Table 7.1 (continued) 49 Name of the mode Input functions Principle of operation Illustration Input 4 - block • if both the setpoints have the same sign t1, t2 – moments of change of the counting direction (the appearance of the pulse at the counting input 2); t3 – moment of switching of output 2 in case of coincidence of values of the counting register and setpoint 2; t4 – moment of switching of output 1 in case of coincidence of values of the counting register and setpoint 1