Operators Handbook DCU3 – System
6., Main function „Control Loops“
BAEDCU3 - Rev. 4.6 - 0504 6 - 31
6.20 Gravimetric Dosing Controller
The „Flow controller“ is a precise gravimetric dosing controller. It will be used together with a balance
system. Balance systems suited and tested for the DCU - system are the MC1-type balance by Sarto-
rius, Fed. Rep. of Germany, or Mettler Balances type AM/PM/SM, offering a RS232-type interface.
The storage vessel will be placed on a balance system, which is connected to the DCU - system via
the serial interface. The flow controller controls a peristaltic pump (any commercially available pump
for continuous control) to supply substrate from the storage vessel into the culture vessel. The DCU -
system calculates the delivered volume considering the weight change. It can ensure a constant flow
by continuous control of the external pump.
This control function directly acts upon the input weight signal delivered from the balance system.
Therefore the gravimetric dosing controller provides a precise dosing for days and weeks.
6.20.1 Operating Display
For a description of the tags, the physical units or entries, the displayed value or function
and of the required inputs see the table in section 6.3, Controller Operation in General.
6.20.2 Operating Information
To operate the substrate supply with the flow controller proceed as follows:
1. Fill storage vessel, sterilize, if necessary, and place onto balance platform
2. Adjust the zero point of the balance
3. Adjust the setpoint for the flow controller in the DCU - system
4. Switch operating mode of the flow controller to „auto“
Check display of the weight, a negative value indicates the delivered volume (weight)
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