Liquid Dosing Control Manual
9.17.150 rev A – September 2020
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9
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2.2.5 Change Flow Settings – Capacity Value
The instrument has a set minimum and maximum Full Scale capacity, which are the operating
limits of the instrument as set by Bronkhorst according to the specification sheet.
The Capacity Value can be changed between these minimum and maximum values.
Situations where changing the Capacity Value can benefit the dosing application:
- An oversized instrument is selected because of a larger sensor tube diameter (lower
pressure drop). The Capacity Value can be adjusted to match the application.
Example: An instrument with a maximum flowrate of 30 kg / h is used for an application
operating at a maximum of 10 kg / h, resulting in a flow measurement of 33.3%.
Lowering the Capacity Value to 10 kg / h to match the application will result in a
flow measurement of 100%, which can be beneficial for monitoring and logging
purposes.
- The setup is used for flows in both the lower range and higer range of the instrument.
Changing the capacity value to match the desired flow rate can increase the resolution of the
measurement data.
- The Bronkhorst instrument sends an Analog signal to another instrument. The resolution of
the analog signal improves when the Capacity Unit is in the same range as the process flow.
Please note that by changing the Capacity Unit, the analog out signal can change as well,
and the receiving instrument might need to be adjusted
- A Ratio control setup where the setpoint (Slave Factor) is calculated using the Capacity
Value (100% point) of the instrument. Adjusting this value can help to determine the ratio
control setpoint.
Disable protected mode
- Write value 64 to parameter 7 – Init Reset
(unlock secured parameters)
Change Capacity Value
- Write value
<flow>
to parameter 21 – Capacity
(Full Scale capacity value)
Use the same flow measurement unit as configured in the Capacity Unit section
Enable protected mode
- Write value 82 to parameter 7 – Init Reset
(lock secured parameters)
Step DDE ProPar Name
Data
Type Execute Value
Remark
Unlock Secured Parameters
1
7
0/10
Init Reset
Uint8 write
64
Unlock secured parameters
Volume Flow
2
21
1/13
Capacity
Float write
<capacity> Full Scale Capacity in Capacity Unit
Lock Secured Parameters
3
7
0/10
Init Reset
Uint8 write
82
Lock secured parameters
