FISCHER DS34 User manual

Operation manual
DS34
Differential pressure switch
09005751 • BA_EN_DS34 • Rev. ST4-E • 08/22 *09005751*

| Masthead FISCHER Mess- und Regeltechnik GmbH
2/16 BA_EN_DS34
Masthead
Manufacturer: FISCHER Mess- und Regeltechnik GmbH
Bielefelderstr. 37a
D-32107 Bad Salzuflen
Telephone: [phone]
Telefax: [phone]
eMail: [email protected]
web: www.fischermesstechnik.de
Technical editorial team: Documentation representative: T. Malischewski
Technical editor: R. Kleemann
All rights, also those to the translation, reserved. No part of this document may
be reproduced or processed, duplicated or distributed using electronic systems
or any other form (print, photocopy, microfilm or another process) without the
written consent of the company FISCHER Mess- und Regeltechnik GmbH, Bad
Salzuflen.
Reproduction for internal use is expressly allowed.
Brand names and procedures are used for information purposes only and do
not take the respective patent situation into account. Great care was taken
when compiling the texts and illustrations; Nevertheless, errors cannot be ruled
out. The company FISCHER Mess- und Regeltechnik GmbH will not accept any
legal responsibility or liability for this.
Subject to technical amendments.
© FISCHER Mess- und Regeltechnik 2015
Version history
Rev. ST4-A 12/15 Version 1 (first edition)
Rev. ST4-B 08/20 Version 2 (corrections)
Rev. ST4-C 07/21 Version 3 (Technical data connection cable)
Rev. ST4-D 03/22 Version 4 (UKCA conformity)
Rev. ST4-E 08/22 Version 5 (micro switch (Z) added)

FISCHER Mess- und Regeltechnik GmbH Table of contents
BA_EN_DS34 3/16
Table of contents
1 Product and functional description............................................................................... 4
1.1 Delivery scope........................................................................................................................ 4
1.2 Product summary ................................................................................................................... 4
1.3 Intended use........................................................................................................................... 5
1.4 Function diagram.................................................................................................................... 5
1.5 Design and mode of operation ............................................................................................... 5
2 Assembly and Starting Operation ................................................................................. 6
2.1 General................................................................................................................................... 6
2.2 Process connection ................................................................................................................ 6
2.3 Electrical connections............................................................................................................. 6
2.4 Start-up................................................................................................................................... 7
3 Servicing .......................................................................................................................... 8
3.1 Maintenance........................................................................................................................... 8
3.2 Transport ................................................................................................................................ 8
3.3 Service ................................................................................................................................... 8
3.4 Disposal.................................................................................................................................. 8
4 Technical data ................................................................................................................. 9
4.1 General................................................................................................................................... 9
4.2 Input variables ........................................................................................................................ 9
4.3 Output parameters ................................................................................................................. 9
4.4 Measuring accuracy ............................................................................................................... 9
4.5 Electrical connection .............................................................................................................. 9
4.6 Operating conditions .............................................................................................................. 10
4.7 Construction design................................................................................................................ 10
5 Order codes ..................................................................................................................... 12
5.1 Accessories ............................................................................................................................ 12
6 Attachment ...................................................................................................................... 13

1 | Product and functional description FISCHER Mess- und Regeltechnik GmbH
4/16 BA_EN_DS34
1 Product and functional description
1.1 Delivery scope
• DS34 Differential pressure switch
• Operating Manual
1.2 Product summary
12
3
4
5
6
7
8
9
Fig.1: Product summary
1 Connection cable 2 Housing
3 Mounting foot 4 Setting mark
5 Adjustment spindle 6 Scale plate
7 Pneumatic plug-in connection 8 Type plate
9 Cable screw connection
1.2.1 Process connection
The device has a process connection G⅛ inch internal thread as standard. The
device can also be supplied with pneumatic plug connections for 6 or 8 mm
hose.
CAUTION
Maximum tightening torque
The maximum tightening torque for the G⅛ inch internal thread is 5 Nm.

FISCHER Mess- und Regeltechnik GmbH Product and functional description | 1
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1.2.2 Type plate
Marking
Process connection
Order code
Serial number
Labelling
Article no.
Switching range
Breaking capacity
Pmax
Prod.-no.
DS34ABF043A1
0,1 ... 1 bar
3A/250V~
16 bar
1506640.01.005
Made in Germany
+
1 2 3
D-32107 Bad Salzuflen
Techn. data
Connection
diagram
Fig.2: Type plate
1.3 Intended use
The DS34 is a differential pressure switch for overpressure, underpressure and
differential pressure measurements. The uncomplicated and robust membrane
measuring mechanism is suitable for all neutral media, such as service water,
heating water, neutral gases and oils.
1.4 Function diagram
1234
5
6
Fig.3: Functional Schematic
1 Micro-switch 2 Switch tappet
3 Diaphragm 4 Measuring range spring
5 Adjustment spindle 6 Pressure chamber
1.5 Design and mode of operation
Due to the pressure or differential pressure to be measured, a one-sided force
acts on the membrane. This force moves the membrane system against the
pre-tensioned measuring range spring. A switch tappet mounted on the mem-
brane actuates a micro switch.
The switch point can be set with an adjustment spindle. A scale plate and a set-
ting mark attached to the housing indicate the respective set switch point.

2 | Assembly and Starting Operation FISCHER Mess- und Regeltechnik GmbH
6/16 BA_EN_DS34
2 Assembly and Starting Operation
2.1 General
The device is intended for installation on flat walls and mounting plates. The
device can be equipped with a mounting foot for screwing to the mounting plate.
2.2 Process connection
• By authorized and qualified specialized personnel only.
• The pipes need to be depressurized when the instrument is being connec-
ted.
• Appropriate steps must be taken to protect the device from pressure surges.
• Check that the device is suitable for the medium being measured.
• Maximum pressures must be observed (cf. Tech. data)
The pressure lines must be installed at an inclination so that when fluids are
measured no air pockets are created or when measuring gases, no water pock-
ets are created. If the required inclination is not reached, water or air filters must
be installed at suitable places.
If water is used as a measuring medium, the unit must be protected against
frost.
The pressure lines must be kept as short as possible and installed without any
tight bends to avoid delays.
Pulsating pressure on the system side can lead to wear and functional prob-
lems. To safeguard this, we recommend installing absorption elements in the
pressure line.
The process connections are marked with (+) and (-) symbols on the device.
The pressure lines must be mounted according to these symbols.
1. Differential pressure measurement
Higher pressure
lower pressure
2. Pressure measurement
Pressure
open
2.3 Electrical connections
• By authorized and qualified specialized personnel only.
• When connecting the unit, the national and international electro-technical
regulations must be observed.
• Disconnect the system from the mains, before electrically connecting the
device.
• Install the consumer-adapted fuses.
• A permanently wired number cable is used for the electrical connection.
Fig.4: Electrical connection

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2.4 Start-up
2.4.1 General
A prerequisite for commissioning is correct installation of all electrical supply
lines and the differential pressure lines. All connections are arranged so that
there are no mechanical forces acting on the device.
CAUTION
Leak test
The differential pressure lines need to be checked for leaks before commission-
ing.
In the case of fluid measuring media, the differential pressure lines must be
vented because different fluid columns in the lines will distort the measure-
ments.
If water is used as a measuring medium, the unit must be protected against
frost.
2.4.2 Switch point setting
The desired switch point is set by turning the scale plate with the adjustment
spindle. The setting mark is then brought into line with the desired value on the
scale.
Scale plate
Setting mark
Adjustment spindle
1 x 5.5 mm
Switch point 035 bar Switch point 0.5 bar
Setting mark
smallest
adjustable value
Fig.5: Switch point setting

3 | Servicing FISCHER Mess- und Regeltechnik GmbH
8/16 BA_EN_DS34
3 Servicing
3.1 Maintenance
The instrument is maintenance-free. We recommend the following regular in-
spection to guarantee reliable operation and a long service life:
• Check the function in combination with downstream components.
• Check the leak-tightness of the pressure connection lines.
• Check the electrical connections.
The exact test cycles need to be adapted to the operating and environmental
conditions. In combination with other devices, the operating instructions for the
other devices also need to be observed.
3.2 Transport
The measuring device must be protected against impacts. It should be transpor-
ted in the original packaging or a suitable transport container.
3.3 Service
All defective or faulty devices should be sent directly to our repair department.
Please coordinate all shipments with our sales department.
WARNING
Process media residues
Process media residues in and ondismantled devices can be a hazard to
people, animals and the environment. Take adequate preventive measures. If
required, the devices must be cleaned thoroughly.
Return the device in the original packaging or a suitable transport container.
3.4 Disposal
Please help to protect the environment by always disposing of the work pieces
and packaging materials in compliance with the valid national waste and recyc-
ling guidelines or reuse them.

FISCHER Mess- und Regeltechnik GmbH Technical data | 4
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4 Technical data
4.1 General
Reference conditions (acc. to IEC 61298-1)
Temperature +15 to +25 °C
Relative humidity 45 … 75 %
Air pressure 86 to 106 kPa 860 to 1060 mbar
Installation position User-defined
4.2 Input variables
Pressure range Adjustment
range
Nominal
pressure
Bursting
pressure
10 … 100% SI unit
0 to 0.6 bar 0.06 to 0.6 bar 6 to 60 kPa PN16 64 bar
0 to 1 bar 0.10 to 1.0 bar 10 to 100 kPa
0 to 1.6 bar 0.16 to 1.6 bar 16 to 160 kPa
0 to 2.5 bar 0.25 to 2.5 bar 25 to 250 kPa
0 to 4 bar 0.40 to 4.0 bar 40 to 400 kPa
0 to 6 bar 0.60 to 6.0 bar 60 to 600 kPa
4.3 Output parameters
Micro-switch AC DC
Max. switching voltage 250 V 30 V
Max. switching current 3 A 0.4 A
Min. switching current 0.1A 0.1A
Max. switching output 250 VA 10 W
Mech. life span 106 switching cycles
4.4 Measuring accuracy
Switching point Adjustment range 10 ... 100 % of the pressure range
Switching point accuracy 3% of the setting range
Hysteresis Switching element (A) 5% of the setting range
Switching element (Z) 12% of the setting range
4.5 Electrical connection
Hard-wired, silicone and halogen-free number cable
Core number 3
Conductor nominal cross-section 0,5 mm2
AWG 21
Outer diameter 6,8 mm

4 | Technical data FISCHER Mess- und Regeltechnik GmbH
10/16 BA_EN_DS34
4.6 Operating conditions
Ambient temperature range -10 to +70 °C
Storage temperature range -10 to +80 °C
Medium temperature range
(for non-freezing media)
-10 to +80 °C
Low-Voltage Directive EN 61010-1:2010 + A1:2019 +
A1:2019/AC:2019
RoHS EN IEC 63000:2018
Protection class IP 65 acc. to EN 60529
Materials of the parts that come into contact with the surroundings
Housing Grivory® GV
Cable screw connection Polyamide
Connection cable Silicone and halogen-free polymer
Mounting foot Stainless steel 1.4301
Materials of the parts that come into contact with the measuring medium
Pressure chamber Grivory® GV
Diaphragm, measuring range spring Stainless steel 1.4310
Adjustment spindle, switch tappet, etc. Brass CW614N (formerly 2.0402)
Seals EPDM
Other parts PTFE
4.7 Construction design
All dimensions in mm unless otherwise stated
Dimension drawing
Fig.6: Dimension drawing

FISCHER Mess- und Regeltechnik GmbH Technical data | 4
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G⅛
Ø15.5
6
19
25
Hose Ø 6/4
Hose Ø 8/6
Fig.7: Pneumatic plug-in connection
Accessories
32
60°
1.5
6
Ø4.2
30°
30 20
5.5
10
18
50
60
Fig.8: Mounting foot

5 | Order codes FISCHER Mess- und Regeltechnik GmbH
12/16 BA_EN_DS34
5 Order codes
F 0
Process connection
Switch elements
Electrical connection
D S 3 4
Type
Setting range
0000
1 2 5 6 7 8 9 10 11 123 4Reference No.
Nominal pressure
Measuring system
[1,2] Setting range Measuring range
AA 0.06 … 0.6 bar 0 … 0.6 bar
AB 0.10 … 1.0 bar 0 … 1 bar
AC 0.16 … 1.6 bar 0 … 1.6 bar
AD 0.25 … 2.5 bar 0 … 2.5 bar
AE 0.40 … 4.0 bar 0 … 4 bar
AF 0.60 … 6.0 bar 0 … 6 bar
[3] Nominal pressure
FPN16
[4] Measuring system
0Standard
[5,6] Process connection
00 Internal thread G⅛
43 Pneumatic plug-in connection for 6/4 mm hose
44 Pneumatic plug-in connection for 8/4 mm hose
[7] Switching contacts
A1 adjustable microswitch
Z1 adjustable microswitch with increased switching hysteresis (12%)
[8] Electrical connection
11.0 m long number cable, hard-wired
22.5 m long number cable, hard-wired
55.0 m long number cable, hard-wired
5.1 Accessories
Art. No. Designation
02006023 Assembly foot

FISCHER Mess- und Regeltechnik GmbH Attachment | 6
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6 Attachment
Fig.9: CE_EN_DS34

6 | Attachment FISCHER Mess- und Regeltechnik GmbH
14/16 BA_EN_DS34
Fig.10: UKCA_EN_DS34

FISCHER Mess- und Regeltechnik GmbH
BA_EN_DS34 15/16
Notes

Mess- und Regeltechnik GmbH
Bielefelder Str. 37a
D-32107 Bad Salzuflen
Tel. [phone]
Fax [phone]
www.fischermesstechnik.de
[email protected]
Technische Änderungen vorbehalten. Subject to technical changes. Sous réserve de modifications techniques.