GESTRA NRS 2-4 User manual

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EN
English
Level Switch
NRS 2-4
Original Installation Instructions
810427-03

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Contents
Usage for the intended purpose .............................................................................................................4
Safety note .............................................................................................................................................4
Danger ...................................................................................................................................................4
Attention.................................................................................................................................................4
LV (Low Voltage) Directive and EMC (Electromagnetic Compatibility) .......................................................4
ATEX (Atmosphère Explosible).................................................................................................................4
Important Notes
Page
Explanatory Notes
Scope of supply ......................................................................................................................................5
Description .............................................................................................................................................5
Function .................................................................................................................................................5
Design....................................................................................................................................................5
NRS 2-4c................................................................................................................................................ 9
NRS 2-4d................................................................................................................................................9
Tools.......................................................................................................................................................9
Installation
Electrical Connection
NRS 2-4................................................................................................................................................10
Wiring diagram .....................................................................................................................................10
Key.......................................................................................................................................................11
Attention...............................................................................................................................................11
Note .....................................................................................................................................................11
Tools.....................................................................................................................................................11
NRS 2-4..................................................................................................................................................6
Dimensions.............................................................................................................................................7
Technical Data
NRS 2-4..................................................................................................................................................8
Key.........................................................................................................................................................8
Functional Elements

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Contents – continued –
Page
Commissioning Procedure
Checking electrical connection .............................................................................................................12
Applying mains voltage.........................................................................................................................12
Danger .................................................................................................................................................12
Performance test ..................................................................................................................................12
Table 1 .................................................................................................................................................12
Operational Malfunctions
Danger .................................................................................................................................................13
Fault finding list for troubleshooting......................................................................................................13
Annex
Note on the Declaration of Conformity / Declaration by the Manufacturer CE.........................................14

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Important Notes
Danger
The terminal strip of the NRS 2-4 is live during operation.
This presents the danger of electric shock!
Cut off power supply before inserting or removing the 19" slide-in unit and before carrying
out any installation or maintenance work.
Usage for the intended purpose
The level switch NRS 2-4 is used in conjunction with level electrode NRG 211 and signals a maximum
admissible liquid level.
Safety note
The level switch is a safety device and must only be installed, wired and commissioned by qualified and
competent staff.
Retrofitting and maintenance work must only be performed by qualified staff who – through adequate
training – have achieved a recognised level of competence.
Attention
The name plate specifies the technical features of the equipment. Note that any piece of
equipment without its specific name plate must neither be commissioned nor operated.
LV (Low Voltage) Directive and EMC (Electromagnetic Compatibility)
The level switch NRS 2-4 meets the requirements of the Low Voltage Directive 2014/35/EC and the
EMC Directive 2014/30/EC.
ATEX (Atmosphère Explosible)
According to the European Directive 2014/34/EC the level switch NRS 2-4 must not be used in
potentially explosive areas.

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Description
The level switch NRS 2-4 is an analogue electronic amplifier for the capacitance electrode NRG 211.
In conjunction with the electrode NRG 211 it can detect high water level.
In addition, the level switch detects possible malfunction signals coming from the electrode and
monitors the electrode supply cable.
Design
NRS 2-4c:
19 slide-in unit with guide rails and 32 pole screw-type connector for installation in 19 magazine to DIN
41494, part 5. Front panel to DIN 41494, part 5, 6 division units*).
NRS 2-4d:
Spare 19 slide-in unit, front panel to DIN 41494, part 5, 6 division units.
Function
The NRS 2-4 is a single-channel device equipped with a power supply unit and a voltage detector. The
feed voltage (12 V DC) for the electrode is – depending on the operating condition – converted into a
measuring voltage. The signal decoder allocates the measuring voltage to an operating condition which
is indicated by the LEDs on the front panel of the NRS 2-4.
The level switch can signal the following four operating conditions:
nNormal operation
nHigh level alarm
nMalfunction in level electrode
nMalfunction in connecting cable
In the event of a high level alarm or malfunction the corresponding output relay will be triggered.
In addition to the output relays optocouplers are also available for switching.
Explanatory Notes
Scope of supply
NRS 2-4c
1 Level switch designed as 19" slide-in unit, front panel to DIN 41494, part 5, 6 division units*)
2 Guide rails
1 Screw-type connector
1 Installation manual
NRS 2-4d
1 Level switch designed as 19 slide-in unit, front panel to DIN 41494, part 5, 6 division units*)
1 Installation manual
*) 1 division unit = 5.08 mm

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NRS 2-4
Input measuring circuit
1 V to 10 V DC (measuring voltage coming from level electrode)
Output measuring circuit
12 V DC (supply voltage for level electrode)
Output
2 volt-free relay contacts. Max. contact rating with switching voltages of
24 V, 115 V and 230 V AC: resistive 4 A, inductive 0.75 A at cos j0.5.
Max. contact rating with switching voltage 24 V DC: 4 A. Contact material silver, hard gold plated.
2 optocouplers (NPN), short-circuit protected due to current limiting, max. 70 V, 10 mA
Indicators and adjustors
1 LED for “Alarm”, 2 LEDs for “Malfunction”, 1 LED for “Power”
Mains voltage
18 - 36 V DC
Power consumption
2 VA
Housing material
NRS 2-4c: Front panel: aluminium
NRS 2-4d: Front panel: aluminium
Weight
NRS 2-4c/d: aprox. 0.6 kg
Technical Data

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Fig. 1
Technical Data – continued –
Dimensions
169
128.5
30.48
(6 division
units)

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Functional Elements
NRS 2-4
Fig. 2
A
C
B
E
DF
A32-pole screw-type connector, DIN 41612, design D
BLED “Power”
CLED “Malfunction in connecting line”
CLED “Malfunction in level electrode”
ELED “High level alarm”
FFixing screws
Key

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Installation
NRS 2-4 c
1. Mount plastic guide rails in 19 magazine.
2. Install screw-type connector.
3. Insert level switch in 19 magazine and fix it with screws F.
Tools
nScrewdriver 5.5/100
NRS 2-4 d
1. Insert level switch in 19 magazine and fix it with screws F.

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Electrical Connection
NRS 2-4
Note that screened four-core cable, e. g. I-Y(St)Y 2 x 2 x 0.8 or LIYCY 4 x 0.52 is required for wiring.
Max. length: 500 m.
Wire screw-type connector according to the wiring diagram. Fig. 3
Wiring diagram
Fig. 3
32
1
NRG 211
C28
A30
A24
A28
C30
C24
DC
DC
24V DC
12V DC
M
C16
C18
A18
NRS 2-4
A22
A20
C 8
A 2
C 12
C 4
A 10
A 6
C22
C20
MAX
2
3
4
5
6
1
32
1
12V DC 12V DC
MM
C16
C16
C18
C18
A18
A18
NRG 211
NRS 2-4 NRS 2-4
7
1
7
1
2
3
4
5
6
1

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n To protect the switching contacts fuse circuit with 2.5 A (slow-blow) or according to
TRD regulations (1.0 A for 72 h operation).
nThe screen must not make any other electrical contact
Attention
Electrical Connection – continued –
1 Level electrode NRG 211
2 Test loop for equipment
3 Switching output for “Alarm” (optocoupler)
4 Switching output for “Malfunction” (optocoupler)
5 Switching output for “Alarm” (relay)
6 Switching output for “Malfunction” (relay)
7 Wiring diagram for two high-level switches installed in parallel (redundancy)
Key
Note
nConnect screen only to terminal A18 of the level switch.
nThe monitoring of the level electrode and the connecting lines can be included in the
safety circuit. For this purpose the safety circuit must also be fed to the relay output
“Malfunction”.
nThe rated voltage is indicated on the name plate.
nWhen switching off inductive loads, voltage spikes are produced that may impair the
operation of control and measuring systems. Inductive loads should be provided with
commercial arc suppressor RC combinations, e. g. 0.1 μF/100 Ω.
Tools
nScrewdriver for slotted screws, size 2.5, completely insulated according to VDE 0680

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Apply mains voltage. The green LED Bis illuminated. Fig. 2
Commissioning Procedure
Make sure that the NRS 2-4 and the associated level electrode NRG 211 are wired in accordance with
the wiring diagram. Fig. 3
Checking electrical connection
Applying mains voltage
NRS 2-4 c/d
1. When switching on the mains voltage the green LED Bmust be permanently illuminated. Fig. 2
2. Raise water level until it exceeds the high level mark.
The red LED Eof the level switch must light up.
3. Lower water level until it falls below the high level mark. The red LED must go out.
4. After detaching the connector from the level electrode the amber LED Cmust light up (malfunction
in connecting line).
5. After bridging the terminals C16 and C18 the amber LED Dmust light up (malfunction in equipment).
The measuring voltages for the operating conditions are listed in table 1.
Performance test
Table 1
Measuring voltage UMDecoding
≤ 1 V Malfunction in electrode supply cable (short circuit or interruption)
1 V – 4 V Electrode exposed, fluid temperature ≥ 395 °C
4 V – 7 V Electrode submerged, HIGH level
≥ 9 V Malfunction in electrode (defective insulating seal, leaky stuffing box)
Danger
The screw-type connector of the NRS 2-4 c/d is live during operation.
This presents the danger of electric shock!
Cut off power supply before inserting or removing the 19" slide-in unit and before carrying
out any installation or maintenance work.

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Fault finding list for troubleshooting
Operational Malfunctions
Danger
The screw-type connector of the NRS 2-4 c/d is live during operation.
This presents the danger of electric shock!
Cut off power supply before inserting or removing the 19" slide-in unit and before carrying
out any installation or maintenance work.
If faults occur that are not listed above or cannot be corrected, please contact our service centre or
authorized agency in your country.
LED “Power” is not illuminated.
Fault: Power failure
Remedy: Measure voltage across A/C 28 and A/C 30, check voltage supply and electric connection
LED “Malfunction in level electrode” and LED “High level alarm” are illuminated.
Fault: The safety screw of the level electrode has not been removed
Remedy: Remove safety screw
Remedy: Level electrode (insulation, stuffing box) defective
Remedy: Measure measuring voltage across C 18 / A 18
Replace level electrode if measuring voltage ≥9 V
LED “Malfunction in connecting line” illuminated.
Fault: Electrode supply line defective (short circuited or interrupted)
Remedy: Check electrode supply line and wiring
High water level is exceeded but only the green LED “Power” is illuminated.
Remedy: Level electrode not submerged
Remedy: Measure measuring voltage across C 18 / A 18
If no voltage can be measured check and, if necessary, change installation of level electrode
Fault: Preamplifier in level electrode defective
Remedy: Replace preamplifier if the 12 V supply voltage for the electrode is present but no measuring
voltage can be measured across C 16 / A 18

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Note on the Declaration of Conformity / Declaration by the Manufacturer
Annex
For details on the conformity of our equipment according to the European Directives see our
Declaration of Conformity or our Declaration of Manufacturer.
The current Declaration of Conformity / Declaration of Manufacturer are available in the Internet
under www.gestra./de/documents or can be requested from us.

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For your notes

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810427-03/06-2016cm (808455-03) · GESTRA AG · Bremen · Printed in Germany
GESTRA AG
Münchener Straße 77
28215 Bremen
Germany
Telefon [phone]
Telefax [phone]
E-mail [email protected]
Web www.gestra.de
Agencies all over the world: www.gestra.de