Siemens PPU 26x.3 series Manual page 225

Bit
3
2
1
0
Messages in byte 1 ("alive and well" counter)
Note
The "alive and well" counter is a 3-bit modulo counter on a PP application level. The PP
application can be monitored using this counter. Failure of the application software does not
result in a communication failure, because the communication is performed with hardware
support. The watchdog switches off the digital outputs, while the inputs retain their last values.
Overview of the messages in byte 1, depending on the "alive and well" counter:
"alive and
well" counter
0
1
2
3 ... 7
Correcting errors at counter value "2"
Value of
byte 1
1
2
PPU and components
Manual, 10/2015, 6FC5397-2DP40-5BA3
Signal name Message
T_Alarm_1 Critical temperature exceeded
Diag_2 Overload DO byte 5/4
Diag_1 Overload DO byte 3/2
Diag_0 Overload DO byte 1/0
Value of Meaning
byte 1
0 Reserved
Temperature value
0 No error
1 Impermissible input voltage in temperature measurement mode
2 Reserved
3 Overload at the outputs
4 Incorrect operating mode selection
5 Internal error, system error
6 Overrange at the inputs
7 Overrange at the outputs
0 Reserved
Cause
In the temperature measure‐
ment operating mode, an in‐
put voltage is too high. The
hardware may become dam‐
aged/destroyed as a result.
Reserved
7.8 PP 72/48D PN and PP 72/48D 2/2A PN
Effect
The "PNFault" LED is activa‐
ted.
The outputs are switched off.
1)
The value 0x80 is stored in
status byte 1.
-
Connectable components
Remedy
It is essential that a Pt100 el‐
ement is connected to termi‐
nals 3-4 or 7-8.
The module must be restar‐
ted with Power ON following
elimination of the error.
-
225