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For distributed temperature sensing often a code correlation technology [2] [3] [4] is employed which carries elements from both principles. OTDR was developed more than 20 years ago and has become the industry standard for telecom loss measurements which detects the—compared to Raman signal very dominant— Rayleigh backscattering signals.
[8] [9] The fiber-optic sensor is well suited for this environment as it functions at temperatures too high for semiconductor sensors (distributed temperature sensing). Optical fibers can be made into interferometric sensors such as fiber-optic gyroscopes , which are used in the Boeing 767 and in some car models (for navigation purposes).
2 Catalyst Temperature: Bank 2, Sensor 1 3E: 62: 2 Catalyst Temperature: Bank 1, Sensor 2 3F: 63: 2 Catalyst Temperature: Bank 2, Sensor 2 40: 64: 4 PIDs supported [$41 - $60] Bit encoded [A7..D0] == [PID $41..PID $60] See below: 41: 65: 4 Monitor status this drive cycle Bit encoded. See below: 42: 66: 2 Control module voltage 0 65.535 V
For example, a temperature-controlled circulating bath has two PID controllers in cascade, each with its own thermocouple temperature sensor. The outer controller controls the temperature of the water using a thermocouple located far from the heater, where it accurately reads the temperature of the bulk of the water.
Level 3 is the production control level, which does not directly control the process, but is concerned with monitoring production and monitoring targets; Level 4 is the production scheduling level. Levels 1 and 2 are the functional levels of a traditional DCS, in which all equipment are part of an integrated system from a single manufacturer.
The control action is the switching on/off of the boiler, but the controlled variable should be the building temperature, but is not because this is open-loop control of the boiler, which does not give closed-loop control of the temperature. In closed loop control, the control action from the controller is dependent on the process output. In ...
If the process requires a very fast response to temperature changes (fractions of a second as opposed to seconds), then a thermocouple is the best choice. Time response is measured by immersing the sensor in water moving at 1 m/s (3.3 ft/s) with a 63.2% step change. Size
Direct digital control is the automated control of a condition or process by a digital device (computer). [ 1 ] [ 2 ] Direct digital control takes a centralized network-oriented approach. All instrumentation is gathered by various analog and digital converters which use the network to transport these signals to the central controller.