DAB MCE-150/P, Instructions Manual

Page: 111 / 1024

ENGLISH
109
6.5.14 SO: Dry running factor
This sets the minimum dry running factor threshold below which the lack of water is detected. The dry running factor is a non-
dimensional parameter obtained by combining absorbed current and the pump power factor. Thanks to this parameter it is possible to
correctly establish when there is air in the impeller of a pump or if the suction flow is interrupted.
This parameter is used on all multi inverter systems and on all systems without flow sensor. If the pump functions only with one inverter
and flow sensor SO is blocked and disabled.
To help the user with the setting, the page shows the dry running factor measured in real time (in addition to the SO minimum dry
running factor to be set). The value measured is shown in a box below the name of the SO parameter and is called “SOm”.
In the multi inverter configuration, SO is a parameter which can be propagated between inverters but it is not a sensitive
parameter, i.e. it does not necessarily have to be the same for all inverters. When a change in SO is measured the user is asked
whether the value should be propagated to all the inverters.
6.5.15 MP: Minimum pressure pump stop due to water failure
This sets the minimum pressure pump stop due to water failure. If the system pressure reaches a pressure below MP the lack of water
is signalled.
This parameter is set on all systems without flow sensor. If the pump functions with flow sensor MP is blocked and disabled.
The MP default value is 0.0 bar and can be set up to 5.0 bar.
If MP=0 (default), the dry running is detected by the flow or the dry running factor SO algorithm;
if MP is not equal to 0, the lack of water is detected when the pressure is below the MP value.
The lack of water alarm is detected only when the pressure goes below the MP value for the amount of time set for the TB value, see
par. 6.6.1.
In the multi inverter configuration, MP is a sensitive parameter therefore it must always be the same along the chain of inverters in
communication and when the value is changed it is automatically propagated to all the inverters.
6.6 Technical Assistance Menu
From the main menu, press and hold “MODE” & “SET” & “+“ simultaneously until “TB” appears on display (or use the b or –
in the selection menu). This menu enables the display and modification of various configuration parameters. The MODE button enables
the user to scroll through the menu pages, while b and – enable respectively to increase and decrease the value of the
parameter concerned. To exit the current menu and return to the main menu, press SET.
6.6.1 TB: Water failure block time
Entry of a water failure block delay time enables selection of the time (in seconds) taken by the inverter to notify of low water levels on
the electric pump.
Modifications to this parameter may be useful if a known delay exists between the moment in which the pump is activated and the
actual moment of supply. One example is that of a system where the electric pump intake line is particularly long and is subject to
small leaks. In this case it may occur that the pipeline empties, and even if the water supply is regular, the electric pump takes some
time to reload, deliver flow and pressurise the system.
6.6.2 T1: Shutdown time after low pressure signal
This sets the inverter shutdown time starting from reception of the low pressure signal (see Impostazione della rilevazione di bassa
pressione par 6.6.13.5). The low pressure signal may be received on any of the 4 inputs, by suitably configuring the input (Setup degli
ingressi digitali ausiliari IN1, IN2, IN3, IN4 par 6.6.13).
T1 can be set between 0 and 12 s. The default setting is 2 s.
6.6.3 T2: Shutdown delay
This sets the delay after which the inverter shuts down after shutdown conditions have been reached: system pressure and flow at
minimum values.
T2 can be set between 5 and 120 s. The default setting is 10 s.