Stop Function; Digital Input; Data Communication - Grundfos Hydro Multi-E Manual Del Usuario

10.3.5 Stop function

The purpose of the stop function is to stop the Hydro Multi-E at a
very low flow in order to avoid unnecessary power consumption.
The function is only active when one pump is operating.
The stop function can be set to these values:
• Active
• Not active.
Low flow is detected by means of the built-in "low-flow detector".
The Hydro Multi-E will check the flow regularly by reducing the
speed for a short time, thus checking the change in pressure.
If there is no or only a small change in pressure, this means that
there is low flow.
When the Hydro Multi-E detects a low flow, the speed will be
increased until the stop pressure (actual setpoint + 0.5 × ΔH) is
reached and the Hydro Multi-E will stop. When the pressure has
fallen to the start pressure (actual setpoint - 0.5 × ΔH), the Hydro
Multi-E will restart.
ΔH indicates the difference between start and stop pressures.
See fig. 27.
H
Stop pressure
ΔH
Start pressure
Fig. 27 Difference between start and stop pressures (ΔH)
ΔH is factory-set to 10 % of actual setpoint.
ΔH can be set within the range from 5 % to 30 % of actual
setpoint.
The stop function requires a tank precharge pressure of 0.7 ×
actual setpoint.
10.3.6 Sensor
The setting of the sensor is only relevant for
Note
normal operation.
Select among the following values:
• sensor output signal:
0-10 V
0-20 mA
4-20 mA
• unit of measurement of sensor:
bar, mbar, m, kPa, psi, ft, m
• sensor measuring range.
Q
3 3
/h, m /s, l/s, gpm, °C, °F, %

11. Digital input

The Hydro Multi-E has a digital input for external fault. The input
has been factory-set to external fault and will be active in closed
condition.
Functional diagram: input for digital function
Digital function
(terminals 1 and 9)
10 s
If the digital input is active for more than 10 seconds, the Hydro
Multi-E will stop because of an external fault.
The digital input is used for the dry-running protection.

12. Data communication

It is possible to connect the system to an external network.
The connection can be made via a GENIbus-based network or a
network based on another fieldbus protocol via a gateway.
The gateway may be a Grundfos CIU communication interface
unit or a third-party gateway. For further information on the CIU
units, see www.grundfos.com (WebCAPS) or contact Grundfos.
Normal duty
External fault
17