units where multipoint temperature sensor arrays are used to capture temperature profiles to detect hot-spots, or where multiple single temperature points are within close proximity. Multi-input temperature transmitters are ideal for applications where there are many temperature measurements clustered together. Applications include:

• High resolution temperature profiles of tanks using multipoint temperature sensor arrays for computation of density to calculate volume and mass of the product.
• High resolution reactor temperature profiles using multipoint temperature sensor arrays to identify hot-spots and channeling to prevent product or catalyst damage, and control reaction efficiency.
• Column temperature profile with sensors at every tray to optimize separation and product quality.
• Multiple points throughout a furnace to determine how efficiently the furnace uses energy to improve energy usage to reduce operating costs.
• Motor winding temperatures to ensure they are operating within specifications, thus extending service life and preventing unnecessary downtime.
• Bearing temperature on critical compressors, pumps, fans, agitators, and conveyor belts etc. to alert when they exceed suggested operating temperatures to prevent potential damage, cascading into shutdowns of larger processing equipment.
• Heat exchanger efficiency by measuring inlet and outlet temperatures for steam and product to detect degradation due to fouling to determine if cleaning is needed.
• Boiler tube surface temperature to detect slagging or soot deposits hampering heat transfer and predicting fatigue to prevent boiler shutdowns due to tube ruptures, improving efficiency and plant availability.

To condition these sensor signals in the past you used to have to decide between accuracy, using many single-point measurement transmitters, or low-cost using control system temperature input cards or temperature multiplexers. However, multi-input temperature transmitters provide both the precision of field mounted transmitters, and economy using wireless or using only a single pair of wires from the multi-input temperature to the junction box and is two-wire loop powered Thus, no separate electrical power is required. The solution can be intrinsically safe, non-incendive, and flame/explosion-proof, making it suitable for all hazardous areas. All sensor signals are carried on the same two wires or over the air.

Some reactors and heat exchangers around plants may not be continuously monitored, relying on manual data collection because they were never instrumented due to the high cost of temperature input cards and compensation wires, or single point transmitters, wiring, and analog input cards. Modern plants are now built with multi-input temperature transmitters at lower cost, and existing plants can be modernized with multi-input temperature transmitters where measurements are missing.

Around-the-clock automatic device diagnostics monitoring alerts personnel to problems like sensor failures.

The right temperature is important for the operation of many processes. The wrong temperature will impact plant throughput, quality, and yield. Temperature is also important for maintenance, as high temperature is a leading indicator of problems in motors and machinery. If left unattended, improper temperatures can result in plant downtime and maintenance costs. Deploying transmitters to cover these missing measurements therefore makes sense.

A single gateway can be used to integrate hundreds of temperature points into an existing control system.

Read about one such modernization case here:

http://www2.emersonprocess.com/siteadmincenter/PM%20Central%20Web%20Documents/QBRExxonMobil3feb.pdf

What other applications are there where there are multiple temperature points in close proximity of each other such that it would make sense to use temperature transmitters with 4 or 8 inputs?