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21  DEVICES
21.3  User Device
■Long timer (LT/LST)
In the following program, the accuracy of Tp (the time duration from the long timer coil activation to long timer contact 
activation) is (Ts-Tu)  Tp < (Ts + Tu).
(1) Cp is updated.
(2) LT0 is initialized to 0.
(3) The result of (Ct - Cp) is added.: 0 + (12 - 10) = 2
(4) The result of (Ct - Cp) is added.: 2 + (13 - 12) = 3
(5) The result of (Ct - Cp) is added.: 3 + (15 - 13) = 5
Tp: time duration from the long timer coil activation to long timer contact activation
Ts: setting value of the long timer
Tu: time limit value of the long timer
ON
ON
10 11 12 13 14
10 12
02
15
13
3
15
5
ON
ON
16 17
(1)
(2) (3) (4) (5)
(1) (1)
M0
LT0 (coil)
LT0 (contact)
M1
Previous count value 
of LT0 (Cp)
Current value of LT0
Counter used in system 
(Ct)
LT0 coil 
Execution of 
(OUT LT0 instruction)
M1 coil 
Execution of 
(OUT M1 instruction)
Process value of LT0 (Tp)