Different Coil Type Timers used in Siemens PLC Programming

There are 5 different coil type timers used in PLC ,
ON Delay Timer Coil: This is the notation used in PLC for this timer. ON delay timer coil used for delaying ON condition of the output. This output coil type timer needs one extra input contact (T0) to turn on its output. Reset coil from bit instructions needs to use separately to reset the timer.
OFF Delay Timer Coil: This is the notation used in PLC for this timer .OFF delay timer coil used for delaying the OFF condition of the output. This output coil type timer needs one extra input contact (T0) to turn on its output. Reset coil from bit instructions needs to use separately to reset the timer.
Pulse Timer Coil: This is the notation used in PLC for this timer .When Timer receives a positive pulse from the input, it enables and using the timer input contact it enables output coil. The timer will be in ON condition as long as the input condition is ON or accumulator value reaches the preset value. If the input changed from “1 to 0” before the time interval has elapsed, the timer stopped along with disabling output. Reset coil from bit instructions needs to use separately to reset the timer.
Extended Pulse Coil: This is the notation used in PLC for this timer . When Timer receives a positive pulse at the input, it enables the output as long as the preset value set for the timer. The signal state at the output is at “1” as long as the timer is running. If the input to the timer changed from “1 to 0” before the time interval has elapsed, the timer continues to run and enables output until the accumulator value reaches a preset value. Reset coil from bit instructions needs to use separately to reset the timer.
Retentive ON Delay Timer: This is the notation used in PLC for this timer . Same as ON delay timer except it does need input condition to remain ON. It needs one single pulse to turn ON a timer. Reset coil from bit instructions needs to use separately to reset the timer.

As per the below Tabular form, the upper question marks are the timer number (T0, T1, T2,….) and the lower question marks are the timer preset value.