APPLICATION-SPECIFIC FUNCTION: PUMPS MANAGEMENT: (TANK MANAGEMENT WITH CIRCULAR PUMP CHANGEOVER)

This function is used to set to ON a maximum of four digital outputs which can be activated (OUTPUT 1 ... OUTPUT 4). This number is equal to the maximum number of digital inputs (from 2 to 4) in the ON state. In addition, the outputs set to ON are selected so that in the event of prolonged operation, each output will have been set to ON the same number of times.

The ON duration of the outputs is set to equal values by applying the following technique:

  • As the number of ON inputs increases, the outputs changing to ON are those following the order of the PILOT OUTPUT NUMBER: 1 for OUTPUT 1, 2 for OUTPUT 2, 3 for OUTPUT 3 and 4 for OUTPUT 4. For example, if the "outputs controlled" parameter has the value 4, if PILOT OUTPUT NUMBER has the value 3 and just one input is set to ON, only the OUTPUT 3 output will be set to ON. As soon as two inputs change to ON, the OUTPUT 3 output remains at ON and the OUTPUT 4 output changes to ON. As soon as a third input changes to ON, the OUTPUT 3 and OUTPUT 4 outputs remain ON and OUTPUT 1 changes to ON.
  • As soon as the number of outputs decreases, the outputs changing to OFF will be those which have been in the ON state the longest. As soon as one output changes to OFF, PILOT OUTPUT NUMBER takes the value of the output number after the output(s) which has (have) just been set to OFF. To complete the above example, as soon as one input changes to OFF, the OUTPUT 3 output changes to OFF and PILOT OUTPUT NUMBER displays the integer value 4.
  • The Parameters tab in the parameterisation box contains the number of outputs which may change to ON depending on the number of inputs which are set to ON. The values of this parameter are fixed at 2, 3 or 4.

    If the value of the parameter is fixed at 2, only the OUTPUT 1 and OUTPUT 2 outputs are used and may therefore change to ON. In this case, if more than two inputs change to ON, the OUTPUT 1 and OUTPUT 2 outputs remain at ON and the OUTPUT 3 and OUTPUT 4 outputs remain fixed at OFF.

    If the value of the parameter is fixed at 3, only the OUTPUT 1, OUTPUT 2 and OUTPUT 3 outputs are used and may therefore change to ON. . In this case, if four inputs change to ON, the OUTPUT 2, OUTPUT 2 and OUTPUT 3 outputs remain at ON and OUTPUT 4 remains fixed at OFF.

    If the value of the parameter is fixed at 4, only the OUTPUT 1, OUTPUT 2, OUTPUT 3 and OUTPUT 4 outputs are used and may therefore change to ON.

    All inputs which are not connected have the value OFF.

    When the program is initialised, PILOT OUTPUT NUMBER is fixed at 1.

    The Parameters tab contains the default check box which reinitialises PILOT OUTPUT NUMBER to 1 (and defines the first output activated when the first input changes to 1) after a controller power failure.

    Parameterisation box/Comments tab

    Example of use:

    Filling a tank with a group of four pumps operating in parallel. The operating duration of each pump is the same.

    The "number of outputs controlled" parameter is fixed at 4.

    On initialisation, PILOT OUTPUT NUMBER has the value 1. On initialisation, if the tank is in the state indicated and if a sensor above the water is in the ON state, when the user program is executed, the INPUT 1 and INPUT 2 inputs are ON, INPUT 3 and INPUT 4 are OFF and OUTPUT 1 and OUTPUT 2 are ON.

    Assuming that the tank is full, INPUT 2 changes to OFF and OUTPUT 1 changes to OFF. PILOT OUTPUT NUMBER indicates the value 2.

    Assuming that the tank is empty, INPUT 2 changes back to ON, OUTPUT 3 changes to ON and OUTPUT 2 remains ON.

    Assuming that the tank refills, INPUT 2 changes back to OFF, OUTPUT 2 changes to OFF and PILOT OUTPUT NUMBER indicates the value 3.

    Assuming that the tank continues to refill, INPUT 1 changes to OFF, OUTPUT 3 changes to OFF and PILOT OUTPUT NUMBER indicates the value 4.