Kobold NE-5048 User manual

Operating Instructions
for
Electrode Relays for
Conductive Limit Switches
Model: NE-5048
(without WHG-certification)

NE-5048
page 2 NE-5048 K02/0422
1. Contents
1.Contents ........................................................................................................ 2
2.Note .............................................................................................................. 3
3.Instrument Inspection .................................................................................... 3
4.Regulation Use ............................................................................................. 3
5.Operating Principle ........................................................................................ 4
6.Mechanical Connection ................................................................................. 5
7.Electrical Connection .................................................................................... 5
7.1.Electrode relay NE-5048 ...................................................................... 5
7.2.Process Applications NE-5048 ............................................................ 7
8.Locating and Remedying Faults .................................................................... 9
9.Maintenance ................................................................................................. 9
10.Technical Information .................................................................................. 10
11.Order Codes ............................................................................................... 10
12.Dimensions ................................................................................................. 11
13.EU Declaration of Conformance ................................................................. 12
Manufactured and sold by:
Kobold Messring GmbH
Nordring 22-24
D-65719 Hofheim
Tel.: [phone]
Fax: [phone]
E-Mail: [email protected]
Internet: www.kobold.com

NE-5048
NE-5048 K02/0422 page 3
2. Note
Please read these operating instructions before unpacking and putting the unit
into operation. Follow the instructions precisely as described herein.
The instruction manuals on our website www.kobold.com are always for currently
manufactured version of our products. Due to technical changes, the instruction
manuals available online may not always correspond to the product version you
have purchased. If you need an instruction manual that corresponds to the
purchased product version, you can request it from us free of charge by email
([email protected]) in PDF format, specifying the relevant invoice number and
serial number. If you wish, the operating instructions can also be sent to you by
post in paper form against an applicable postage fee.
The devices are only to be used, maintained and serviced by persons familiar
with these operating instructions and in accordance with local regulations
applying to Health & Safety and prevention of accidents.
When used in machines, the NE-unit should be used only when the machines
fulfil the EC-machine guidelines.
3. Instrument Inspection
The instruments are inspected before shipping and sent out in perfect condition.
Should damage to the instrument be visible, we recommend close inspection of
the delivery package. In cases of damage, please immediately inform the
forwarder as he is liable for any damage in transit.
Scope of delivery
 Conductive Electrode Relay model: NE-5048
4. Regulation Use
The Conductive Limit Switch has been designed for use in level monitoring
applications and for pump control for low to highly conductive liquids. The switch
has no moving parts—thus, it is particularly suited for monitoring critical media
with low solid contents, low density, or high viscosity.
It comprises conductive electrodes and an electrode relay.
The medium conductivity must be min. 10S/cm.

NE-5048
page 4 NE-5048 K02/0422
Electrode relay
The model NE-5048 electrode relay controls the conductive electrodes and
switches throughput, when the conductivity changes.
Type 5048: For one switching point with one electrode and one earth
electrode. The relay can be operated in interval mode with two electrodes and
one earth electrode.
Electrodes
Two types of conductive probes are available: solid rod or flexible pendant
electrodes; they are vertically mounted in the tank to be monitored. The
electrode length corresponds to the switching point.
5. Operating Principle
The KOBOLD electrode relays type NE-5048 are used in conjunction with the
conductive limit switches NES, NEH and LNK (option without electronic module)
for level monitoring and level control of conductive liquids with a conductivity of
more than 10 μS/cm.
Probes are immersed in the tank to detect the level. These probes (and the tank
wall, if conductive) serve as contacts of a circuit. The probes can be single-rod or
multi-rod probes (see also NES and NEH).
The NE-5048 relay provides a limit value signal for connecting one control and
one earth electrode.
It also includes a bistable interval relay with latching and is thus suitable for
interval switching - e.g. for pump control (min./max. control).

NE-5048
NE-5048 K02/0422 page 5
6. Mechanical Connection
The electrodes can be screwed into the tank cover via a pipe thread and sealed,
for example. The electrode length corresponds to the desired switching points,
and rod electrode lengths may be shortened. The electrode tip must be free of
insulating materials. The electrodes must be installed so that the electrode rods
or the pendant electrodes are not short-circuited with the side of the tank, or with
each other. Please ensure that the rods cannot buckle, or that the pendant
electrodes cannot become knotted.
The reference or earth electrode must be at least as long as the longest switching
electrode. If the side of the tank is adequately conductive and is not coated with
insulating material, it can be used as an earth electrode. The clearance between
the switching electrode and the side of the tank should be as small as possible,
so that the conductivity of the measuring distance does not fall below 10S/cm.
7. Electrical Connection
Attention! Make sure that the voltage values of your system
correspond with the voltage values of the measuring unit. Make sure
that the supply wires are de-energised.
Attention! The unit has a basic isolation between power terminals
A1, A2 and measurement terminals D, H, C, which is dimensioned
according to overvoltage category II. In this sense, the input
measuring circuit is electrically isolated from the power supply
terminals.
Maximum cable length: 300 m, minimum cross-section 0,5 mm². A
screened, low capacity cable is to be used at a cable length of
approx. 15 m and near EMC-critical installation environement. The
cable needs to be connected to an adequate shield ground.
7.1. Electrode relay NE-5048
The NE-5048 electrode relay is the standard relay for all conductive limit
electrodes. The relay is supplied in closed-circuit current version.
The function can be adapted to your application according to the following
explanations.
The red LED signal lamp lights up when the relay is energised.
The green LED lights up when the supply voltage is applied.

NE-5048
page 6 NE-5048 K02/0422
The relay is intended for monitoring the level in conductive liquids, with the
following functions to choose from: pump up or pump down (PUMP UP or PUMP
DOWN).
To prevent polarisation or undesirable oxidation of the sensors, the measuring
circuit is supplied with alternating current.
There are 3 probes for the measurement: H - upper probe, D - lower probe and C
- common probe.
If a container made of conductive material is used for the measurement, the
container wall can also be used as sensor C. If you want to monitor only 1 level,
the inputs dog D must be connected and connected to 1 sensor. In this case the
input resistance is reduced by half (2.5...50 KΩ instead of 5-100 KΩ). Sensor C
can also be connected to a protective earth conductor of the supply system (PE).
To avoid unwanted switching (due to sensor contamination caused by sediments,
humidity...), the sensitivity of the device can be set in the range of 5 to 100 KΩ
depending on the conductivity of the monitored liquid (resistance of the liquid).
To avoid unwanted switching of the output contacts due to an unstable surface of
the liquid or wave movements in the tank,
you can set a delay in the output of 0.5-10 s.
Power supply connection
The mains voltage is connected to terminals A1 and A2

NE-5048
NE-5048 K02/0422 page 7
7.2. Process Applications NE-5048
1 Level Monitoring
2 Level Monitoring
NE Switch
A1, A2: Power supply
C: Reference electrode
H: MAX maximal level electrode
D: MIN minimal level electrode

NE-5048
page 8 NE-5048 K02/0422
Filling function
Emptying function

NE-5048
NE-5048 K02/0422 page 9
8. Locating and Remedying Faults
The relay does not operate:
 Check whether the mains voltage is applied to terminals A1 and A2 (green
LED lights up).
 If the LED lights up
Disconnect electrodes from terminals C, H, D and short-circuit terminals C and
H, D with a wire jumper. The relay must now react according to the function of
the presetting. If there is no reaction, there is a fault in the relay.
 If the relay switches, remove the short-circuiting link and connect the
electrodes according to the connecting instructions. Short-circuit the electrodes
at the tips with a wire jumper. If the relay does not change over now, there is a
cable interruption, or the electrode tips are insulated by deposits.
 If the relay with the wire jumper at the electrode tips changes over, remove the
wire jumper, adjust the maximum sensitivity on the relay, and immerse the
electrodes in the medium. If the relay still does not switch, the conductivity of
the medium may be too low.
9. Maintenance
The conductive limit switch requires absolutely no maintenance. The electrode
tips should be occasionally inspected for deposits or corrosion, and should be
cleaned. Insulating deposits can cause a malfunction.

NE-5048
page 10 NE-5048 K02/0422
10. Technical Information
NE-104, NE-304
Power supply: 24-240 VAC/DC
(AC 50 – 60 Hz) - 15%, +10%;
Power input: max. 2 VA/1.5W
Floating voltage: max. 3.5 VAC 10 Hz
Short-circuit-current: <0.1 mA AC
Sensitivity: adjustable 5 – 100 kΩ
Response time: 400 ms
Switch-on delay: 1.5 s
Switch-off delay: adjustable 0.5-10 s
Output: 1 potential-free change-over contact
Switching capacity: max. 250 VAC, 8 A, 2000 VA (AC)
240 W (DC)
Housing: Macrolon®
Protection class housing: IP 40
Protection class terminals: IP 10
Ambient temperature: -20 °C...+55 °C
Dimensions: 90 x 17.6 x 64 mm
Weight: 73 g
Mounting: Quick mounting for standard rail DIN 60715
Visual indication of
operating status: LED red Monitoring state
LED green Operating voltage
11. Order Codes
Example: NE-504 8
Model Description Number of outputs Power supply
NE- Elektrode relay 504 = 1 limit signal or
1 Min./Max. controller 8 = 24 - 240 VAC/DC