Liquid Dosing Control Manual
9.17.150 rev A – September 2020
Page
16
of
34
For example, when execute a batch with a flow rate of 100 g/h at an Full scale capacity of 100 g/h
is more accurate then at an Full Scale capacity of 1000 g/h.
To calculate the optimal Full Scale value in kg / h =
𝐵𝐵𝐵𝐵𝐵𝐵𝐵𝐵ℎ
𝐼𝐼𝑆𝑆𝑆𝑆𝑆𝑆
[
𝑔𝑔
]
𝐵𝐵𝐵𝐵𝐵𝐵𝐵𝐵ℎ
𝑑𝑑𝑀𝑀𝐼𝐼𝐵𝐵𝐵𝐵𝑆𝑆𝐹𝐹𝐼𝐼
[
𝐼𝐼
]
× 3.6
Changing the Full Scale value is explained in section 1.2.5 – Change the Capacity Value
When another Capacity Unit is used (section 1.2.4), then the Full Scale flow needs to be
calculated accordingly.
Tune the Batch Counter Controller
The Batch Counter value is used to control the actuator to achieve the desired Batch value.
By setting Counter Controller Overrun Correction to a value between 0 and 1, the system closes
the valve (or stops the pump) a fraction before reaching the batch size, minimizing overshoot.
- Write value <_> to parameter 274 – Counter Controller Overrun Correction
(Overrun Correction)
Value can be defined between 0 and 1. A typical value is 0.8.
A higher value corresponds with a faster correction and less learning cycles required, but
might also result in an unstable control behaviour.
A lower value corresponds with a slower correction and more learning cycles required.
The Counter Controller Gain will gradually close the valve or decrease the pump speed to ramp
down the flow speed until the batch size is reached. This will result in a more accurate batch.
The starting point of the ramp down is determined by the value of Counter control gain.
- Write value <_> to parameter 275 – Counter Controller Gain
(Point to ramp down)
Value can be defined as listed in the below overview.
If set to 0, the Control Gain is disabled and the system operates in ON/OFF control.
Step
DDE
ProPar Name
Data
type
Execute Value
Remark
1
274
104/10 Counter Controller
Overrun Correction
Float
Write
0.0…1.0 Overrun correction
Default = 0.8
2
275
104/11 Counter Controller
Gain
Float
Write
1…100
% of Batch size [point to ramp down]
