WIKA DA10 User Manual

NI-209E

INSTRUCTION MANUAL

Rev. 4 12/02

DIFFERENTIAL PRESSURE SWITCHES

WEATHERPROOF: SERIES DW EXPLOSIONPROOF: SERIES DA

Models DW40, DW100, DW160

Models DA40, DA100, DA160

C

C

AB

AB

A Low pressure attachment
B High pressure attachment

Weight 6,2 kg dimensions in mm Weight 7,2 kg dimensions in mm
Models DW10

C

C Cable entry

A Low pressure attachment
B High pressure attachment

Models DA10

C

C Cable entry

AB

A Low pressure attachment
B High pressure attachment
Weight 8,2 kg dimensions in mm Weight 10 kg dimensions in mm

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.

SAFETY INSTRUCTIONS FOR USE IN HAZARDOUS ATMOSPHERES.

RECOMMENDATIONS FOR PRESSURE SWITCH SAFE USE.

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.

The present document is the property of ETTORE CELLA SPA and may not be reproduced in any form, nor used for any
purpose other than that for which it is supplied.

C Cable entry

A Low pressure attachment
B High pressure attachment

AB

C Cable entry

RELATED DOCUMENT

To authentified document with certificate

N° CESI 03 ATEX 004

INSTRUCTION MANUAL

1. GENERAL NOTES

1.1 FOREWORD

The wrong choice of a series or a model, 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 false actuation. 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 -20° to +70°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 regulated 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).

NI-209E

Rev. 4 12/02

3. IDENTIFICATION PLATE AND MARKINGS

The instrument is fitted with a metal plate bearing all its
functional characteristics and – in case of
explosionproof execution (Series DA) – also the
markings prescribed by standard CEI EN 50014. Fig. 1
shows the plate mounted on explosionproof instruments.

Fig. 1 - Explosionproof instruments plate

1 CE marking and identification number of the notified body

responsible for production surveillance.

2 Apparatus classification according to ATEX 94/9 CE

directive.

3 Type of protection and ambient temperature limits of

operation.

4 Notified body that issued the type certificate and number of

said certificate.

4. SET POINT REGULATION

Each microswitch is independent and can be regulated
by means of a screw (for adjustment) in such a way that
it is released when the pressure reaches (increasing or
decreasing) the desired value (set point).
The instrument is usually supplied with the switches set
at the setting range value nearest to zero (factory
calibration).
The instrument is supplied with an adhesive rating plate
showing the set point calibration value. With factory
calibration the values are not indicated on the ratings
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
adhesive rating plate using a suitable indelible ink pen.

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

The position of the adjustment screws is given in fig. 2.
The effect that the direction of rotation of the adjustment
screws has is described on the adhesive plate.

INSTRUCTION MANUAL

Fig. 2 - Electrical connections and adjustment screws

One contact instruments Two contact instruments

NI-209E

Rev. 4 12/02

Microswitch electrical circuit:
State of the contacts at
atmospheric pressure

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

5. SET POINT CALIBRATION

In order to proceed with the calibration and the
periodical functional verification of the instrument a
suitable calibration circuit (fig. 5) and an adequate
pressure source is required.

5.1 PRELIMINARY OPERATIONS

Weatherproof pressure switches (Series DW) (Fig.

3)

Remove the blocking device fixed to the side of the
instrument case and the adjustment screw access plate.
Remove the cover be rotating it anticlockwise.

Fig. 3 -

and plumbing

Weatherproof pressure switch cover blocking device

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

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

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

Fig. 4 -

Explosionproof pressure switch cover blocking device

a) Plumbing wire
b) Plumbing
c) Blocking nut

Explosionproof pressure switches (Series DA) (Fig.

4)

CAUTION: do not open the cover of explosionproof

pressure switches (Series DA) when energized, in
explosive atmospheres.

c) Blocking bracket
e) Adjustment screw access
plate

5.2 CALIBRATION CIRCUIT AND OPERATIONS

Prepare the control circuit as indicated in Fig.5.
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.