Grundfos CRE Series Installation And Operating Instructions Manual page 26

Digital input/output 3 and 4, Function
The digital input/output 3 and 4 can be set to these functions:
Possible functions, digital input/output 3
Set to digital input
• Not active
• Predef. setp., dig2
• External fault
• Alarm resetting
• External stop
• Max.
• Min.
• Flow switch
• Dry running
• Accumulated flow
Possible functions, digital input/output 4
Set to digital input
• Not active
• Predef. setp., dig3
• External fault
• Alarm resetting
• Reversing
• External stop
• Max.
• Min.
• Flow switch
• Dry running
• Accumulated flow
The number of available displays depends on the pump type. See
below.
Function (terminal)
Digital input/output 3, Function
(10 and 6)
Digital input/output 4, Function
(11 and 18)
26
Set to digital output
• Ready
• Operation
• Alarm
• Warning
• Limit 2 exceeded
• Limit 1 exceeded
• Running
• Not active
Set to digital output
• Ready
• Operation
• Alarm
• Warning
• Limit 2 exceeded
• Limit 1 exceeded
• Running
• Not active
CRE, CRIE,
CME CRNE, CRKE,
SPKE, MTRE
● ●
- ●
Low-flow stop function
The low-flow stop function can be set to these values:
• Not active
• Energy optimal
• High comfort
• User-defined.
When the low-flow stop function is active, the flow will be
monitored. If the flow becomes lower than the set minimum flow
(Q ), the pump will change from continuous operation at
min
constant pressure to start/stop operation and finally be stopped if
the flow reaches zero.
The advantages of enabling the low-flow stop function are the
following:
• no unnecessary heating of the pumped liquid
• reduced wear of the shaft seals
• reduced noise from operation.
The disadvantages of enabling the low-flow stop function may be
the following:
• The delivered pressure is not completely constant as it will
fluctuate between the start and stop pressures.
• The frequent starts/stops of the pump may in some
applications cause acoustic noise.
The impact of the above disadvantages very much depends on
the setting selected for the low-flow stop function.
The "High comfort" setting will minimize pressure fluctuations and
acoustic noise.
If "Energy optimal" is selected, the main priority will be to reduce
the energy consumption as much as possible.
Possible settings of the low-flow stop function:
• Energy optimal:
The pump will automatically adjust the parameters for the stop
function so that the energy consumption during the start/stop
operation period is minimized.
In this case, the stop function will use factory-set values of
minimum flow (Q ) and other internal parameters.
min
• High comfort:
The pump will automatically adjust the parameters for the stop
function so that the disturbances during the start/stop
operation period are minimized.
In this case, the stop function will use factory-set values of
minimum flow (Q ) and other internal parameters.
min
• User-defined:
The pump will use the parameters set for ∆H and Q
respectively for the stop function.
min