CIRCUIT FOR PREVENTING THE NUMBER OF CHARACTERS SET UP ON THE KEYBOARD FROM DEVIATING FROM THE DIGIT CAPACITY IN DATA-ACQUISITION AND ACCOUNTING MACHINES

摘要

1286098 Error detection KOMBINAT ZENTRONIK VEB 2 Sept 1969 43423/69 Heading G4A A data acquisition or accounting machine has a circuit for preventing deviation between the number of characters set up on the machine keyboard and a machine place capacity pro. grammed by a unit P. The number of digits entered on the keyboard is counted on a 4 stage flip-flop binary counter (M1-M4) operating on modulo 16, the number of digits programmed is entered from the unit P and the two numbers feed comparison circuits V 1 -V 4 . If the digits entered are too numerous the unit ST responds, the machine cycle is not released when a start button is pressed, and the numbers must be entered again after clearing the counter with a correction key. The highest power digit (2SP3/SP) is compared first using the comparator V4 and, if the programme signal A4 and the counter signal A4 are equal, comparison is shifted to the (2SP2/SP) comparator V3 and so on. If they are not equal the AND gate UG5 controls the unit ST. The comparators also check that the number of places coincide using the AND gate UG1.