Grundfos CU 301 Manuel D'instructions page 19

Relation to other displays
The maximum speed setting can be read in display
5.3.6 Maximum speed.
The maximum pump speed setting overrules the cut-
in speed setting.
5.3.8 Buttons on the CU 301
The buttons on the CU 301 can be set to:
• Active
• Not active.
5.3.9 Indication of pump operation
The following settings are available:
• Running light
• Constant light.
5.3.10 Number
Allocate a number to the CU 301 and the pump con-
nected. The CU 301 and the pump must have the
same number.
The CU 301 control unit communicates with the SQE
pumps via the pump power cable to turn the pumps
on and off, set motor speed and monitor pump sta-
tus.
The technique used for performing this communica-
tion impresses a high frequency data signal on the
pump power cable that is picked off by internal pump
electronics and then decoded into command instruc-
tions. This is the reason for assigning unique num-
bers to each CU 301 in a multiple unit installation.
The unique number serves as a communication
address between each CU 301 control unit/motor
pair.
In situations where multiple CU 301 pump power
cables are run parallel in wiring trays or conduit and
less than 10-12 inches apart, the possibility for
undesired communication between units exists.
When this occurs, intermittent or continuous "No
contact" is typically seen. Other unexpected errors
may also be seen.
There are two approaches available to eliminating
the possibility of this occurring:
• Physical separation of cables:
Maintain a minimum distance of 10-12 inches
between pump power cables, and never place
more than one cable in a conduit.
• Use shielded cable:
The use of shielded cable prevents cross commu-
nication between parallel cables and allows shar-
ing of conduit and cable trays. Tie the cable shield
to earth only at the CU 301 control unit.
Suitable cables:
Manf. Part#
Anixter 2A-1403S
Anixter 2A-1203S
Anixter 2A-1003S
Anixter (1-800-321-1486)
In addition, Grundfos recommends applying power to
only one CU 301 unit/motor at a time while program-
ming the CU 301 number with the R100. This will
prevent the possibility of two pumps hearing the
same number assignment command.
Gage
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12
10
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