WIKA DW40, DW100, DA40, DW160, DA100 Instruction Manual

INSTRUCTION MANUAL

NI-209WE

Rev. 8 12/16

DIFFERENTIAL PRESSURE SWITCHES SERIES DA & DW

All data, statements and recommendations supplied with this manual are based on information believed by us to be reliable. As the conditions of

effective use are beyond our control, our products are sold under the condition that the user himself evaluates such conditions before following our
recommendations for the purpose or use foreseen by him.

This document is the property of ALEXANDER WIEGAND SE &Co and may not be reproduced in any form, nor used for any purpose other than
that for which it is supplied.

WEATHERPROOF AND INTRINSICALLY SAFE: MODELS DW

FLAMEPROOF: MODELS DA

Versions: DW40, DW100 e DW160

Versions: DA40, DA100 e DA160

A Low pressure connection
B High pressure connection

C Cable entry V Vents
Weight 6,2 kg (dimensions in mm)

A Low pressure connection
B High pressure connection

C Cable entry V Vents
Weight 7,2 kg (dimensions in mm)

Versions: DW10

Versions: DA10

A Low pressure connection
B High pressure connection

C Cable entry
Weight 8,2 kg (dimensions in mm)

A Low pressure connection
B High pressure connection

C Cable entry
Weight 10 kg (dimensions in mm)

For surface mounting use four screws M6 .

NOTE: dimensions and weights are not binding unless released on certified drawings.
CAUTION

 Before installing, using or carrying out maintenance on the instrument it is necessary to read and understand the indications given in

the attached Instruction Manual.

 The instrument must only be installed and maintained by qualified personnel
 INSTALLATION IS TO BE CARRIED OUT ONLY AFTER CHECKING THAT INSTRUMENT CHARACTERISTICS ARE

CONSISTENT WITH PROCESS AND PLANT REQUIREMENTS.

 The functional features of the instrument and its degree of protection are shown on the identification plate fixed to the case.

CONTENTS:

1. GENERAL NOTES

2. OPERATING PRINCIPLE

3. MODEL CODE

4. IDENTIFICATION PLATE AND MARKINGS

5. SET POINT REGULATION

6. SET POIT CALIBRATION

7. MOUNTING AND CONNECTIONS

8. INSTRUMENT PLUMBING

9. SAFETY INTEGRITY LEVEL (SIL) INSTALLATION REQUIREMENTS

10. PUTTING INTO OPERATION

11. VISUAL INSPECTION

12. FUNCTIONAL VERIFICATION

13. STOPPING AND DISMOUNTING

14. DISPOSAL

15. TROUBLESHOOTING
SAFETY INSTRUCTIONS FOR USE IN HAZARDOUS ATMOSPHERES.
RECOMMENDATIONS FOR PRESSURE SWITCH SAFE USE.

RELATED DOCUMENT

To authenticated document with certificate

N° IECEx PRE 16.0068X
N° IECEx PRE 16.0074X

INSTRUCTION MANUAL

NI-209WE

Rev. 8 12/16

2 of 9

1. GENERAL NOTES

1.1 FOREWORD

The wrong choice of a models or a version, as well as the
incorrect installation, lead to malfunction and reduce instrument
life. Failure to follow the indications given in this manual can
cause damage to the instrument, the environment and persons.

1.2 ALLOWED OVERRANGE

Pressures exceeding the working range can be occasionally
tolerated provided they remain within the limits stated in the
instrument features (vacuum or proof pressure). Continuous
pressures exceeding the working range can be applied to the
instrument, provided they are clearly stated in the instrument
features. The current and voltage values stated in the technical
specifications and ratings must not be exceeded. Transitory
overranges can have a destructive effect on the switch.

1.3 MECHANICAL VIBRATIONS

Can generally lead to the wearing of some parts of the instrument
or cause spurious action. It is therefore recommended that the
instrument be installed in a place where there are no vibrations.
In cases where this is impossible it is advisable to take measures
to lessen the effects (elastic supports, installation with the pin of
the microswitch positioned at right angles to the vibration plane,
etc.).

1.4 TEMPERATURE

Due to the temperature of both the environment and the process
fluid, the temperature of the instrument could exceed the allowed
limits (normally from -40° to +60°C). Therefore, in case it does,
suitable measures (protection against heat radiation, fluid
separators, cooling coils, heated lockers) must be taken. The
process fluid or its impurities must not in any case solidify inside
the instrument chambers

2. OPERATING PRINCIPLE

The differential pressure, acting on the sensitive diaphragm
element, determines its elastic deformation which is used to
actuate one or two electric microswitches adjusted at set point
values. The microswitches are of the snap acting type with
automatic reset. When the pressure moves away from the set
values, returning towards the normal values, the switch is reset.
The dead band (difference between the set point value and the
reset value) can be set or adjustable (letter R in the contact
codes).

3. MODEL CODE

See Annex 1

4. IDENTIFICATION PLATE AND MARKINGS

The instrument is fitted with a metal plate bearing all its functional
characteristics and in case of flameproof or intrinsic safety
execution also the markings prescribed by standard IEC/EN
60079-0. Fig.1 shows the plate mounted on flameproof
instruments.

Fig. 1 - Flameproof instruments plate

1 Notified body that issued the type certificate and number of said

certificate.

2 CE marking and identification number of the notified body

responsible for production surveillance.

3 Apparatus classification according to ATEX 2014/34/EU

directive.

4 Type of protection and ambient temperature limits of operation.

The following table gives the relationship between hazardous
areas, Atex Categories and Equipment Protection Level (EPL)
listed on the flameproof instrument nameplate

Hazardous area

Categories

according to

2014/34/EU

Directive (ATEX)

EPL

Gas, vapours, fog

Zone 0

1G

Ga

Gas, vapours, fog

Zone 1

2G or 1G

Gb or Ga

Gas, vapours, fog

Zone 2

3G, 2G or 1G

Gc, Gb or Ga

Dust

Zone 20

1D

Da

Dust

Zone 21

2D or 1D

Db or Da

Dust

Zone 22

3D, 2D or 1D

Dc, Db or Da

5. SET POINT REGULATION

Each microswitch is independent and can be adjusted by means
of a screw (for adjustment) to snap when the pressure reaches
(increasing or decreasing) the desired value (set point). The
instrument is usually supplied with the switches adjusted at the
setting range value nearest to zero (factory calibration). The
instrument is supplied with a label showing the set point
calibration value. With factory calibration the values are not
indicated, as these are temporary and will be modified with the
definitive values. Prior to installation the instrument must be
calibrated and the definitive calibration values written on the
label.

If the instrument has been ordered with a specific calibration,
check the calibration values marked on the relevant label, prior
to installation.

The position of the adjustment screw is given in figure 2.

Fig. 2 - Electrical connections and adjustment screws

1 - Microswitch 2 set point calibration screw
2 - Microswitch 1 set point calibration screw
3 - Terminal block
4 - Electrical connection identification plate

Microswitch electrical circuit: State of the contacts at atmospheric
pressure

Designation of the contacts:
C - common
NA - Normally open
NC - Normally closed

The effect that the direction of rotation of the adjustment screw
has is described on the label.

6. SET POIT CALIBRATION

In order to proceed with the calibration and the periodical
functional verification of the instrument a suitable calibration
circuit (Fig. 3) and an adequate pressure source is required. The
test instrument should have a measurement range approximately
equal to or slightly wider than the pressure switch range and
should have an accuracy consistent with the accuracy required
to calibrate the set point.

INSTRUCTION MANUAL

NI-209WE

Rev. 8 12/16

3 of 9

Fig. 3 - Calibration circuit

PS - Pressure switch
CA - Test gauge
V1 - Inlet valve
V2 - Discharge valve
P - Pressure source

Test fluid:
air for P < 10 bar
water for P > 10 bar

6.1 PRELIMINARY OPERATIONS

6.1.1Weatherproof pressure switches (Models DW)

Remove the blocking device fixed to the side of the instrument
case and the adjustment screw access plate (Fig. 4). Remove
the cover by rotating it in an anticlockwise direction.

Fig. 4 - Weatherproof pressure switch blocking device

a) Plumbing wire
b) Plumbing
c) Blocking nut

c) Blocking bracket
e) Adjustment screw access
plate

6.1.2Flameproof pressure switches (Models DA)

CAUTION: do not open the cover of flameproof pressure

switches (Models DA) when energized, in explosive
atmospheres.

Loosen the locking headless screw situated on the cover using a
1,5 hexagonal key then unscrew the cover (fig.5). Remove the
internal blocking device inserted on the closure plugs and slide
out the plugs.

Fig. 5 - Flameproof pressure switch blocking device

6.2 CALIBRATION CIRCUIT AND OPERATIONS

Prepare the calibration circuit as indicated in Fig.3.
The warning lamps should be connected to contact 1 or 2 in the
NO or NC position according to the required contact action.

Connection of C and NO terminals

• If the circuit is open at the working pressure, the switch closes
the circuit as the pressure increases when the desired value is
reached.

• If the circuit is closed at the working pressure, the switch opens
the circuit as the pressure decreases when the desired value is
reached.

Connection of C and NC terminals

• If the circuit is closed at the working pressure, the switch opens
the circuit as the pressure increases when the desired value is
reached.

• If the circuit is open at the working pressure, the switch closes
the circuit as the pressure decreases when the desired value is
reached.
The pressure switch must be mounted in the normal installation
position, i.e. with the pressure connection pointing downwards.
Avoid forcing the elastic support of the microswitch by hand or
with tools. This could affect the instrument functioning.

CAUTION: if the switch is of the kind with adjustable dead band
(letter R in the contact codes) before proceeding with the
following operations it is necessary to proceed with the
adjustment of the dead band.

Increase the pressure in the circuit up to the desired set point
value for the first microswitch. Use a wide bladed screwdriver, as
indicated on the label, turn the screw until the relative lamp turns
on (or turns off).

- If the instrument is equipped with only one contact the
calibration is complete.

- If it is equipped with two contacts continue in the following
manner. Vary the pressure until the desired set point value for
the second microswitch is reached. Act on the adjustment screw
of the second contact.
Repeat calibrating operations on the first contact, then on the
second contact, until the required set point accuracy is obtained.
This is necessary due to the reciprocal influence which the
microswitches have on the sensitive element of the instrument.

CAUTION: if the two set point are different they must be different
for much of 5% of the adjustable span.

6.3 CHECK OF SET POINT

Generate the normal working pressure and wait the pressure
stabilisation. Vary the pressure into the circuit and record the set
point value. Write the set point values on the adhesive label.
Note: the repeatability should be checked verifying for three
times the set point (Pi) starting always from the same pressure
value (Pw). The pressure cycle should be slowly to give the
possibility to record the set point with accuracy.

6.4 CALIBRATION CIRCUIT FOR INSTRUMENT WITH
ADJUSTABLE RANGE LESS TO 60 mbar

The calibration circuit used for the calibration of these
instruments must be:

- of big internal volume (5 liters or bigger) in order to reduce the
effect of volumetric variation (and therefore of pressure) caused
by the sensing element of the pressure switch during the snap
action.

- in a thermally stable place in order to guarantee stability to the
pressure inside the circuit used for the calibration.
Have to be considered that in a closed circuit with the internal
pressure equal to the atmospheric pressure, the variation of
temperature of 1°C causes in the circuit a pressure variation of
3,4 mbar.
The maximum inlet pressure must not exceed the lesser of
overpressure allowed by the pressure switch and the test gauge.
The test instrument should have a measurement range
approximately equal to or slightly wider than the pressure switch
range and should have an accuracy consistent with the accuracy
required to calibrate the set point.
For example DW10 range 0..16mbar the accuracy of the test
gauge must be ± 0,04 mbar to calibrate the set point with an
accuracy of ± 0,16 mbar (1% of the adjustable span).