23
NRR 2-50, NRR 2-51 - USA - Installation & Operating Manual -
850699-00
In the control cabinet: Electrically connecting the level controller
Supply voltage connection
The equipment is supplied with 24 V DC and has an external 0.5A medium time-lag fuse.
Please use a safety power supply unit with protective electrical isolation (PELV / CLASS2).
This power supply unit must provide a level of isolation against dangerous contact voltages that
at least meets the requirements for double or reinforced insulation in accordance with the follow-
ing standard: UL 60730-1.
Connecting the level transmitter
Please use a shielded, multi-core TC-ER control cable with minimum wire size AWG18, e.g.,
OELFLEX CONTROL TM CY 5G1, to connect the equipment. Max. length 328 ft (100 m).
Max. 3 NRS/NRR 2-5.. switches/controllers can be connected to one level transmitter.
Connect the terminal strip as shown in the wiring diagram.
Fig. 6, 7
Connect the shield as shown in the wiring diagram.
Route the connecting cable between items of equipment separately from power lines.
Connecting the output contacts
Connect the upper terminal strip
1
(terminals 16-23) according to the desired switching
functions.
Provide an external 2.5A slow-blow fuse for the output contacts.
When inductive loads are switched off, voltage spikes are produced that may have a major ad-
verse effect on the operation of control and measuring systems. Connected inductive loads must
therefore have interference suppression (RC combination) as specified by the manufacturer.
Attention
■
Do not use unused terminals as support terminals.
Output of manipulated variable Y or connection of actual value output (optional)
Please use a shielded, multi-core control cable with minimum wire size AWG20, (0.5 mm
2
), e.g.,
OELFLEX CONTROL TM CY 3G1, for connection. Max. length 328 ft (100 m).
Please note the maximum output load of 500 ohms (output of manipulated variable Y).
Connect the terminal strip as shown in the wiring diagram.
Fig. 6, 7
Connect the shield
just
once
to the central grounding point (CGP) in the control cabinet.
Route the connecting cable between items of equipment separately from power lines.
Any item of equipment that you wish to connect to the terminals for the output of manipulated
variable Y or actual value output 4-20 mA (optional) must be certified to have at least double or
reinforced insulation according to UL 60730-1 between the current loop and live parts of the
equipment that are not supplied with safety extra-low voltage (SELV).
