Siemens sitrans LR 400 Instruction Manual page 92

The 2 function blocks (Level, Volume) return 5 bytes of data each:
Level byte 1
Volume
byte 6
The first 4 bytes are the floating point representation (IEEE) of the variable. The variables
are the outputs of the function block. The default setting for the variable level is meters.
The default setting for the variable volume is m
variables by changing the settings of the function block. This is typically done using PDM.
The 5th byte is the status word and the list of possible values is given in the chart on
page 89.
The 5 bytes must be read consistently, in a contiguous chunk: they cannot be read byte by
byte, and cannot suffer an interrupt. If you are using an S7-300/400, you will need to use
SFC14 DPRD_DAT: Read Consistent Data of a Standard PD Slave.
If you select a Free Place module to fill one of the slots, this will affect the byte number.
Example 1:
Free
Place
Volume
Example 2:
byte1
Level
Free
Place
Page 88
Floating Point
byte 2 byte 3
byte 7 byte 8
Floating Point
— —
byte 1 byte 2 byte 3
Floating Point
byte 2 byte 3
— —
SITRANS LR 400 – INSTRUCTION MANUAL
byte 4
byte 9
3
. You can change the settings of the
— —
byte 4
byte 4
— —
Status
byte 5
byte10 byte10
Status
—
byte 5
Status
byte 5
—
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