ABB Functional Block Diagram Timer Blocks - TON, TOF and TP

functional block diagram have on delay timer TON and OFF delay timer TOF. timer are most important instruction in plc programming. an on delay timer on output when elapsed time reached to preset value. off delay timer set output off when input of timer is changed from true to false and preset time is equal to elapsed time. both timer operation is same as ladder logic. maximum time that can we used for timer preset value is not greater than 49d17h2m47s295ms (4194967295 ms). if you already used on delay timer and off delay timer in ladder programming. both timer blocks have inputs and outputs. inputs and output of these timer as follows

input of timer
• IN :bool type timer input
• PT : time type preset value of timer you can use time constant like T#10s, T#1m etc.
output of timer
• Q : bool type output of timer
• ET : elapsed time output of timer use time data type

abb function block digram on delay timer TON

TON is on delay timer operator in abb plc for FBD. on delay timer delayed output to turn on when input variable of timer is changed from OFF to ON or false to true. instance name for on delay timer is TON. below is the example of on delay timer TON operator. preset value of this timer is 10 second(T#10S). when input of timer set to true than timer start and output is set to true when elapsed time is equal to preset value.

abb function block diagram OFF delay timer TOF

TOF is off delay timer operator in a FBD programming. input and output of off delay timer is same as on delay timer. off delay timer operation start when input of TOF changed from true to false or ON to OFF. OFF delay timer off output of timer when elapsed timer is equal to preset value.

above is the example of off delay timer, when input of off delay timer is turned on output is set to true and elapsed time remains zero. when input of off delay timer changed from on to off than timer start and elapsed time start increment when elapsed timer reached to preset value timer output is set to OFF and timer operation stop.

abb function block diagram Pulse timer TP

TP is pulse timer operator in functional block diagram. output of pulsed timer is set to true when elapsed time is less than preset time of timer. pulse timer used as a pulse generator for a specific time. specific time of pulse timer is preset time.

above is the example of TP pulse timer, output of timer is set to true only specific interval. preset is specific interval. in example preset time is 10 second when input of timer is changed from off to on than pulse timer start increment elapsed time value and output is turned on. when elapsed time is equal to or greater than preset time than output of pulse timer is turned off.