12.2.4.2
Diagnostics via input image
Table 12-28 Diagnostics input image
Byte
Bit7
Bit6
Bit5
Bit4
Bit3
Bit3
Bit1
Bit0
d+0
count_2
count_1
count_0
T_Alarm_2
T_Alarm_1
Diag_2
Diag_1
Diag_0
d+1
Status_1
Table 12-29 Messages in byte 0
Bit
Signal name
Message
7
count_2
alive and well 2
6
count_1
alive and well 1
5
count_0
alive and well 0
4
T_Alarm_2
Temperature not within the operating temperature range defined for the
module
3
T_Alarm_1
Critical temperature exceeded
2
Diag_2
Overload DO byte 5/4
1
Diag_1
Overload DO byte 3/2
0
Diag_0
Overload DO byte 1/0
Note
The "alive and well" counter is a 3 bit modulo counter at the PP application level. The PP
application can be monitored using this counter. Failure of the application software does not
generally result in a communication failure, as this is developed in a hardware-supported
manner. The watch dog switches off the digital outputs, while the inputs remain at their last set
values.
Table 12-30 Messages in byte 1, depending on the "alive and well" counter
"alive and
well" counter
Value
byte 1
Message
0
0
Reserved
1
Temperature value
2
5
Internal error, system error
Effect: The "PNFault" LED is activated. The outputs are disabled. The value
0x80 is stored in status byte 1.
Remedy: Switch the module off and on again.
3 ... 7
0
Reserved
Connectable components
12.2 PP 72/48D PN
NCU 1740
126
Equipment Manual, 10/2021, A5E51087503B AA