Your factory produces cryogenic refrigerators, and your task is to design a control system for the fridge, but, using the same sensor, you must also supply the end-user with temperature monitoring
Heat Exchangers
Heat exchangers are the types of equipment that are primarily employed to transfer the thermal energy from one fluid to another, provided that one of the fluids should be at a higher thermal energy content than the other fluid.
Heat Exchanger
The heat exchanger is a combination of two words ''Heat'' and ''Exchanger''. It is a mechanical device that is used to exchange heat energy between two fluids.
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Your factory produces cryogenic refrigerators, and your task is to design a control system for the fridge, but, using the same sensor, you must also supply the end-user with temperature monitoring. The cryogenic freezer is controlled in a tight band around minus 85°C, therefore in controlling the fridge you need to have the most accurate information available regarding the operating range of the fridge (nominally at -85°C, but it can be colder and it can defrost if faulty and reach a maximum ambient temperature of say 50°C to be safe).
Due to the economy of RTD sensors, it is decided by management to use a PT100 RTD sensor (range -400°F to 1200°F) with a smart transmitter which needs to be set up correctly to a 4-20mA input on the PLC controlling the fridge. Taking the above conditions into account, the measuring range should be -100°C to 50°C (which should cater for the worst ambient temperature).
a) Make sure the RTD is the correct choice b) Set the smart transmitter up correctly (type, offset and span) c) Find the straight-line equation (in the form y = ax+b, where y in mA, and x in °C) for the temperature in °C to mA output of the smart transmitter d) Test your equation at the extremes (-85°C to 50°C) |
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