UNIFREM v.3.41x
10 May 2017
Page 162 from 180
9 UNIFREM Frequency converter settings examples
9.1 Process controller - PC setting to control the level height in the tank
The following section will describe how to set the converter to maintain a constant level in the tank
using a pump controlled by frequency converter.
9.1.1 Situation
The frequency converter controls the speed of the pump, so that desired level of fluid in the tank is
maintained. The level in the tank can range from minimal 1cm to maximal 50cm. The actual height
level is sensed with level sensor with current output. Minimal level is at the value of the output 0mA
and maximal level is at the value of the output 20mA. The setpoint height level is adjusted by
voltage 0-10V. Minimal level corresponds to 0V and maximal level corresponds to 10V.
9.1.2 Converter connection
Connect the voltage for the setpoint level to the first analog input
AIN1.
Connect the sensor of level height to the second analog input
AIN2.
The output of the converter is connected to the pump.
9.1.3 Analog inputs setting
In the menu „SETTINGS / INPUTS AND OUTPUTS / ANALOG INPUTS“
„AIN1 –
AIN1 Type“ = „0
-
10V“
„AIN1 –
AIN1 Filter“ =
1ms (we can increase the filtration if the signal is distorted)
„AIN1 –
SPECIAL SETTING
–
AIN1 Signal“ = none (F3)
„AIN2 –
AIN2 Type“ = „0
-
20mA“
„AIN2 –
AIN2 Filter“ = 1ms (we can increase the filtration if the signal is distorted)
„AIN2 –
SPECIAL SETTING
–
AIN2 Signal“ = none (F3)
9.1.4 Process controller setting
In the menu „
SETTINGS
–
FUNCTIONS
–
PROCESS CONTROLLER.
“
„PC Mode“ = „Position“
Thus, the adjustment of process controller switches to the setting
in units of
cm.
Option „Position Inverse“ is used for the case, if the
pump is placed at the outlet of the tank and by increasing its
speed, the level will decrease at a constant inflow.
The other PC modes cause the switch setting in other units.
„Min. setpoint value“
= 1cm (minimal value of the process variable).
„Max. setpoint value“ = 50cm (maximal value of the process variable).
