PROFIBUS Controller SPC 4®-2 LF
82
C79000-G8976-C157-3
7.2 Fail-safe
Mode
An additional mode register bit "Spec-Clear-Mode" (bit 5 in mode register 2),
enables the fail-safe mode. The fail-safe mode is enabled by setting "Spec-Clear-
Mode = 1".
The "IND-N-Cleared" and "IND-U-Cleared" bits are added to the access byte of the
default SAP:
Access byte( 3..0)
:= Access-Value
Access byte (4)
:= RUP-N-Valid
Access byte (5)
:= IND-N-Valid
Access byte (6) :=
IND-N-Cleared
Access byte (7) :=
IND-U-Cleared
Bit Position
Meaning
7
6
5
4 3 2 1 0
IND-U-Cleared IND-
N-
Clear
ed
IND-
N
Valid
RUP-
N
Valid
Access Value
Access-Byte
Bits 0-
3
Access value
Bit 4
RUP-N-Valid (only with DEFAULT-SAP)
Bit 5
IND-N-Valid (only with DEFAULT-SAP)
Bit 6
IND-N-Cleared (only with DEFAULT-SAP)
The "IND-N-Cleared" bit can only be evaluated when "IND-N-Valid = 1" is set.
If "IND-N-Valid = 1" is set, then:
The output data in indication buffer N can be adopted.
The output data in indication buffer N must be replaced by the corresponding clear
coding. The last received output data are entered in indication buffer N.
Bit 7
IND-U-Cleared (only with DEFAULT-SAP)
The "IND-U-Cleared" bit must be set by the user on entering the fail-safe status and
reset when the fail-safe status is exited. The SPC 4-2 does not modify this bit. The SPC
4-2 does, however, scan the bit when "Spec-Clear-Mode=1" is set and a "Read-Output-
Data" frame is received in the DP mode.
If the application is not in the fail-safe state; in other words the application uses the
data of indication buffer U as the output data. If "Spec-Clear-Mode = 1" is set, the
user must reset "IND-U-Cleared=0" to update the output data when "IND-N-Valid=1"
and "IND-N-Cleared=0" are set.
If the application is in the fail-safe state; in other words the application uses the clear
coding as output data. The data in indication buffer U are then invalid. If "Spec-Clear-
Mode = 1" is set, the user must set "IND-U-Cleared=1" to update the output data
when "IND-N-Valid=1" and "IND-N-Cleared=1" are set.
Table 7-18 : Fail-safe Mode
Содержание SIMATIC NET SPC 4-2 LF
Страница 9: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 9 Introduction 1 ...
Страница 11: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 11 Functional Overview 2 ...
Страница 14: ...PROFIBUS Controller SPC 4 2 LF 14 C79000 G8976 C157 3 ...
Страница 15: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 15 Pin Assignment 3 ...
Страница 18: ...PROFIBUS Controller SPC 4 2 LF 18 C79000 G8976 C157 3 ...
Страница 19: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 19 Memory Assignment 4 ...
Страница 32: ...PROFIBUS Controller SPC 4 2 LF 32 C79000 G8976 C157 3 ...
Страница 33: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 33 FLC Interface 5 ...
Страница 50: ...PROFIBUS Controller SPC 4 2 LF 50 C79000 G8976 C157 3 ...
Страница 51: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 51 DP Interface 6 ...
Страница 63: ...ASIC Interface PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 63 ASIC Interface 7 ...
Страница 107: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 107 Asynchronous Interface 8 ...
Страница 114: ...PROFIBUS Controller SPC 4 2 LF 114 C79000 G8976 C157 3 ...
Страница 115: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 115 Synchronous Interface 9 ...
Страница 125: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 125 Clock Pulses 10 ...
Страница 128: ...PROFIBUS Controller SPC 4 2 LF 128 C79000 G8976 C157 3 ...
Страница 129: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 129 Processor Interface 11 ...
Страница 152: ...PROFIBUS Controller SPC 4 2 LF 152 C79000 G8976 C157 3 ...
Страница 153: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 153 Technical Specifications 12 ...
Страница 159: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 159 Package 13 ...
Страница 165: ...Package PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 165 Figure 13 4 Tray Spezification ...
Страница 166: ...PROFIBUS Controller SPC 4 2 LF 166 C79000 G8976 C157 3 ...
Страница 168: ...PROFIBUS Controller SPC 4 2 LF 168 C79000 G8976 C157 3 ...
Страница 169: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 169 Addresses 15 ...
Страница 172: ...PROFIBUS Controller SPC 4 2 LF 172 C79000 G8976 C157 3 ...
Страница 173: ...PROFIBUS Controller SPC 4 2 LF C79000 G8976 C157 3 173 Appendix 16 ...
Страница 178: ...PROFIBUS Controller SPC 4 2 LF 178 C79000 G8976 C157 3 ...