Operating Range; Limit-Exceeded Function - Grundfos Hydro Multi-E Series Installation And Operating Instructions Manual

12.7

Operating range

Set the operating range as follows:
• Set the minimum speed within the range of fixed minimum
speed to user-set maximum speed.
• Set the maximum speed within the range of user-set minimum
speed to fixed maximum speed.
The range between the user-set minimum and maximum speeds
is the operating range. See fig. 35.
100 %
Fixed maximum speed
67 % User-set maximum speed
Operating range
User-set minimum speed
24 %
13 %
Fixed minimum speed
0 %
Fig. 35 Example of minimum and maximum settings
Factory setting
See section 29. Factory settings.

12.8 Limit-exceeded function

This function can monitor a measured parameter or one of the
internal values such as speed, motor load or motor current. If a
set limit is reached, a selected action can take place. You can set
two limit-exceeded functions, meaning that you can monitor two
parameters or two limits of the same parameter simultaneously.
The function requires determining the following settings:
"Measured"
This menu/display/function allows you to set the measured
parameter for monitoring.
"Limit"
This menu/display/function allows you to set the limit which
triggers the function.
"Hysteresis band"
This menu/display/function allows you to set the hysteresis band.
"Limit exceeded when"
This menu/display/function allows you to select whether the
function is activated if the selected parameter exceeds or drops
below the set limit.
• Above limit.
The function is activated if the measured parameter exceeds
the set limit.
• Below limit.
The function is activated if the measured parameter drops
below the set limit.
Note: The "Limit exceeded" function with the "Below limit" setting
is the factory standard for dry-run protection on Hydro Multi-E
pump systems.
"Action"
If the value exceeds a limit, you can set an action. You can select
the following actions:
• No action
The pump remains in its current state. Use this setting if you
only want to have a relay output when the limit is reached. See
section 13.5 Signal relays 1 and 2 ("Relay
• "Warning/alarm"
A warning is given.
• "Stop"
The pump stops.
• "Min."
The pump reduces speed to minimum.
• "Max."
The pump increases speed to maximum.
• "User-defined speed"
The pumps runs at a speed set by the user.
Detection delay
You can set a detection delay which ensures that the monitored
parameter stays above or below a set limit in a set time before the
function is activated.
Resetting delay
The resetting delay is the time elapsed from the measured
parameter differing from the set limit, including the set hysteresis
band, until the function is reset.
Example:
The function monitors the outlet pressure from a CRE pump. If
the pressure is below 72.5 psi (5 bar) for more than 5 seconds, a
warning must be given. If the outlet pressure is above 102 psi (7
bar) for more than 8 seconds, reset the limit exceeded warning.
1
2
4 4
A
5
Fig. 36 Limit exceeded (example)
Pos. Setting parameter
1 "Measured"
2 "Limit"
3 "Hysteresis band"
4 "Limit exceeded when"
5 "Detection delay"
6 "Resetting delay"
A "Limit exceeded function active"
- "Action"
Factory setting
See section 29. Factory settings.
outputs").
3
Time [s]
6
Setting
Outlet pressure
73 psi (5 bar)
29 psi (2 bar)
Below limit
5 seconds
8 seconds
-
Warning
21