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Rev. May 2001 GraviMaster-FGB-M05 (S) Page 8
Gravimetric Blender
2.6 Dispense modes
The blender has two ways of dispensing: gravimetric and volumetric. One mode can be
selected or a combination of both. This can be defi ned choosing menu (F1) ‘controller /
public parameters’.
Gravimetric
All component of the batch are dispensed and measured separately. Gravimetric is more
accurate than volumetric, but takes more production time, ie., lower output.
Volumetric
All components of the batch are dispensed at the same time using the dispense time of each
component (calculated by the system). The components are dumped directly in the mixer
chamber. No measurement is done in this mode. Therefore this method is less accurate, but
the production time is faster, ie., maximum output
Combination
When combination is defi ned, one gravimetric will be followed by a defi ned number of
volumetric dispenses. This is defi ned by the parameter combinationRatio. This parameter can
only be defi ned if ‘combination’ is chosen. This mode has the best of gravimetric and
volumetric.
Use: normally the defi ned combination will be done (ex. 1:3). However, if the mixer chamber
is full, the process will automatically do a gravimetric dispense instead of a (possible)
volumetric one.
2.7 Batch handling
2.7.1 Production control
If a start command is given the controller will check if the blender actually can start. If a
hopper has a low-indication (optional) the controller will alarm.
Also the parameters are checked. These can be in confl ict with the recipe to be executed.
The following items will be checked (if applicable):
* Empty Regrind control
- The controlled hopper must contain regrind (according to recipe)
* Stock silo control (optional)
- Controlled hopper must contain regrind (according to recipe)
* Additive to regrind
- Controlled hopper must contain additive (according to recipe)
The blender will not start unless all conditions are met. A message will be sent to the user interface.