ABB CI856 3BSE026055R1 DCS programmable communication unit
ErrorNo Error text in status field Description
1 INT/DINT overflow Signed integer or time operation caused overflow
2 INT/DINT underflow Signed integer or time operation caused underflow
3 INT/DINT div. by 0 Signed integer division by zero
4 UINT/DINT div. by 0 Unsigned integer division by 0
5 INT/DINT save overflow On storage, a signed 16-bit-integer operation
caused overflow
6 REAL overflow Real operation caused overflow
7 REAL underflow Real operation caused underflow
8 REAL div. by 0 Real division by zero
9 REAL invalid value Real operation with undefined value
10 DT overflow Operation with DT and TIME caused overflow
11 DT underflow Operation with DT and TIME or DT and DT caused
underflow
12 UINT/UDINT overflow Unsigned integer operation caused overflow
13 UINT/UDINT underflow Unsigned integer operation caused underflow
128 Program exec error An object not loaded (program, function block etc.)
is to be executed
129 FB error integer A function block from the function block library has
triggered an integer overflow or underflow, the error
can only be detected following execution of the
block and thus no recovery is possible.
130 FB error real A function block from the function block library has
triggered a REAL overflow or underflow, the error
can only be detected following execution of the
block and thus no recovery is possible.
131 Process image read error On reading the process image an unrecoverable
error has occurred
132 Process image write error On writing the process image an unrecoverable error has occurred.

4.4 Startup and Shutdown Performance of the Modules
A signal for connection monitoring is continuously exchanged between I/O modules and the
FieldController CPU of the process station or FieldController. If this signal does not appear for
more than 250 ms (for 500 kbit/s) and/or 1,25 s (for 100 kbit/s ) both sides detect the interruption
of the connection. The FieldController sends a system message to the operator station and the
output modules adopt the safety values. Dependent on the requests of the process the safety
values can configured as "Hold the last value" or to a particular value/state.
A cold process station or FieldController start always leads to output of the safety values.
For "Load whole station" and at resource Initialization/Overall reset, the output levels of the output
modules go to zero current.
4.5 Power fail signal (PF) and no power fail
PF < 15 ms While PF signal is active, the CPU module of the process station or the
FieldController does not communicate actual values; I/O modules maintain
the last values.
PF > 15 ms I/O modules maintain the last values until they have recognized the interrupted connection with the CPU module or FieldController; they then adopt
the configured safety values. Safety values are maintained until the CPU
module or FieldController has executed a warm start and sends new values
to the I/O modules.
4.6 Power fail signal (PF) and power fail
I/O modules maintain the last values until they have recognized the connection interruption and
then adopt safety values until the CPU module or FieldController sends actual values after restart.
In the case of power fail of the I/O module, output levels adopt zero voltage and/or zero current.
After voltage return I/O modules only change their output level when the CPU module or FieldController communicates actual values. Analog output modules are an exception. They hold the
last values as long as external voltage supply does not fail. Outputs are only deenergized if the
CPU module or FieldController is supplied with voltage.
4.7 Safety values for field devices
The cyclic exchange of data between Profibus master and the connected slaves is monitored.
When the cyclic exchange of data is interrupted, safety values can be assumed. The definition of
safety values for output channels is vendor-specific. For input channels, depending on the requirements of the process, the safety values can be configured to “Hold last value” or a specific
value or state.