Specifications

CPU Memory: Data Types and Addressing Modes
5-7
S7-200 Programmable Controller System Manual
C79000-G7076-C233-01
Addressing the Timer (T) Memory Area
In the S7-200 CPU, timers are devices that count increments of time. The S7-200
timers have resolutions (time-base increments) of 1 ms, 10 ms, or 100 ms. There
are two variables that are associated with a timer:
 Current value: this 16-bit signed integer stores the amount of time counted by
the timer.
 Timer bit: this bit is set or cleared as a result of comparing the current and the
preset value. The preset value is entered as part of the timer instruction.
You access both of these variables by using the timer address (T + timer number).
Access to either the timer bit or the current value is dependent on the instruction
used: instructions with bit operands access the timer bit, while instructions with
word operands access the current value. As shown in Figure 5-3, the Normally
Open Contact instruction accesses the timer bit, while the Move Word (MOV_W)
instruction accesses the current value of the timer. For more information about the
S7-200 instructions, see Chapter 9 for SIMATIC instructions and Chapter 10 for
IEC 1131-3 instructions.
Format: T [timer number] T24
Current Value
T0
T3
T0
Timer Bits (Read/Write)
T1
T2
T1
T2
T3
I2.1
MOV_W
EN
OUT VW200INT3
T3
Area identifier (timer)
Timer number (bit address)
Timer number
(current value address)
Area identifier (timer)
15
MSB
LSB
0
Current Value of the Timer
(Read/Write)
T0
T3
T0
Timer Bits
T1
T2
T1
T2
T3
Figure 5-3 Accessing the SIMATIC Timer Data