Kobold SCH User manual
Operating Instructions
for
Pressure Switch
Model: SCH
SCH
page 2 SCH K03/0320
1. Contents
1.Contents ........................................................................................................ 2
2.Note .............................................................................................................. 3
3.Instrument Inspection .................................................................................... 3
4.Regulation Use ............................................................................................. 3
4.1Installation and Commissioning ........................................................... 4
4.2Safety Instructions ............................................................................... 4
5.Mechanical Connection ................................................................................. 5
6.Electrical Connection .................................................................................... 6
7.Setting the Switching Pressure ..................................................................... 7
7.1Setting the Switching Pressure with Plug Connection ......................... 7
7.2Setting the Switching Point .................................................................. 7
7.3Setting Switching Difference (only model V) ........................................ 8
8.Special Functions .......................................................................................... 9
8.1Maximum- and Minimum Pressure Limiter (-205 and -206) ................. 9
8.2Two Stage Pressure Switches (- 307 and - 217) ................................. 9
8.3Switching Interval and Schematic Wiring Diagrams ........................... 11
8.4Gold Plated Contacts (-213) .............................................................. 13
8.5SCH-EX- (EEx-d-Version) .................................................................. 13
9.Technical Information .................................................................................. 14
9.1Technical Information SCH-Ex units .................................................. 14
10.Order Codes ............................................................................................... 14
11.EU Declaration of Conformance ................................................................. 15
12.Examination Certificate ............................................................................... 16
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
SCH
SCH K03/0320 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 devices are only to be used, maintained and serviced by persons familiar
with these operating instructions and in accordance with local regulations apply-
ing 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.
as per PED 2014/68/EU
In acc. with Article 4 Paragraph (3), "Sound Engineering Practice", of the PED
2014/68/EU no CE mark.
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:
Pressure Switch model: SCH
Operating Instructions
4. Regulation Use
Any use of the “SCH”, which exceeds the manufacturers specification may invali-
date its warranty. Therefore, any resulting damage is not the responsibility of the
manufacturer. The user assumes all risk for such usage.
Pressure Switches are used for controlling and monitoring pressure in vessels of
all kinds, e.g. for boilers, compressed air reservoirs, hydraulic and pneumatic
plant, refrigeration engineering, water supply systems etc. Suitable types are
available for overpressure, differential pressure and vacuum.
SCH
page 4 SCH K03/0320
4.1 Installation and Commissioning
Pressure switches must be installed only by personnel trained in this
application area (electric/hydraulic/mechanical) in accordance with the
installation instructions and local legal requirements.
The devices must be installed (mechanical, pressure-side connection) only
on electro-chemically matched materials, otherwise there is risk of damage
to base metals through contact corrosion which can result in loss of
stability and leakage.
Caution when touching device – risk of burns. Device can reach a medium
temperature of up to 70 °C. Risk of freezing when working with media up
to -20 °C.
Do not open wiring-box or plug and do not remove terminal screws before
the device is de-energized.
Ex versions are limited to an operating range of -20 … +60 °C.
4.2 Safety Instructions
The device must only be used within the electric, hydraulic and thermal
limits specified in the data sheet.
Inductive loads can cause contact burns or fuse the contacts. Preventative
measures must be implemented by the customer, e.g., through use of
suitable RC elements.
When using the version with ZF 1979 (oil and grease-free), take care to
avoid recontamination of surfaces that are in contact with media, right
through from opening the packaging to completed installation. Generally,
no liability will be assumed for oil and grease-free version.
High quality stainless-steel sensor parts in contact with media enable the
devices to be used with a variety of media. However, a chemical
resistance test MUST be carried out before selection.
Use with acids and other aggressive media, such as hydrofluoric acid,
copper chloride, aqua regia or hydrogen peroxide, is not permitted.
Use in systems with unstable gases and liquids such as hydrogen cyanide,
dissolved acetylene or NOx is not permitted.
Devices must be protected from solar radiation and rain.
Pressure switches are precision devices which are calibrated in the
factory. For this reason, never open the device and do not change the
adjustment of the varnished calibration screws.
Prevent excessive vibrations from reaching the pressure switch, e.g., with
mechanical isolation or other vibration damping measures.
Heavily contaminated media can clog the sensor and cause errors and/or
malfunction. If the equipment is to be used for this purpose, suitable
chemical seals must be connected.
Pressure switches and chemical seals form a functional unit and must not
be disconnected from each other in the field.
Before disassembly (removing the pressure switch from the system), the
device must be disconnected from the power supply and the system must
be emptied. Observe the Accident Prevention Regulations.
Never use the pressure switches as a climbing aid.
KOBOLD Messring GmbH accepts no liability for non-compliance.
SCH
SCH K03/0320 page 5
5. Mechanical Connection
Installation
Install directly on the pipeline (pressure gauge connection G 1/2) or with 2 screws
(4 mm) surface mounting. Tighten only on the hexagonal of the pressure
connection, never use the housing or plug for fixing.
Connection
The differential Pressure Switches SCH- DDCM have 2x G 1/4 internal thread
connections. Connect the high and the low pressure according to the marks.
(+) = high pressure
(-) = low pressure
When connecting attention should be paid to the marks.
External thread G 1/2
(Pressure gauge
connection)
When using flat seals,
turn insert the centring
screw.
Internal thread G 1/4
(Remove the centering peg )
In gas application internal
thread only up to 4 bar
permissible. Use flat gasket ring
for higher pressure.
SCH
page 6 SCH K03/0320
6. Electrical Connection
Ensure that the power is disconnected during connection of the cable.
Wiring is on the angled plug.
The cable outlet can be in any of 4 positions, which are at 90° in relation to
each other.
Remove screw
Insert the screw driver in the slot and press downwards.
On devices with terminal connection housing the terminal board is available
after removing the terminal box lid.
Attention! The Pressure Switches are precision instruments, set and
adjusted at the factory. Do not open the device or re-set the
varnished adjustment screw. This would alter the switching points
and resetting would be necessary.
With rising pressure:
3-1 opens, 3-2 closes
With falling pressure:
3-2 opens, 3-1 closes
SCH
SCH K03/0320 page 7
7. Setting the Switching Pressure
7.1 Setting the Switching Pressure
with Plug Connection
The switching pressure is set using the
setting spindle. Before setting loosen the
locking screw located above the scale by
approx. 2 turns and tighten it again after
setting. The scale value corresponds to the
upper switching point (for rising pressure).
The lower switching point (for falling
pressure) is lower by the value of switching
difference. The scale serves only as an
estimated value scale, a pressure gauge is
required for accurate settings.
On the pressure switch housing, the setting
screw is accessible after removing the cover.
Attention: Switch off voltage !
Switching pressure
turn to the right: lowers switch point
turn to the left: raises switch point
7.2 Setting the Switching Point
The switching point can be set within the range given in the datasheet by using a
screwdriver on the setting spindle. Additionally you should remove the terminal
board casing (with 4 hexagon screw M 4). The affixing screw on the front end
(above the scale) has to be removed and should be reattached after setting the
switching point.
Turning the setting spindle clockwise gives a lower switching point, turning
anticlockwise gives a higher switching point.
The scale should be used as a guide, for more exact settings you should use a
manometer.
SCH
page 8 SCH K03/0320
Serial Numbers
All switch units and their respective terminal board casings are marked with a
serial number. When installing you should ensure that the terminal board casings
do not get mixed up.
Note: When installing the Ex switch units and setting them up for
operation you should comply with the recognised rules and
guidelines for installations in Ex-areas.
7.3 Setting Switching Difference (only model V)
One spindle each is available for setting the switching pressure and the switching
difference. Both spindles are arranged concentrically. The outer spindle, with
larger diameter, adjusts the lower switching point; the switching difference, and
thus the upper switching point, is changed with the small central screw located
internally.
The action direction is indicated by the arrow direction.
Setting sequence
Adjust the lower switching point (with decreasing pressure), with outer spindle,
according to scale or pressure gauge.
Adjust the switching difference (with increasing pressure), with small, internal
central screw, results in setting the upper switching point.
When the switching difference is changed, the lower switch-off point remains
unchanged, the upper switching point is shifted by the switching difference.
xd= switching difference
(hysteresis)
SP= switching point
RSP= switch back point
SCH
SCH K03/0320 page 9
8. Special Functions
8.1 Maximum- and Minimum Pressure Limiter (-205 and -206)
Instead of a microswitch with automatic reset, a "bistable" microswitch is installed
in the limiters. When the pressure reaches the value set on the scale, the
microswitch switches over and remains in the position.
Unlocking
The catch can be released by pressing in the unlocking
button (marked on the scale side of the switching device by
a red dot.) The limiter can not be unlocked until the
pressure has decreased by a certain amount or, in the case
of interlocking at the lower switching point, is increased
again. Depending on the version, the interlock can be
effective for a rising value (max. limiter ...-205) or for a
falling value (min. limiter ...206).
8.2 Two Stage Pressure Switches (- 307 and - 217)
A switch-unit, with two microswitches both with single-poled changeover, forms
part of the basic equipment for each two-stage Pressure Switch.
The first switch I monitors lower pressure
The second switch II monitors higher pressure.
It should be noted that the switching differentials of the individual
microswitches cannot be exactly identical because of their component
tolerances.
The switching interval of both microswitches is the interval (in bar or mbar)
between the switching points of both microswitches.
Applies for all variations:
Changes to the setting spindle, to the setting of switching pressure, do not lead to
changes in the switching intervals as the switching points are adjusted corre-
spondingly. The switching differential of the individual microswitches corresponds
to the switching differences listed under basic equipment.
Minimum pressure limiter Maximum pressure limite
r
SCH
page 10 SCH K03/0320
The switching differential cannot be set for individual microswitches in two-
stage Pressure Switches.
Two stage Pressure Switch - 307
The switching interval between both switches is
set according to the customer’s requirements.
With increasing pressure first microswitch I
(terminal connection 1-3) and then
microswitch II (terminal connection 4-6) is
activated.
Two stage Pressure Switch - 217
as in -209 however the switching interval can be set within given limits.
Setting wheel I CW-reduce switching point at
microswitch I
Setting wheel II CCW-raise switching point at
microswitch II
Setting wheels I and II have an internal stop to ensure that the microswitches
cannot be adjusted past their effective range.
Attention: Note the sticker besides the plug connection of Pressure
Switch.
This manual suits for next models
17
Table of contents
Other Kobold Switch manuals
Kobold
Kobold NE-104 User manual
Kobold
Kobold TWR-1 Series User manual
Kobold
Kobold RFS User manual
Kobold
Kobold PSD User manual
Kobold
Kobold NSED User manual
Kobold
Kobold TWR User manual
Kobold
Kobold BVO Series User manual
Kobold
Kobold PSC series User manual
Kobold
Kobold NBK-RV200NO User manual
Kobold
Kobold PPS User manual
Kobold
Kobold NSP User manual
Kobold
Kobold LNK-K User manual
Kobold
Kobold SCH-27 User manual
Kobold
Kobold PDD Series User manual
Kobold
Kobold NEK Series User manual
Kobold
Kobold NSM User manual
Kobold
Kobold NBK-RA User manual
Kobold
Kobold NBA-2 User manual
Kobold
Kobold NV Series User manual
Kobold
Kobold NSED User manual
