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Issue Date: 12/02 GESTRA ® Industrial Electronics · Product Range Group B1 NRS 2-3 Level Switch Type NRS 2-3 Level switch NRS 2-3 NRS 2-3 MAX MIN OFF ON Purpose and Application The level switch type NRS 2-3 is an analogue electronic control instrument for the capacitance level electrode NRGT 26-1. In combination with this compact electrode the switch can signal the following levels High level, low level, level control unit ON/OFF and can be used as level controller for steam boilers and pressurized hot-water plants. Examples of installation Use level switch NRS 2-3 only in combination with GESTRA compact electrode type NRGT 26-1. Design Design “b” 19" slide-in unit to DIN 41494 part 5, installed on a mounting panel for installation in control cabinets with screw-type terminals at the top and bottom. Design “c” 19" slide-in unit with guide rails and 32 pole screw-type connector for the installation in 19" mounting panels acc. to DIN 41494 part 5. Design “d” 19" spare slide-in unit Function The level transmitter NRGT 26-1 provides a current signal in proportion with the measured liquid level. This signal is converted into a voltage, which is then fed to three voltage comparators, V1, V2 and V3. The reference voltages of these comparators may be indi- vidually set by the adjustors of the face plate of the NRS 2-3. Depending on the relationship of the signal voltage to the adjusted reference voltage, the related relays behave as follows: The level signal voltage across V1 is higher than the reference voltage: Relay 1 is de- energised, and the red LED is illuminated. The level signal voltage across V1 is lower than the reference voltage: Relay 1 is ener- gised, and the red LED is extinguished. The level signal voltage across V3 is lower than the reference voltage: Relay 3 is de- energised, and the red LED is illuminated. The level signal voltage across V3 is higher than the reference voltage: Relay 3 is ener- gised, and the red LED is extinguished. V2 is used to operate, for example, boiler feed pump ON/OFF control, and this is established by adjustment of the reference voltage of V2, and separate adjustment of hysteresis in the 1 % to 50 % of measuring range. The level signal voltage across V2 is lower than the reference voltage: Relay 2 switches on the pump and the yellow LED is illu- minated. The level signal voltage across V2 is higher than the reference voltage plus hysteresis: relay 2 switches off the pump and the green LED is illuminated. D D A A B C Technical Data Type approval no. GL 99249-96HH Mains voltage 230 V ± 10%, 50/60 Hz 115 V ± 10%, 50/60 Hz (option) 24 V ± 10%, 50/60 Hz (option) Power consumption 5 VA Input 4 – 20 mA (coming from level transmitter) Output 3 volt-free relay contacts Max. contact rating with switching voltages of 24 V, 115 V and 230 V AC: 4 A resistive, 0.75 A inductive at cos ϕ = 0.5. Max. contact rating with a switching voltage of 24 V DC: 4 A Service life of relay: 30 x10 6 switching cycles. Limit value HIGH LEVEL / LOW LEVEL Continuously adjustable within measuring range of level transmitter Switchpoints Pump ON / OFF Continuously adjustable within 1 – 50 % of the measuring range of level transmitter Indicators and adjustors 1 red LED “HIGH LEVEL”, 1 red LED “LOW LEVEL”, 1 yellow LED “PUMP ON”, 1 green LED “PUMP OFF”. 4 adjustors for HIGH LEVEL / LOW LEVEL and PUMP ON / OFF. Protection IP 10 to DIN 40050 Max. admissible ambient temperature 0 °C to +70 °C Case 19" slide-in unit with front panel to DIN 41494 part 5 and rear 32 way Euro card connector to DIN 41612 installed in a mounting panel or for installation in 19" mounting panel. Front panel, mounting panel: aluminium Wiring Design “b”: screw-type terminal strips at the back of the mounting panel, max. conductor size 1.5 mm² Design “c”: 32 pole screw-type connector at the back of the 19" mounting panel, max. conductor size 1.5 mm² Supply line to compact electrode: screened two- core cable, conductor size 0.5 mm², max. cable length 150 m Internal fuse Glass cartridge fine-wire fuse M 0.05 M, 5 x 20, replaceable Weight approx. 0.8 kg

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Page 1: GESTRA Industrial Electronics · Product Range …® Industrial Electronics · Product Range Group B1 NRS 2-3 Level Switch Type NRS 2-3 Level switch NRS 2-3 NRS 2-3 MAX …

Issue Date: 12/02

GESTRA® Industrial Electronics · Product Range Group B1

NRS 2-3Level SwitchType NRS 2-3

Level switch NRS 2-3

NRS 2-3

MAX

MIN

OFF

ON

Purpose and ApplicationThe level switch type NRS 2-3 is an analogueelectronic control instrument for the capacitancelevel electrode NRGT 26-1.

In combination with this compact electrode theswitch can signal the following levels

■ High level, low level, level control unit ON/OFF

and can be used as level controller for steamboilers and pressurized hot-water plants.

Examples of installationUse level switch NRS 2-3 only in combinationwith GESTRA compact electrode type NRGT26-1.

DesignDesign “b”19" slide-in unit to DIN 41494 part 5, installed ona mounting panel for installation in controlcabinets with screw-type terminals at the top andbottom.

Design “c”19" slide-in unit with guide rails and 32 polescrew-type connector for the installation in 19"mounting panels acc. to DIN 41494 part 5.

Design “d”19" spare slide-in unit

FunctionThe level transmitter NRGT 26-1 provides acurrent signal in proportion with the measuredliquid level. This signal is converted into avoltage, which is then fed to three voltagecomparators, V1, V2 and V3. The referencevoltages of these comparators may be indi-vidually set by the adjustors of the face plate ofthe NRS 2-3. Depending on the relationship ofthe signal voltage to the adjusted referencevoltage, the related relays behave as follows:

■ The level signal voltage across V1 is higherthan the reference voltage: Relay 1 is de-energised, and the red LED is illuminated.

■ The level signal voltage across V1 is lowerthan the reference voltage: Relay 1 is ener-gised, and the red LED is extinguished.

■ The level signal voltage across V3 is lowerthan the reference voltage: Relay 3 is de-energised, and the red LED is illuminated.

■ The level signal voltage across V3 is higherthan the reference voltage: Relay 3 is ener-gised, and the red LED is extinguished.

V2 is used to operate, for example, boiler feedpump ON/OFF control, and this is established byadjustment of the reference voltage of V2, andseparate adjustment of hysteresis in the 1 % to50 % of measuring range.

■ The level signal voltage across V2 is lowerthan the reference voltage: Relay 2 switcheson the pump and the yellow LED is illu-minated.

The level signal voltage across V2 is higher thanthe reference voltage plus hysteresis: relay2 switches off the pump and the green LED is illuminated.

D

D

A

A

B

C

Technical DataType approval no.GL 99249-96HH

Mains voltage230 V ± 10 %, 50/60 Hz115 V ± 10 %, 50/60 Hz (option) 24 V ± 10 %, 50/60 Hz (option)

Power consumption5 VA

Input4 – 20 mA (coming from level transmitter)

Output3 volt-free relay contactsMax. contact rating with switching voltages of24 V, 115 V and 230 V AC: 4 A resistive, 0.75 Ainductive at cos ϕ = 0.5.Max. contact rating with a switching voltage of24 V DC: 4 AService life of relay: 30 x 106 switching cycles.

Limit value HIGH LEVEL / LOW LEVEL

Continuously adjustable within measuringrange of level transmitter

Switchpoints Pump ON / OFF

Continuously adjustable within 1 – 50 % of themeasuring range of level transmitter

Indicators and adjustors1 red LED “HIGH LEVEL”, 1 red LED “LOW LEVEL”,1 yellow LED “PUMP ON”, 1 green LED “PUMP OFF”.4 adjustors for HIGH LEVEL / LOW LEVEL and PUMP ON /OFF.

ProtectionIP 10 to DIN 40050

Max. admissible ambient temperature0 °C to +70 °C

Case19" slide-in unit with front panel to DIN 41494part 5 and rear 32 way Euro card connector toDIN 41612 installed in a mounting panel or forinstallation in 19" mounting panel.Front panel, mounting panel: aluminium

WiringDesign “b”: screw-type terminal strips at theback of the mounting panel, max. conductor size1.5 mm²Design “c”: 32 pole screw-type connector atthe back of the 19" mounting panel, max.conductor size 1.5 mm²Supply line to compact electrode: screened two-core cable, conductor size 0.5 mm², max. cablelength 150 m

Internal fuseGlass cartridge fine-wire fuse M 0.05 M, 5 x20,replaceable

Weightapprox. 0.8 kg

Page 2: GESTRA Industrial Electronics · Product Range …® Industrial Electronics · Product Range Group B1 NRS 2-3 Level Switch Type NRS 2-3 Level switch NRS 2-3 NRS 2-3 MAX …

GESTRA GmbHP. O. Box 10 54 60, D-28054 BremenMünchener Str. 77, D-28215 Bremen

Tel. +49 (0) 421 35 03 - 0, Fax +49 (0) 421 35 03 - 393E-Mail [email protected], Internet www.gestra.de

810435-01/1202c · © 1998 GESTRA GmbH · BREMEN · Printed in Germany

®

Technical Data – continued –

Scope of supplyNRS 2-3, design “b”1 Level switch NRS 2-31 Mounting panel for installation in control

cabinets1 Installation instructions

NRS 2-3, design “c”1 Level switch NRS 2-32 Guide rails1 32 pole screw-type connector1 Installation instructions

NRS 2-3, design “d”1 Level switch NRS 2-31 Installation instructions

Supply in accordance with our general terms ofbusiness.

Level SwitchType NRS 2-3

16945.3

(9 TE)

128.

5

207

180

88

∅6

8067.7

Wiring diagrams

Desing “b”

Dimensions

Compact electrode

High level

Water level controller (fill control)

Low level, 2nd water level indicator: LED red/green

Connection for another device, e. g. NRR 2-3

1

2

3

4

5

2

3

4

1

5

Design “c” / “d”

1

5

2

3

4

Important NoteNote that screened four-core cable is requiredfor wiring, e.g. I-Y(St)Y 2 x 2 x 0.8 or LIYCY4 x 0.5 2. Max. cable length 100 m.

To protect the switching contacts fuse circuit with2.5 A (slow-blow) or according to TRD regulations(1.0 A for 72 h operation).

Order & Enquiry SpecificationGESTRA Level switch NRS 2-3

Design .......................

Mains voltage .............V

Associated Equipment■ Conductivity electrode NRGT 26-1S for level

monitoring.