Kobold NBK-19 User manual
Operating Instruction
for
Bypass-
Level Indicator
Cable version
Model: NBK-19
NBK-19
Seite 2 NBK-19 K03/0322
1. Contents
1.Contents ........................................................................................................ 2
2.Note .............................................................................................................. 3
3.Instrument Inspection .................................................................................... 3
4.Regulation Use ............................................................................................. 4
5.Operating Principle ........................................................................................ 4
6.Mechanical connection .................................................................................. 5
7.Electrical connection ..................................................................................... 6
7.1Limit contact (optional) ......................................................................... 6
7.2Measurement transducer Reed contact chain (option ..W..) ............... 6
7.3Measurement transducer: Reed chain with 2-wire transmitter (option
..M..)..................................................................................................... 7
7.4Measurement transducer: Magnetostrictive sensor with 4-wire
transmitter (option ..T..) ........................................................................ 8
8.Operation ...................................................................................................... 9
8.1Operation of the level indicator ............................................................ 9
8.2Operation of the electrical limit contact ................................................ 9
9.Fault diagnosis and dealing with malfunctions ............................................ 10
10.Technical information .................................................................................. 11
11.Order information ........................................................................................ 13
12.Dimensions ................................................................................................. 14
13.EU Declaration of Conformance ................................................................. 16
14.UK Declaration of Conformity ...................................................................... 18
Manufactured and sold by:
Kobold Messring GmbH
Nordring 22-24
D-65719 Hofheim
Tel.: +49(0)6192-2990
Fax: +49(0)6192-23398
E-Mail: [email protected]
Internet: www.kobold.com
NBK-19
NBK-19 K03/0322 Seite 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 measuring unit should be used only when the
machines fulfil the EC-machine guidelines.
3. Instrument Inspection
Instruments are inspected before shipping and sent out in perfect condition.
Should damage to a device be visible, we recommend a thorough inspection of
the delivery packaging. In case of damage, please inform your parcel service /
forwarding agent immediately, since they are responsible for damages during
transit.
Scope of delivery:
The standard delivery includes:
Measuring tube
Float
Magnet system
2 x deflection pulleys
2 or 3 fastening clamps
cable with 2 simplex-clamps
NBK-19
Seite 4 NBK-19 K03/0322
4. Regulation Use
Any use of the Bypass-Level Indicator, model: NBK-19, which exceeds the
manufacturer’s specifications, may invalidate its warranty. Therefore, any
resulting damage is not the responsibility of the manufacturer. The user assumes
all risk for such usage.
5. Operating Principle
The Kobold bypass level indicator type NBK-19 is based on the simple principle
of cable and deflection pulley. The tank float, made of PPH or stainless steel, is
moved upwards and downwards by the medium according to the liquid level in
the tank. The tank float has a counter float (counterweight) which moves in a
transparent PVC tube depending on the liquid level. The two floats are connected
to each other through a cable and 2 deflection pulleys. The magnetic counter float
has a ring marker for reading of the scale on the bypass PVC tube.
The following options are available:
Magnet roller indicator
When the counter float travels past the red/white rollers, they rotate through
180°. The rollers change from white to red when the liquid level rises and from
red to white when the level falls. The liquid level is continuously indicated as a
red column, even in the event of a power outage.
Measurement transducer:
For remote transmission of the liquid level, a measurement transducer with
reed chain or a magnetostrictive sensor can be mounted on the outside of the
bypass tube. Using a built in transducer, a continuous standard signal of 4 to
20 mA is transmitted. This standard signal can be displayed using an
analogue or digital indicator device.
Universal indicator device:
An ADI series universal indicator device can be connected to indicate and
evaluate the standard signal (4 to 20 mA) produced by the measurement
transducer. For reasons of stability, this device is not mounted on the bypass
tube, but is supplied with wall mountings.
Limit contacts:
One or more reed contacts can be attached to the bypass tube to monitor the
limit values or to control the liquid level.
NBK-19
NBK-19 K03/0322 Seite 5
Maximum values Standard
contact
Switching capacity: 60 W/VA
Switching current: 1 A
Switching voltage: 230 VAC/DC
Warning! Always observe the allowable power/current carrying
capacity and maximum voltage for the limit contacts.
6. Mechanical connection
Affix the pipe clamps supplied at the relevant vertical height (for sizes, see
section 12 Dimensions) to the tank or in an appropriate manner.
Remove the packaging from the bypass float, pull the float a little upwards in
the tube and fix in place.
Snap the bypass tube into the pipe clamps, adjust and place the lower end of
the tube onto a support (floor).
Bolt the bypass tube to the pipe clamps.
Affix the loose roller bearings supplied onto the tank, such that a cable can be
introduced into the tank without being impeded.
Run the cable over the pulley into the tank and affix the tank float using the
simplex clamps, such that the level in the tank corresponds to the scale on the
bypass tube.
NBK-19
Seite 6 NBK-19 K03/0322
With cable
connection
blue
brown
black
7. Electrical connection
7.1 Limit contact (optional)
Connect the limit contact, where used, as shown in
the wiring diagram and connect to the electrical
control system.
When connecting inductive loads such as
contactors, relays, etc, it must be ensured that the
electrical limit values are not exceeded, even for
short periods such as with voltage spikes.
To prevent overloading of the reed contact, it is
recommended that a contact protection relay is
used.
7.2 Measurement transducer
Reed contact chain (option ..W..)
Ensure that the electrical power supply is deenergised.
To avoid disturbances from electric fields of other electrical circuits, the cable
should not be laid together with other high voltage cables.
Remove the cover and run the power supply cable through the cable gland.
Connect the measurement transducer to the electronic system in accordance
with the following table.
Measurement
transducer
”upper” 1
Measurement
transducer
”lower” 2
Tap
3
Connector
housing
Clamp 1 Clamp 2 Clamp 3
Internal* yellow red black
upper
lower
tap
Please note: The colours of the internal cables are for internal
connections only, and are therefore only visible for measurement
transducers which have a connector housing.
If connecting the measurement transducer to a Kobold transmitter, such as type
ADI, please read the relevant operating instructions.
NBK-19
NBK-19 K03/0322 Seite 7
7.3 Measurement transducer: Reed chain with 2-wire transmitter
(option ..M..)
Ensure that the electrical power supply is deenergised.
To avoid disturbances from electric fields of other electrical circuits, the cable
should not be laid together with other high voltage cables.
Remove the cover and run the power supply cable through the cable gland.
Connect the transmitter as shown in the following wiring diagram.
+
-
+
-
16-32 V DC
+
-
NBK-19
Seite 8 NBK-19 K03/0322
7.4 Measurement transducer: Magnetostrictive sensor with
4-wire transmitter (option ..T..)
Ensure that the electrical power supply is deenergised.
To avoid disturbances from electric fields of other electrical circuits, the cable
should not be laid together with other high voltage cables.
Remove the cover and run the power supply cable through the cable gland.
Connect the transmitter as shown in the following wiring diagram.
4-20 mA 24 VDC
± 20%
A
out AGND + US GND
GND
+Us
AGND
AOUT
+
-
4-20 mA
24 V DC
+
-
NBK-19
NBK-19 K03/0322 Seite 9
8. Operation
8.1 Operation of the level indicator
The screw connections should be checked and tightened where necessary.
Fill the container and switch on the electrical control system, where used.
The liquid, which now enters the tank, raises the tank float and lowers the bypass float,
which then shows the level of liquid in the tank in the bypass tube and on the scale or
the roller indicator where present.
8.2 Operation of the electrical limit contact
Function of the limit contacts
All contacts have three terminals (black, blue and brown). The black wire represents
the common terminal for both switches (N/C and N/O).
So that the switch function corresponds to the wiring diagram / the table below, the
float must pass the contact once in both directions.
This point is frequently neglected where an alarm light is connected directly, and it is
assumed that the contact is defective.
The contact is ready for operation once the contact has been passed and does not
require any maintenance.
Black / blue Black / brown
Float above open electricall
y
conductin
g
Float below electricall
y
conductin
g
open
Hysteresis
The difference between the points at which the contact switches
on and off is known as the hysteresis. Factory tuning of the float
magnet contact strength gives a hysteresis of about 15 mm of
vertical travel of the float.
NBK-19
Seite 10 NBK-19 K03/0322
9. Fault diagnosis and dealing with malfunctions
Fault / malfunction Possible cause
The cable is loose when the tank is full The bypass float is resting on the base of
the tube. The cable is too lon
g
.
The bypass float knocks against the head
of the tube.
The tank float is partly or completely out of
the medium in the tank. The cable is too
short.
The tank and bypass floats no longer
move. The cable is caught.
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