Principles of naval engineering - Historic Naval Ships Association

PRINCIPLES OF NAVAL ENGINEERING(1) Differential Pressure-to-Current Transmitter(2) Pressure-to-Current Transmitter(3) Float Switch(4) Differential Pressure Switch(5) Pressure SwitchFigure 25-20.— Pressure and Level Sensors.140.92program contact, controlled by the scanner, setsup the comparison values for the signal as wellas any adjustments to the signal required duringconversion and scaling.If the information is requested and/or thepoint is in alarm, the A/D converter then transfersthe values via the Word Distributor (24) tothe scaling module. If neither of the previouslymentioned conditions exist, the scanner executesbranch back and picks up the next address andrepeats the process.After the information leaves the A/D converterit is sent to the scaling module whichscales all signals into a zero to 1000 scale. Thisinformation is in the form of pulses numberingfrom zero to 1000 according to the value of theinput signal to the A/D converter. The addressinformation is then placed in the necessary registersand along with inputs from the Real TimeClock (40) and Digital Inputs (43) and made readyto be sent to the log Printout Buffer (37) and onto the Typewriter Drive (38) for printing.648