Calpeda I-MAT Serie Instrucciones De Uso página 34

9.2.2. Constant pressure mode with 2 pressure
transducers (differential mode)
If it is required to use a differential pressure
feedback, between delivery and suction of the pump
by using 2 transducers it's necessary to connect
the fi rst transducer and the second transducer as
GB
shown in section 6.7.
Set parameter AP02, to defi ne the supply of the
transducer, AP03 on 1 (bar) and the parameters
AP03 and AP05 to the right transducer full-scale.
Set parameter AP06, to defi ne the supply of the
transducer, AP07 on 1 (bar) and the parameters
AP08 and AP09 to the right transducer full-scale.
Set parameter AP10 on "DiFF" value.
To ensure the system works properly, the
primary transducer (B1-B4 clamps) must be
always connected to the delivery pipe, and
the secondary transducer (B5-B8 clamps)
must be always connected to the suction
pipe.
9.2.3. Minimum run frequency and pre-pause
frequency settings
The frequency converter is equipped with an
automatic stop system in case of low water. In
the case where the system does not guarantee
the correct stop of the pump, it is possible to set
manually the following values:
Frequency before stop
Minimum run frequency
In order to manually set these parameters it is
necessary to change the value of parameter AP17
from "Auto" to "Man". Then the pre-pause frequency
values (PC02 and PC04 parameters) and the
minimum frequency values (PC01 and PC03
parameters), must be set using the calculation
formulas described in the next section.
9.2.4. Frequency before stop and minimum run
frequency calculation formulas
Adjusting the pre-pause frequency (PC02 and
PC04 parameters) allows you to properly stop the
pump when the water demand is low and the pump
operation is no longer required (e.g. a leakage or a
small fl ow of a few liter per minute).
In this case the pump must be stopped for some
seconds and the fl ow is guaranteed by the reserve
stored in the vessel.
The frequency before stop Hz P can be calculated
as follows:
50 Hz pumps
Hz=2+ (√ Hset÷Hmax x 50) (*)
60 Hz pumps
Hz=2+ (√ Hset÷Hmax x 60) (*)
where: H set is the working pressure in bar,
H max is the maximum pump pressure, in bar,
when fl ow is equal to 0.
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(*) For the maximum pump pressure it's required:
For the pumps operating with suction lift subtract
the suction lift value (in bar).
For the pumps installed with suction positive add
the positive suction head value (in bar).
The minimum run frequency (PC01 and PC03
parameters) must be set 6-7 Hz lower than the
frequency before stop.
9.3. Proportional pressure mode
The proportional pressure operating mode reduce
the pressure proportionally with the water demand
of the system.
To enable this operating mode it is necessary to set
the parameter UP05 on "PP".
In this operating mode the frequency converter
keeps a set-point pressure at the maximum
frequency, this set-point pressure could be set with
the parameter UP06. The slope of the pressure-
fl ow rate line could be set through the percentage
of the pressure when fl ow is equal to 0 (parameter
PP01).
It is possible to have different confi gurations of this
operating mode related with the different types and
number of transducers installed:
Proportional pressure with 1 pressure transducer
(absolute or differential transducer).
Proportional pressure with 2 pressure transducers
in differential mode.
For detailed program settings see the following
confi guration sections.
9.3.1. Proportional pressure mode with single
transducer (differential or absolute)
This confi guration uses a feedback given by a
pressure transducer (connected as shown in
section 6.7). To allow this transducer properly work
it is necessary to set parameter AP02 (to defi ne
the supply of the transducer), parameter AP03 to
1 (bar) and the parameters AP03 and AP05 to the
right transducer full-scale (refer to the datasheet of
the transducer).
9.3.2. Proportional pressure mode with 2
pressure transducers (differential mode).
If it is required to use a differential pressure
feedback, between delivery and suction of the pump
by using 2 transducers it's necessary to connect
the fi rst transducer and the second transducer as
shown in section 6.7.
Set parameter AP02, to defi ne the supply of the
transducer, AP03 on 1 (bar) and the parameters
I-MAT_Ed1.indd - Operating Instructions