Features And Benefits; User Interface; Functions; Inputs And Outputs - Grundfos CUE Series Product Manual

Features and benefits

User interface

The user interface offers these possibilities:
• Local operation via a control panel with graphic dis-
play where the menu structure is based on the well-
known system from Grundfos E-pumps.
• Remote operation via external signals, for instance
via digital inputs or GENIbus.
• Monitoring of operating status via indicator lights
and signal relays.
• Display of alarm or warning and logging of the last
five alarms and warnings.

Functions

Control modes for centrifugal pumps
The CUE has a wide range of pump-specific functions:
• Open loop:
The speed is kept at a set value in the range of min.
and max. speed.
• Proportional differential pressure:
The differential pressure is reduced at a falling flow
rate and increased at a rising flow rate.
• Constant differential pressure:
The differential pressure is kept constant, independ-
ently of the flow rate.
• Constant pressure:
The pressure is kept constant, independently of the
flow rate.
• Constant level:
The liquid level is kept constant, independently of
the flow rate.
• Constant flow rate:
The flow rate is kept constant, independently of the
head.
• Constant temperature:
The liquid temperature is kept constant, independ-
ently of the flow rate.
• Constant other value:
Any other value is kept constant.
Start-up guide
The CUE has a start-up guide, which begins at the first
start-up. Here a number of parameters are set automat-
ically on basis of the pump type. Other parameters are
set manually on basis of the data on the motor and
pump nameplates.
Thanks to the start-up guide, the installer can quickly
set central parameters and put the CUE into operation.
Direction of rotation test
During the start-up guide, the CUE automatically tests
6
and sets the correct direction of rotation without chang-
ing the cable connections. This feature is activated only
if a pressure or flow sensor is installed.
Duty/standby
The duty/standby function is used to alternate between
two pumps. Each pump is connected to a CUE unit. The
primary task is to start the standby pump if the duty
pump is stopped due to an alarm and to alternate the
two pumps at least every 24 hours.
Duty/standby operation increases the security of supply
and ensures even use between the two pumps.
Dry-running protection
To protect the pump, select the dry-running function
together with an external sensor so that lack of inlet
pressure or water shortage can be detected.
Low-flow stop function
In control mode constant pressure or constant level, the
stop function is used for changing between on/off oper-
ation at low or no flow and continuous operation at high
flow rate.
The low-flow stop function protects the pump and saves
energy.
Monitoring of lubrication of motor bearings
When the bearing monitoring function is active, a warn-
ing will appear in the display when the motor bearings
are to be relubricated or replaced. Furthermore, the
function gives an estimated time to service.
This aids in motor maintenance programs.

Inputs and outputs

The CUE is equipped with a number of inputs and out-
puts:
• 1 analog input, 0-10 V, 4-20 mA
- external setpoint
• 1 analog input, 4-20 mA
- sensor input, feedback sensor
• 1 analog output, 0-20 mA
• 4 digital inputs
- start/stop and 3 programmable inputs
• 2 signal relays (C/NO/NC)
- programmable
• 1 RS-485 GENIbus connection.
Grundfos CUE