Level-trol operation

The same sort of problem arises in a level-trol, which measures and transmits a process vessel liquid level to the control center. As shown in Fig. 6.3, the level-trol operates by means of two pressure transduc-... [Pg.60]

The same sort of problem arises in a level-trol, which measures and transmits a process vessel liquid level to the control center. As shown in Fig. 10.3, the level-trol operates by means of two pressure transducers, devices for converting a pressure signal into a small electric current. The difference between the two pressure transducers shown in Fig. 10.3 is called the milliamp (milliampere) output. This milliamp output is proportional to the pressure difference between the bottom and top taps in the level-trol. To convert the milliamp output signal from the level-trol into a level indication, the instrument technician must assume a specific gravity ... [Pg.111]

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