Specifications

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Data Type Structure Section 7-4
7.4 Data Type Structure
a) Alphanumerical Text
Is stored in the memory byte for byte in ascending address order.
b) Counter
The count value is interpreted in binary format. The maximum value is 8191.
c) Timer
Timer functions consist of a time value and a time base. The terminal operates with
imaginary unsigned 4-byte variables, even though the data stored in the PLC com-
prise only 2 bytes.
When read-accessing the timer, the terminal converts the time value and time base
into a terminal-internal unsigned 4-byte number, which represents the time value in
reference to the time base of 0.01 second.
Example: A range of 10 (time base is 1.0 second) and a time value of 999, are
represented or edited, respectively, in the terminal by the value 99900. Scaling of
this value to other value ranges is possible by specifying a factor and divisor within
the variable definition.
Before writing a timer variable to the PLC, the time value and the smallest possible
time base are formed from the terminal-internal unsigned 4-byte value.
d) Floating Point Numbers
The data are interpreted in the Siemens floating point format.
e) Binary Variables with a Length of 1, 2 or 4 Bytes
Data with a length of 2 bytes are interpreted in the PLC-conformal byte order for
words.
Data with a length of 4 bytes are interpreted in the PLC-conformal byte order for
long words.
7.4.1 Data Types
Direct accessing of the following data types is possible:
E Input B, BY, W, DW
A Output B, BY, W, DW
M Flag B, BY, W, DW
T Timer (R300 and R600 read-only) W
Z Counter (R300 and R600 read-only) W
D Data word (0 to 510) W, DW
DP Data buffer (0 to 510 ; only ZE300) W
The size of each data area is governed by the CPU of the PLC.