Pentax IPFC 109 Manual Del Usuario página 16

5.2 IPFC installation for differential constant pressure applications
IPFC can manage the pump speed in order to keep constant the pressure difference between the dischage and suction side of
the pump in circulation systems. To do this, it is usually installed a differential pressure sensor. Alternatively, it is possible to
use two identical pressure sensors: one in suction side and one in discharge side of the pump. The difference of values is
performed by the IPFC itself.
N.B. If during the operation it is expected that the pressure in the suction side falls below the atmospheric pressure, it is
necessary to use absolute pressure sensors and not relative ones.
5.2.1 Sensors wiring
The IPFC can be connected to linear pressure sensors with 4 - 20 mA output. The supply voltage range of the sensors must
include the 15 VDC with which the IPFC feeds the analog inputs.
If you are using a differential pressure sensor it is necessary to connect the sensor to the analog input 1:
DIFFERENTIAL SENSOR
In case two pressure sensors are used, the pressure sensor in the discharge side must be connected to the analog input 1
while the pressure sensor in the suction side must be connected to the analog input 2:
SENSOR 1 (discharge)
SENSOR 2 (suction)
In the IN/OUT parameters menu it is therefore necessary to set the logic AN1, AN2 as "difference".
5.2.2 Programming
In circulation systems pump starting and stopping is usually controlled by an external contact that can be connected to the
digital input 1 (IN1, 0V) and configured as N.O or N.C in the IN/OUT parameters menu. It is then recommended to set the
following parameters:
Control parameter Recommended value
Freq. min control Same as minimum motor frequency
Delta control 0 bar
Delta start 0 bar
Stop delay 99 sec
IN/OUT parameter Recommended value
Function AN1,AN2 Difference 1-2
Constant differential pressure
The "set value" corresponds to the differential pressure to be kept constant.
Set the "set value" equal to the pressure difference measured between the discharge and the suction side of the pump at
maximum load (all utilities opened) and at maximum frequency (50 Hz).
Proportional differential pressure
In case it is needed to use a control logic based on proportional differential pressure (in order to achieve a further energy
saving), it is necessary to set the "set value" equal to the pressure difference between the discharge and suction side of the
pump at minimum frequency (20 Hz ) and "compensation" in order to reach the maximum set value at maximum frequency
(50 Hz) and maximum load (all utilities opened).
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 AN1: 4-20 mA (-) signal
 +15V: 15 Vdc (+) supply
 AN1: 4-20 mA (-) signal
 +15V: 15 Vdc (+) supply
 AN2: 4-20 mA (-) signal
 +15V: 15 Vdc (+) supply