User's Manual

Page 132 SITRANS LR560 (PROFIBUS PA) – OPERATING INSTRUCTIONS 7ML19985LT01
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F: Communications PA
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
In PROFIBUS PA there are two possible types of status byte:
• condensed status: one of two status bytes defined in Profile Standard V3.01
• status byte: the status byte originally defined in Profile Standard V3.0
You can choose which type of status byte will be returned, by enabling or disabling
Condensed Status (3.5.)
Condensed Status
These codes are available when Condensed Status is enabled. See Condensed Status
(3.5.) on page 83 for more details.
Condensed Status (GOOD)
Hex
value
Status – GOOD Description
0x80 GOOD – ok No error or special condition is associated with this value.
0x84 GOOD – update event
Set if the value is good and the block has an active Update
event. (This status remains active for 20 seconds.)
0x86
GOOD – active advi-
sory alarm
Set if the value is good and the block has an active Alarm.
0x80
...0x8E
GOOD – limit check/
update event
See
Status Codes for Good Quality on page 134.
0xA0
...0xA3
GOOD – initiate fail
safe
This fault is not generated by the product, but can be simu-
lated.
Floating Point Status
AIFB2
AIFB1 byte 1 byte 2 byte 3 byte 4 byte 5
byte 6 byte 7 byte 8 byte 9 byte10byte10