Flow Rate Controller
The flow rate controller is a two-channel controller that regulates the status of up to two components and the flow rate of one pump based on a flow rate sensor. The controller is mainly used as a controller for the fresh-water station.
The controller has 1 (plus 2 optional) analogic inputs.
The controller has 1 (plus 2 optional) outputs, partially digital, partially analogic.
Switch cut-in or off are based on the comparison of two different flow rates. The comparison may be made with a constant value or in respect of a variable flow rate of any component. Additionally a scaling factor referring to a flow rate setting may be output as an analogic signal.
Block Diagram
The block diagram shows the employed measuring and controlling values
Controller Input Mask “Fixed Value”
With this setting the hot water pump cuts in as soon as the flow rate of a tap is higher than 10 l/h. The tap flow rate will be referred to as the flow rate setting for the hot water pump.
Controller Input Mask “Variable Value”
With this setting the hot water pump cuts in as soon as the flow rate of the tap is higher than the flow rate of pipe 13. The tap flow rate will be referred to as the flow rate setting for the hot water pump.
Input Values
Flow Rate Sensor 1 [l/h]
The value refers to the point where the reference flow rate should be measured. Enter a component from the list. The value may be concurrently employed as output signal at the “Flow rate Pump 1” output. In this context the value is multiplied by the “Scaling factor“.
Flow Rate Sensor 2 [l/h]
An additional reference flow rate may be measured. Enter a component from the list. If 2 flow rate sensors are used their values are added. The added value may be concurrently employed as an output signal at the “Flow rate Pump 1” output. In this context the value is multiplied by the ”Scaling factor“.
Variable Flow Rate [l/h] (Optional)
The value refers to the flow rate setting to be measured. The value serves as the reference value for flow rate sensor 1 or 1 + 2.
Description of Control-Parameters
Description
The “description” value enables the user to assign controllers any name of number. Polysun assigns a consecutive number as a standard feature as different controllers are added chronologically in the hydraulic system
Sign of Output
The term “Normal“ means that digital output signals are controlled as intended in the switching logics. (Example: if X1>Fixed value or if X1>X2 the output of pump 1 is positive). The term “Inverted“ means that the digital output signals are multiplied by -1. (Example: if X1>X2 the output Switch 1 is equal to zero).
Definition of Flow Rate Setting
- Fixed value
If the flow rate measured on the flow rate sensor exceeds the specified Fixed value the controller switches to “on”. - Variable value
If the flow rate measured on the flow rate sensor exceeds the specified Variable value the controller switches to “on”.
Scaling Factor
The flow rate sensor value (X1+X2) is multiplied by the scaling factor and transferred via the “Flow rate Pump 1” as output signal to the relevant pump.
Output values
Status Pump 1
This digital output refers to the component to be controlled within the system. Select the relevant component from the list. (For the fresh-water station select the pump).
Status (Optional)
This digital output is activated just like the output of Status Pump 1. Select if required a component to be controlled from the list.
Flow Rate Pump 1 (Optional)
This option allows the pump to be speed-controlled. The flow rate setting is only active if the option “Flow rate setting” has been selected in the field “Flow rate controlled” for the pump to be controlled.
Overview of Control-Dependencies
Table: Control-dependencies of the flow rate controller
| Outputs | Parameter | Tip | Inputs | Function |
| Y1: Status Pump 1 Y1 = Y2 Y2: Status | Fixed value | Pump:enter in the field “Flow rate controlled“ the value “Flow rate setting” | X1: Flow rate sensor 1 X2: Flow rate sensor 2 | Y1=0 if X1 + X2 < Fixed value [l/h] Y1=1 if X1 + X2 > Fixed value [l/h] |
| Y3: Flow rate Pump 1 | Y3= (X1 + X2) * Scaling factor | |||
| Y1: Status Pump 1 Y1 = Y2 Y2: Status | Variable value | Pump:enter in the field “Flow rate controlled“ the value “Flow rate setting” | X1: Flow rate sensor 1 X2: Flow rate sensor 2 X3: Variable flow rate setting | Y1=0 if X1 + X2 < X3 Y1=1 if X1 + X2 > X3 |
| Y3: Flow rate Pump 1 | Y3= (X1 + X2) * Scaling factor |