TON : Turn-On Delay Function Block

Introduction

TON commonly used as the On Delay. When the function block (FB) is called for the first time, the initial state of Internal Time ET is “0”. EN and ENO can be configured as additional parameters. 

EN (ENable)	ENO (Error NOtification)
It is an optional block input. When then EN input is enabled so ENO output is set automatically. If EN = 0 (the block is not enabled) its internal program is not executed and ENO is set to 0. If EN = 1, the block’s internal program is run and ENO is set to 1. If an error occurs, ENO is set to 0. If the EN input is not connected, ENO is set automatically to 1.	This is an output associated with an optional input EN. If ENO is set to 0 (because EN = 0 in case of an execution error):  - The status of the function block outputs remains the same as it was during the previous scanning cycle that executed correctly. - The output(s) of the function as well as the procedures, are set to “0”.

Function Description

- IN and PT are input variables of the BOOL and TIME types respectively.

- Q and ET are output variables of the BOOL and TIME types respectively.

- If IN is FALSE, Q also FALSE and ET is 0.

- Once IN become TRUE time will start to be counted in miliseconds in ET until its value is equal to PT.

- Then, it will remain constant 

Represent in:

1) Function Block Diagram (FBD)

2) Ladder Diagram (LD)

3) Instruction List

4) Structured Text (ST)

Description of Input/Output Parameters

	PARAMETER	DATA TYPE	MEANING
INPUT	IN	BOOL	Start delay
	PT	TIME	Preset delay time
OUTPUT	Q	BOOL	Output
	ET	TIME	Internal time

Description of Data Type

DATA TYPE
BOOL	TIME
BOOL is the short form for the Boolean type. This is the basic data type in computing. A BOOL variable can have two condition:        0 (FALSE)        1 (TRUE) A bit extracted from words is of type BOOL.        eg: %MW12.7	TIME type present a time in miliseconds. Encoded in 32 bits, this type can be used to obtain times from 0 to 232 -1 miliseconds. TIME has the following units in: days (d), minutes (m), seconds (s) and miliseconds (ms). A literal value of TIME is represented by a combination of the preceding types prefixed with T#, t#, TIME# or time# eg: T#25h15m, t#14,7S, TIME#5d10h23m45s3ms

Timing Diagram

Representation of the ON delay TON:

(1) If IN becomes “1” so the internal time (ET) starts.

(2) If the ET reaches the value of PT, Q becomes “1”.

(3) If IN “0” so Q becomes “0” and the internal time is stopped/reset.

(4) If IN “0” before the ET has reached the value of PT, the ET stops/resets without Q going “1”

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