User's Manual

Table Of Contents
Page III-48 SITRANS LR 460 (PROFIBUS PA) – INSTRUCTION MANUAL 7ML19985JM01
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PA: Remote Operation
Cyclic Data
When you configure SITRANS LR 460 on the PROFIBUS PA bus, there are two slots
available for modules.
Slot 0 always transmits AIFB1 information
1
; slot 1 defaults to Free Place, but can be
changed to AIFB2 information. If you do not wish to have data transmitted, then you must
use a Free Place module in that slot.
Each of the two Analog Input Function Blocks can be set up to return Level, Distance, or
Volume. Within the function blocks, the values are scaled according to the user
requirements (see
Analog Input Function Blocks 1 and 2
on page 55 for details).
AIFB1 and AIFB2 return 5 bytes of data each:
The first 4 bytes are the floating point representation (IEEE) of the variable. The variables
are the outputs of the function block. The 5th byte is the status word and the list of
possible values is given in the chart below.
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.
Status Byte
Note: Each of the slots has to have a module defined in it.
1.
See
Analog Input Function Blocks 1 and 2
on page 55 for more information.
Status Codes for Good Quality
Values in hex notation Description
0x80 Data is GOOD.
0x84
A parameter in the function block has been changed: status
active for 10 s
0x89 Active low warning.
0x8A Active high warning.
0x8D Active low alarm.
0x8E Active high alarm.
Floating Point Status
AIFB2
AIFB1 byte 1 byte 2 byte 3 byte 4 byte 5
byte 6 byte 7 byte 8 byte 9 byte10byte10