Technical data

Testing with the Variable Table

20.4 Entering Variables in Variable Table

Programming with STEP 7

450 Manual, 05/2010, A5E02789666-01

20.4.4 Upper Limits for Entering Timers

Note the following upper limits for entering timers:

Example: W#16#3999 (maximum value in BCD format)

Examples:

Address Monitor Format Enter Modify Value

Display

Explanation

T 1 SIMATIC_TIME 137 S5TIME#130MS Conversion to milliseconds

MW4 SIMATIC_TIME 137 S5TIME#890MS Representation in BCD format possible

MW4 HEX 137 W#16#0089 Representation in BCD format possible

MW6 HEX 157 W#16#009D Representation in BCD format not

possible, therefore the monitor format

SIMATIC_TIME cannot be selected

Note

You can enter timers in millisecond steps but the value entered is adapted to the time frame. The size of the time

frame depends on the size of the time value entered (137 becomes 130 ms; the 7 ms were rounded down).

The modify values for addresses of the data type WORD, for example, IW1, are converted to BCD format. Not

every bit pattern is a valid BCD number, however. If the entry cannot be represented as SIMATIC_TIME for an

address of the data type WORD, the application reverts automatically to the default format (here: HEX, see Select

Monitor Format, Default Command (View Menu)) so that the value entered can be displayed.

BCD Format for Variables in the SIMATIC_TIME Format

Values of variables in the SIMATIC_TIME format are entered in BCD format.

The 16 bits have the following significance:

Bits 15 and 14 are always zero.

Bits 13 and 12 (marked with xx) set the multiplier for bits 0 to 11:

00 => multiplier 10 milliseconds

01 => multiplier 100 milliseconds

10 => multiplier 1 second

11 => multiplier 10 seconds

Bits 11 to 8 hundreds (hhhh)

Bits 7 to 4 tens (tttt)

Bits 3 to 0 units (uuuu)