Test/Commissioning/
Diagnostics
74
06/99 AWB 2700-1364 GB
PS 4-271 as slave: scan of master states
When used as a slave, the PS 4-271 is also a basic
unit with its own program and configuration.
Consequently, the diagnostic bytes described in
and
can also be scanned in this case. In addition,
the states of the master can be scanned by means of
the diagnostic byte ISB2.
Structure of diagnostic byte ISB2
Bits 0, 3, 4, 5 and 7 not used!
Scan in user program of slave
LD AT %ISB0.0.0.2: Byte;
or
LD AT %IS0.0.0.2.1: BOOL;
(Halt communication)
LD AT %IS0.0.0.2.2: BOOL;
(Input length error)
LD AT %IS0.0.0.2.6: BOOL;
(No connection)
Display in Sucosoft S 40
You can examine and interpret the diagnostic bits in
the “Test and Commissioning” menu:
왘
Select ‹Test and Commissioning
➞
Connection
list
➞
Topology›.
Bit 7
6
5
4
3
2
1
0
Bit 1:
Halt communication
0 = master in Run
1 = master in Halt
Bit 2:
Input length error
0 = ok
1 = length error in message
Bit 6:
No connection
0 = ok
1 = no connection to master
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