Limit Exceeded; Digital Inputs - Grundfos CUE Series Product Manual

Functions

Limit exceeded

Setting via PC Tool.
This is a monitoring function offering information, warn-
ing or alarm when a low or high limit is exceeded. See
fig. 35.
1 2 1
High limit
Hysteresis
Low limit
A
On
Off
Fig. 35 Example of low limit exceeded
Description
The function has two timers: a detection delay timer
and a reset delay timer.
The detection delay timer starts when a limit is
exceeded (1). See fig. 35. The time is configurable.
A: If the limit is no longer exceeded (2) when the detec-
tion time expires, the timer will be reset.
B: If the limit is still exceeded (3) when the detection
time expires, the output of the detector will change to
"limit exceeded".
The reset delay timer starts when the detector output is
"limit exceeded" and the limit is no longer exceeded,
using hysteresis (4).
C: When the delay time has expired (5), the detector
output changes to "limit not exceeded".
Input possibilities
It is possible to have two limit exceeded functions in
parallel with these inputs:
• all analog inputs
• all Pt100/Pt1000 inputs.
The use of Pt100/Pt100 inputs requires an MCB 114
sensor input module.
Output possibilities
There are these output possibilities:
• signal relay 1 and 2
• analog output
• warning and alarm.
3 4 5
B C
Limit exceeded
Temperature

Digital inputs

As standard, the CUE offers these digital inputs:
• one digital input for external start/stop
• three programmable digital inputs.
The three digital inputs can be set to these functions:
• min. (min. curve)
• max. (max. curve)
• external fault
• flow switch
• alarm reset
• dry-running protection (via external switch)
• accumulated flow (pulse flow, only DI 4)
• predefined ramps (setting via PC Tool)
• predefined setpoints (setting via PC Tool).
Start/stop
The pump will start if the pump is ready to run (the state
of the on/off button is on, and no alarms prevent the
pump from running.
Min.
The pump will run according to the min. curve.
Max.
The pump will run according to the max. curve.
External fault
If the input is activated for more than 5 seconds, exter-
nal fault will be indicated.
Flow switch
The flow switch indicates no flow in constant pressure
with stop function and constant level with stop function.
It requires an external signal from a flow switch or a
controller.
Alarm reset
When the input has been activated, the alarm will be
reset if the cause of the alarm no longer exists.
Dry running
Indicates lack of inlet pressure or water shortage, and
the pump will be stopped. The pump cannot restart as
long as the input is activated. Restart may be delayed
by up to 30 minutes, depending of the pump family.
For further information, see page 23.
Accumulated flow (only DI 4)
The number of pulses is counted and multiplied by the
litre/pulse parameter in order to get the accumulated
flow. This requires the use of an accessory, such as a
pulse sensor.
Grundfos CUE
27