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5.3.2
Structure of the Indication Block
Response header
Byte 0
resp-
This pointer points to the swapped-out response buffer (in the reply-on-indication-blocks
buf-ptr
area, refer to the memory area distribution). It is copied by the SPC 4-2 from the SAP list.
Byte 1
indic-
Here, the SPC 4-2 enters the status 00 for a 'valid indication'.
status
Request header (frame header characters of the requester)
Byte 2
req-
This value specifies the length of the net data entered in the request buffer (0 to 244 bytes
data-
with SAP extension, 0 to 246 bytes without SAP extension).
length
Byte 3
rem-
Here, the SPC 4-2 enters the received SA. The remote node that will be involved in data
adr
exchange with the relevant service access point of the local station. It can be specified as a
filter in req-sa in the SAP lists.
Byte 4
loc-adr
Here, the SPC 4-2 enters the received DA.
Byte 5
co-
This value specifies the function code of the request frame. Here, the complete control octet
code
is entered as received from the bus.
Function
Request FDL Status with Reply
Send Data with no Acknowledge low
Send Data with no Acknowledge high
Send Data with Acknowledge low
Send Data with Acknowledge high
Send and Request Data low
Send and Request Data high
SM_Time
SM_SRD
SM_SDN
SM_SRD_SLOT_DEL
SM_SRD_SLOT_KEEP
Send and Request Data with DDB
DDB-Response low
DDB-Response high
x: Frame type 1 meaning bit 6=1 and FCB/FCV according to frame entry
y: Frame type 0 meaning bit 6=0 and station type 2 according to frame entry
Bit 7 (b8) of the received control octet is only evaluated for SM time frames, with all other
request frames, bit 7 (b8) of the control octet is don't care.
Byte 6
rem-
Here, the SPC 4-2 enters the service access point (SSAP) of the remote node. This field is
sap
only valid when the extension bit in rem-adr is set (the higher two bits of the rem-sap must
be '0'). If a frame is received without a SAP extension (rem-SAP, loc-SAP) the SPC 4-2
enters 0FFh.
Byte 7
loc-sap
Here, the SPC 4-2 enters the service access point (DSAP) of the local node. This field is
valid only when the extension bit in rem-adr is set. If a frame is received without a SAP
extension (rem-SAP, loc-SAP) the SPC 4-2 enters 0FFh.
Request buffer contains the received frame
Byte 8
data 0
Byte
data 0+x
8+x
Table 5-7 :
Indication Block
2
Note: The station type with PROFIBUS DP is bit 5 (b6) and bit 4 (b5). With PROFIBUS PA, bit 7 (b8) is also relevant.
46
Byte 0 of the net data
Byte x of the net data
Code
x9h
x4h
x6h
x3h
x5h
xCh
xDh
x0h
x1h
x2h
xAh
xBh
x7h
y8h
yAh
PROFIBUS Controller SPC 4®-2 LF
C79000-G8976-C157-3
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