Operation
External On / Off via Release input
32
Stepper motor-driven diaphragm dosing pump NXP-M and NXP-P
Operating instructions
11.2.2.2 Setting the transmission and reduction
The transmission and reduction factors can be set in 1% intervals of 1%
to 1000%. A set value of 100% means that the dosing pump executes
one dosing stroke per incoming pulse signal. For values above 100%, the
dosing pump executes more dosing strokes per pulse signal accordingly.
For values below 100%, the dosing pump executes less than one dosing
stroke per pulse signal, meaning that several pulse signals are required
before a dosing stroke is executed.
The number of pulse signals required for a dosing stroke is displayed on
the dosing pump display for values below 100%.
Int
Start
- +
50% (2)
Fig. 31: Number of pulse signals required (here: 2)
Examples for transmission / reduction
Number of pulses
Setting
Dosing strokes
4
25%
1
2
50%
1
1
100%
1
2
100%
2
4
125%
5
1
1000%
10
Table 27: Examples for transmission / reduction of pulse signals
In cases of sequences of sequential pulses, it must be noted that the
number of dosing strokes corresponding to the pulses does not always
follow the pulses immediately in certain settings. This is due to the fact
that only entire dosing strokes are executed, e.g. not half or quarter
dosing strokes. Depending on the transmission or reduction factor and
the number of pulses, however, there is a possibility of uneven results
with "pending" pulse signals. In theses cases, the required number of
dosing strokes is only achieved after a number of pulse cycles.
Examples:
The dosing pump receives pulses with a reduction factor of 30%. For the
first stroke, it requires 4 pulses in this setting (4 x 30% = 120%), as 3
pulses (3 x 30% = 90%) are insufficient for one dosing stroke (= 100%).
However, the second dosing stroke is executed after just 3 more pulses,
as the stroke buffer of the dosing pump still has 20% pending from the
first 4 pulses (120% - 100% = 20%) and this is added to the 3 pulses
(90% + 20% = 110%). The third dosing stroke also only requires 3
additional pulses (90% + 10% = 100%). A further 4 pulses are then
required for the fourth dosing stroke.
If pulses are transferred to the dosing pump with a transmission factor of
125%, a dosing stroke is executed for each of the first 3 pulses. With the
4th pulse, it executes 2 dosing strokes (3x 25% pending from the first 3
125% = 200%).
The dosing pump has a dynamic stroke buffer which includes the interval
between the pulses in the calculation and adjusts the distribution of the
dosing strokes accordingly.
11.2.2.3 Calculating the transmission factor
The dosing pump NXP-P has a defined stroke volume per dosing stroke. If
a certain dosing quantity is required per pulse, the corresponding
transmission factor can be calculated for the external operating mode.
11.2.2.4 Starting the dosing pump
Precondition for action:
ü
The dosing pump has been connected in accordance with the
chapter 9.2.2 “Connection socket 2“ on page 25.
1.
Press
Start
.
2.
Supply pulses to the pulse input of the dosing pump.
ü
Dosing pump has started.
11.2.2.5 Stopping the dosing pump
è
Stop the incoming pulses or press Stop.
ü
Dosing pump has stopped.
11.2.2.6 Operation with contact-type water meter
The dosing pump NXP-P is prepared for operation with a contact-type
water meter. The contact sequence of the water meter and the size of the
dosing pump must be matched to each other (calibrated).
11.3 External On / Off via Release input
11.3.1 NXP-M
The dosing pump NXP-M can be started or stopped via an open or closed
switching contact at the release input.
11.3.2 NXP-P
Regardless of the selected operating mode, you can start or stop the
dosing pump NXP-P by means of the closed switching contact on the
Release input.
Int
Start
- +
100%
Fig. 32: Start screen of external operation with symbol for closed contact in centre
For the significance of the menu symbols, see chapter 10.2.1 “Explana-
tion of the menu icons“ on page 27.
11.3.2.1 Starting the dosing pump
è
Close the switching contact on the Release input.
ü
Dosing pump has started.