Specifications

6
Data Type Structure Section 1-4
All other addresses
The count value is interpreted in BCD-code. This allows transfer of this value within
the PLC program to the counter by means of the accumulator. This service should
be used for indirect write-operations of count values since the values are available
in the Siemens conforming format.
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 timers, the terminal converts the time value and time base
into a terminal-internal unsigned 4-byte variable 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 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, a terminal-internal unsigned 4-byte value
is converted to a time value and the smallest possible time base.
In addition, a distinction is made between variables which have been assigned a
timer address or another PLC address.
Timer address
When accessing timer addresses, the time value is interpreted in binary format. To
avoid timer control bits from being erased, this service should be used in the read-
mode only.
All other addresses
The time value is interpreted BCD-coded. Because the values are available in the
Siemens conforming format, this service should be used for indirect write-oper-
ations of time values.
d) Floating Point Number
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-conforming byte order for
words.
Data with a length of 4 bytes are interpreted in the PLC-conforming byte order for
long words.