Siemens SIMATIC S7-1200 Manual page 60

Programming concepts made easy
5.3 Easy to use the powerful programming languages
The CTUD counts up or down by 1 on the 0 to 1 transition of the Count up (CU) or Count
down (CD) inputs. The figure shows a CTUD timing diagram with an unsigned integer
count value (where PV = 4).
• If the value of parameter CV (Current count value) is equal to or greater than the value
• If the value of parameter CV is
• If the value of parameter LOAD
Timers
You use the timer instructions to create programmed time delays:
● TP: The pulse timer generates a pulse with a preset width time.
● TON: The on-delay timer output Q is set to ON after a preset time delay.
● TOF: The off-delay timer output Q is reset to OFF after a preset time delay.
● TONR: The on-delay retentive timer output is set to ON after a preset time delay. Elapsed
● RT: Reset a timer by clearing the time data stored in the specified timer instance data
TP, TON, and TOF timers
have the same input and
output parameters.
The number of timers that you can use in your user program is limited only by the amount of
memory in the CPU. Each timer uses use the 16 bytes of memory:
Each timer uses a structure stored in a data block to maintain timer data. You assign the
data block when the timer instruction is placed in the editor. When you place timer
instructions in a function block, you can select the multi-instance data block option, the timer
structure names can be different with separate data structures, but the timer data is
contained in a single data block and does not require a separate data block for each timer.
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of parameter PV (Preset value), then the counter output parameter QU = 1.
less than or equal to zero, then
the counter output parameter QD
= 1.
changes from 0 to 1, then the
value at parameter PV (Preset
value) is loaded to the counter as
the new CV (Current count value).
If the value of the reset parameter
R is changes from 0 to 1, the
current count value is reset to 0.
time is accumulated over multiple timing periods until the R input is used to reset the
elapsed time.
block.
The TONR timer has
the additional reset
input parameter R.
The RT instruction resets
the timer data for the
specified timer.
"Timer name"
----[ RT ]----
Easy Book
Manual, 11/2009, A5E02486774-01