Signal Outputs; Current Signal Control 0-20 Ma / 4-20 Ma - Grundfos DDI 222 Instrucciones De Instalación Y Funcionamiento

9.2.9 Flow Monitor
The pump can be equipped with a pressure sensor (Flow Monitor
pump option).
Based on the pressure measured by the sensor and on the motor
position, an indicator diagram is created. Possible dosing faults
or the exceeding of the permissible counter-pressure are
detected reliably and indicated by the display or the error
message output.
The following errors are recognised:
• Pressure exceeded (the pump is stopped and restarts
automatically when the pressure decreases).
• Dosing error (the pump doses 30 % to 100 % less due to a
leaking discharge valve or suction valve, a clogged suction
line or an air bubble in the dosing head).
Depending on the operating conditions, it may be
impossible to detect dosing errors due to several
Caution
faults occurring simultaneously (e.g. leaking suction
and discharge valves)!
The dosing controller and dosing control functions can be
switched on and off independently of each other. It is always
possibly to display the pressure that has been measured during
operation whenever the pressure sensor is connected.
For information about operating the pump with the
Note
Flow Monitor, see section

9.3 Signal outputs

The control unit has the following signal outputs, e.g. in order to
return a signal to the control room.
9.3.1 Current signal output
To use the control signal output, see section
Note

9.9 Current signal control 0-20 mA / 4-20 mA

The current flow rate of the pump is output as a current
signal.
• Current output 0-20 mA in the following mode:
– Current control 0-20 mA.
• Current output 4-20 mA in the following modes:
– Current control 4-20 mA
– Manual
– Contact
– Batch dosing with manual/contact start
– Timer with manual/contact start.
The current output is linear between 4 (0) mA at flow
rate = 0 and 20 mA at maximum flow rate Q
Note
(default setting) or the corresponding weighting value
pair.
9.3.2 Error signal
Used to return various error states to the control room.
9.3.3 Stroke signal / pre-empty signal / pulse input
Depending on the relay setting, the contact output receives a
signal in these cases:
• for each complete stroke of the pump, or
• a pre-empty signal input, or
• each pulse input at the pump.
To set the relay, see section 9.7.1 Modifying the switch
assignment .
9.10 Flow Monitor .
.
max.
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