Minimum Dosing Rate - Bayrol PoolManager Chlorine User Manual

12
Example 2 (chlorine, PoolManager

Setpoint 0.65 mg/l

Proportional range 0.50 mg/l

Dosing direction D+ (increase of chlorine value)
 The proportional range begins with the setpoint
(0.65mg/l, dosing rate 0 %)
 The proportional range ends 0.50 mg/l below the setpoint, i.e. at
0.15mg/l (dosing rate 100 %)
 The centre of the proportional range is at 0.40 mg/l
(dosing rate 50 %)
The following figure shows the correlation between the current
measured value and the dosing rate for various configurations of the
proportional range for pH (dosing direction D-).
1 Dosing rate in %
2 Measured pH value
3 Configured setpoint pH 7.20
4 Proportional range 0.50 pH (pH 7.20 - 7.70)
5 Proportional range 1.00 pH (pH 7.20 - 8.20)
6 Proportional range 2.00 pH (pH 7.20 - 9.20)
7 At the end of the proportional range, the dosing rate reaches
100%, i.e. the dosing pump runs permanently.
INFO
Basic rules for the proportional range
The following basic rules are helpful for the proportional
range:
A larger proportional range will result in a lower
dosing output.
For example, doubling the proportional range will halve
the dosing output.
A smaller proportional range will result in a higher
dosing output.
For example, halving the proportional range will double
the dosing output.
INFO
Pool volume and dosing rate
The default values for the proportional range are
orientated towards the following general conditions.

Assuming a pool volume of ca. 40 m³

dosing pump output ca. 1.5 l/h
30
PRO only):
®
For pool volumes that are larger in relation to the
dosing pump output, the proportional range
generally has to be reduced.
This leads to longer switch-on times on the dosing
pump, and therefore to higher dosage overall.
For smaller pool volumes in relation to the dosing
pump output, the proportional range generally has
to be increased.
This leads to shorter switch-on times on the dosing
pump, and therefore to lower dosage overall.
INFO
Influence on the control system
In the following cases, the proportional range should be
reduced, thereby increasing the dosing output:

If the control system reacts slowly, and the setpoint
is not approached or is only approached slowly
In the following cases, the proportional range should be
increased, thereby decreasing the dosing output:

If the control system reacts too quickly or unstably
12.4.5

Minimum dosing rate

A purely proportional control system generally has problems in actually
reaching the desired setpoint. When approaching the setpoint, the
dosing rate drops continuously and approaches 0 %.
In order to guarantee the setpoint is reached, a minimum dosing rate
is configured that is maintained until the setpoint is actually reached.
The following figure uses the pH control system as an example to
show the progress of the actual dosing rate with a minimum dosing
rate of 5%.
1 dosing rate in %
2 Measured pH value
3 Configured setpoint pH 7.20
4 Configured minimum dosing rate (5 %)
5 Constant dosing at the minimum dosing rate
upon approaching the setpoint
6 Theoretical progress without a minimum dosing rate
INFO
Dosing when near the setpoint
The dosing rate when near the setpoint, i.e. for small
control deviations, is determined by the configured
minimum dosing rate only. The proportional range has
no influence when near the setpoint.