Operators Handbook DCU3 – System
2., Operating Behaviour
BAEDCU3 - Rev. 4.6 - 0504 2 - 1
2 OPERATING BEHAVIOUR
The DCU3 - system stores all parameters which are adjustable by the operator (setpoint, calibration
parameters, profiles, etc.) in a battery buffered memory. Hence these parameters are still available
when the DCU3 system is switched off and restarted again.
For enabling the outputs of the DCU3 - system and of several system functions, which directly act on
the fermentor system, 4 categories of switching-off or power failure, respectively, are differentiated:
1. Switching „off“ and „on“ using the mains switch at the front panel (see pos. 3 in fig. 1-1).
2. Shut down due to mains failure.
3. Emergency cut-off via the „SHUT-DOWN“-key at the operating terminal or using the mains
switch of the supply unit or cabinet of the fermentor (see BIOSTAT® MD, ED or BIOSTAT®
C-DCU3, UD, for instance).
4. Interlocking functions for system outputs.
2.1 Switching „off“ and „on“
The DCU3 - system is switched-on or off, respectively, via the mains switch on the front panel. After
being switched-on (again) the DCU3 will start at (return to) a defined state of operation:
All controllers are „off“, actuators are in rest position
All timers are „off“ (stopped)
No recipe loaded, no program (sterilization for example) active
2.2 Mains Failure
In the case of a (mains) power failure, after being restarted, the DCU3 - system continues its activities
as follows:
Controllers run on with the setpoint, which has been adjusted at the time of the power failure
Timers and setpoint profiles will be continued
Sequences, such as sterilization programs, and recipes will be continued
The operator can set a maximum power failure time (FAILTIME) in the „maintenance“ menu. This is a
specific feature of the DCU3 - system. When the power failure lasts longer than the preset FAILTIME,
then the DCU3 - system behaves as if being switched-off with the mains switch, i.e. the system will be
shut down and set to a defined basic state.
After a power failure the system generates the message „Power Failure“, together with the time and
duration of the failure. If the maximum power failure time has expired (see „FAILTIME“), the system
displays the message „Pwf stop ferm“ with time and duration of the failure. See also the description of
the „Alarm messages“ in the supplement.