Addressing The Timer (T) Memory Area; Accessing The Simatic Timer Data - Siemens SIMATIC S7-200 System Manual

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:
T3
I2.1
Figure 5-3
S7-200 Programmable Controller System Manual
A5E00066097-02
CPU Memory: Data Types and Addressing Modes
T [timer number]
Timer number (bit address)
Area identifier (timer)
MSB
MOV_W
EN
IN OUT
T3 VW200
Timer number
(current value address)
Area identifier (timer)

Accessing the SIMATIC Timer Data

Current Value
T0
T1
T2
T3
Current Value of the Timer
(Read/Write)
15
T0
T1
T2
T3
T24
Timer Bits (Read/Write)
T0
T1
T2
T3
Timer Bits
LSB
0
T0
T1
T2
T3
5-7