62 Program features
• Fixed intervals (Fixed): The starting sequence is shifted periodically at pre-defined
intervals (parameter 78.05 Autochg interval). In traditional pump control, the pump
speed must also be below the level defined by parameter 78.04 Autochg level.
• Runtime equalization (Hourcount): The starting sequence is rearranged when the
difference between the runtimes of two pumps exceed a limit, 78.15 Runtime diff.
In the new sequence, the pump with the lowest runtime will be started first, the
pump with the highest runtime will be started last.
• Autochange when stopped (All stop): The starting sequence is shifted every time
the drive (in traditional pump control) or the master drive (in multipump or level
control) stops.
All pumps take part in the autochange sequence, except in a traditional pump control
configuration where a fixed pump is controlled by the drive at all times and the
remaining pumps are only turned on/off by the drive logic (an example is shown
starting on page 96). In this case, the fixed pump is always started first, and the
starting sequence of the auxiliary pumps is determined by the autochange function.
Settings
Parameter group 78 Pump autochange (page 257).
Diagnostics
Parameters 04.29…04.36 (pump runtime counters; page 124), 05.02 Trad pump cmd
(page 125), 05.03 Trad master (page 125), 05.04 Nbr aux pumps on (page 125),
05.36 First in order (page 126), 05.37 Time autochg (page 126), 06.20 Pump status
word (page 130), 08.21 Pump alarm word (page 134).
Flow calculation
The flow calculation function provides a reasonably accurate (typically ±3…6%)
calculation of the flow without the installation of a separate flow meter. The flow is
calculated on the basis of parameter data such as pump inlet and outlet diameters,
pressure at pump inlet and outlet, height difference of pressure sensors, and pump
characteristics.
The user can either define a PQ (power/flow) or HQ (head/flow) performance curve
that is used as the basis for the calculation. It is also possible to use both curve types
together with a breakpoint setting.
Notes:
• The flow calculation function is not to be used for invoicing purposes.
• The flow calculation function cannot be used outside the normal operating range
of the pump.
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