NI-223E
INSTRUCTION MANUAL
COMPACT DIFF. PRESSURE SWITCHES SERIES DC & DE
WEATHERPROOF EXPLOSIONPROOF
SERIES DC SERIES DE
Rev. 2 11/02
Sfiati
vents
A High pressure connection
B Low pressure connection
WEIGHT 5,4 kg dimensions in mm WEIGHT 5,4 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.
CONTENUTO
1 - GENERAL NOTES
2 - OPERATING PRINCIPLE
3 - IDENTIFICATION PLATE AND MARKINGS
4 - SET POINT REGULATION
5 - SET POINT CALIBRATION
6 - MOUNTING AND CONNECTIONS
7 - INSTRUMENT PLUMBING
8 - PUTTING INTO OPERATION
9 - FUNCTIONAL VERIFICATION
10 - TROUBLESHOOTING
11 - STOPPING AND DISMOUNTING
12 - DEMOLITION
SAFETY INSTRUCTIONS FOR USE IN HAZARDOUS ATMOSPHERES.
RECOMMENDATIONS FOR PRESSURE SWITCH SAFE USE.
C Cable entry A High pressure connection
B Low pressure connection
RELATED DOCUMENT
To authentified document with certificate
N° CESI 02 ATEX 119
Sfiati
vents
C Cable entry
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.
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
Differential pressure exceeding the working range can be occasionally tolerated provided they remain within the limits stated in
the instrument features (vacuum or proof pressure). Continuous
differential pressure 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
over-ranges 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 -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 simultaneous release electric microswitches. 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.
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
DE) – also the markings prescribed by standard CEI EN 50014.
Fig. 1 shows the plate mounted on explosionproof instruments.
NI-223E
Rev. 2 11/02
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 direc-
tive.
3 Type of protection and ambient temperature limits of opera-
tion.
4 Notified body that issued the type certificate and number of
said certificate.
4 - SET POINT REGULATION
Adjustment is made by turning a screw that makes the
switch/switches activate when the pressure (increasing or decreasing) reaches 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 cali-
brated 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 adjustment screw (fig.2) , which acts on the switch, is part of
the transmission system for shifting the sensor element. The adjustment must therefore be made very carefully. To facilitate the
calibration operation (§ 5.2) , its seat is provided with a graduated
scale; each increment of this scale equals approximately 5% of
the full range of the differential pressure switch. Therefore, using
the slot on the top of the adjustment screw as a reference, the
screw can be turned to obtain a certain value.
The effect that the direction of rotation of the adjustment screws
has is described on the adhesive plate.
Fig. 2 - Electrical connections and adjustament screws with one or two contacts instruments
INSTRUCTION MANUAL
1 - Adjustment screw
2 - Screw for fixing the adjustement
3 - Terminal block for the first microswitch
4 - Hole for test plug
5 - Terminal block for the first microswitch
6 - Internal earth screw
7 - Pre-insulated thimbles
8 - External earth screw
9 - Adjustment bush access plate
10 - Graduated dial
Microswitch electrical circuit.
State of the contacts at atmospheric pressure
NI-223E
Rev. 2 11/02
≅ 5% span
5 - SET POINT CALIBRATION
In order to proceed with the calibration and the periodical functional verification of the instrument a suitable calibration circuit
(fig.4) and an adequate pressure source is required.
5.1 PRELIMINARY OPERATIONS
CAUTION: do not open the cover of explosionproof pressure
switches (Series DE) when energized, in explosive atmospheres.
With reference to fig.3 unscrew the screw (b) until the blocking
device (a) can be turned 180°; then unscrew the cover.
Fig. 3 - Cover blocking device and plumbing
Designation of the contacts:
C – Common
NA – Normaly open
NC – Normaly closed
plug with a diameter of 2 mm to be inserted in the appropriate
holes situated frontally beside the terminal screw (see fig.2).
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 values is
reached (MAKE on Raise).
• If the circuit is closed at the working pressure, the switch opens
the circuit as the pressure decreases when the desired value is
reached (BREAK on Fall).
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 (BREAK on Raise).
• If the circuit is open at the working pressure, the switch closes
the circuit as the pressure decreases when the desired value is
reached (MAKE on Fall).
The test instrument should have a measurement range approximately equal to or slightly wider than the differential pressure
switch range and should have an accuracy consistent with the
precision required to calibrate the set point.
The differential pressure switch must be mounted in the normal
installation position, i.e. with the pressure connections downwards.
Fig. 4 - Calibration circuit
a - Cover blocking device
b - Blocking screw
c - Screw blocking the adjustment bush access plate
d - Flexible steel wire
e - Plumbing
f - Adjustment bush access plate
5.2 CALIBRATION CIRCUIT AND OPERATIONS
Prepare the control circuit as indicated in Fig. 3 by connecting the
+ (or H) port to the pressure source and leaving the - (or L) port
open to the atmosphere.
The warning lamps should be connected to the contacts in the
NA or NC (NA = Normally Open NC = Normally Closed) position
according to the required contact action.
If the instrument is equipped with two microswitches, take into
account that they actuate simultaneously within rated tolerances.
The warning lamps can either be connected by means of a thimble with a maximum diameter of 2.5 mm or by means of a test
DPS Differential pressure switches Test fluid:
CA Test gauge air for P ≤ 10 bar
V1 Inlet valve water for P > 10 bar
V2 Discharge valve
P Pressure source
Avoid forcing the microswitch by hand or with tools. This could affect the instrument functioning.
With reference to fig.3, clear the access to the adjustment bush
by loosening the screw (c) which holds the access plate (f).
Increase gradually pressure in the circuit up to the desired microswitch set point value (P
If the switch activates during the aforesaid operation, turn the adjustment screw in the + direction until the switch activates again.
If it does not activate, rotate the adjustment screw in the - direction until the switch activates.
Raise the circuit pressure to the normal working value.
Slowly return to the intervention pressure until the indicator lamp
turns on (or off), and note the pressure value (P
Calculate the difference between the set and noted pressure values (P
Calculate what percent the difference D is of the full differential
pressure range.
Annul the pressure difference, D, by turning the adjustment screw
the appropriate amount and in the appropriate direction, using the
graduated scale as a reference (§ 4 and fig.2).
Check the pressure calibration value by appropriately varying the
circuit pressure. Note this value on the adhesive label using an
indelible ink pen.
Example: Instrument with 0-1 bar range.
Desired set point value: 400 mbar
Read set point: 415 mbar
Difference: D = 400-415 = - 15 mbar
Correction: Turn the adjustment screw in the pressure-reducing
direction a distance equal to 1/3 of the full-scale reading of the
graduated scale.
i – Pr
= D).
).
i
INSTRUCTION MANUAL
).
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5.3 FINAL OPERATIONS
Disconnect the instrument from the calibration circuit.
With reference to fig.2 close the access to the adjustment bush
by rotating the access plate (9) and tighten the relative screw (2).
Take the cover, ensure that the sealing gasket is correctly fitted
into its seat, insert the cover onto the case and turn it clockwise
until the cover is closed. With reference to fig.3 turn the blocking
device (a) 180° sliding the tongue into the appropriate seat in the
cover; then tighten the blocking screw (b).
Mount on pressure connections and cable entry the protection
caps supplied with the instrument. The protection caps should
only be definitively removed during the connection steps (see §
7).
6 - INSTRUMENT PLUMBING
With reference to fig. 3 the plumbing, aimed as a guarantee
against possible tampering of the calibration, can be carried out
using a flexible steel wire (d) inserted into the holes in the screw
(c) and the adjustment bush access plate (f) provided for this
purpose.
7 - MOUNTING AND CONNECTIONS
NI-223E
Rev. 2 11/02
Carry out the connection using a flexible tube in such a way that
variations in the temperature of the tube itself do not force the instrument connections.
Ensure that all the pressure connections are airtight. It is important that there are no leakage in the circuit.
Close root valves, the two service valves, drain plugs and open
the by-pass valve.
NOTE: if the instrument is used for level control in tanks under
pressure it is recommended that installation is carried out according to the diagram in fig.9; ensuring that
• the distance K is greater than 0,5 m
• the seal pot B has a sufficient capacity to maintain the liquid
level at the maximum height over time.
7.3 ELECTRICAL CONNECTIONS
It is recommended to carry out the electrical connections according to the applicable standards. In case of explosionproof instruments (Series DE) see also the Standard EN-60079-14. If the
electrical connection is carried out in a protected tube, it shall be
made so that condensate is prevented from entering instrument
enclosure.
The arrangement shown in fig. 6 or 7 is therefore recommended.
WARNING: the cable entry not used must be plugged and
sealed using the plug supplied with the instrument, in order to
prevent rain water or other liquids from entering the enclosure.
Should the enclosure be explosionproof the EEx-d degree of protection is NOT guaranteed unless the plug is correctly mounted
and blocked in such a way that it cannot be removed. Furthermore, in order to guarantee the degree of protection IP65 and
the unlocking of the blocking joint or cable gland from the enclosure, the coupling thread must be sealed with the same anaerobic sealing used for the plug on the unused cable entry (e.g.: Loctite ® 648)
7.1 MOUNTING
Surface mount the instrument by means of the holes provided, or
pipe mount using the appropriate bracket (see fig.8). The chosen
position must be such that vibrations, the possibility of shocks or
temperature changes are within tolerable limits. With gas or vapour process fluid, the instrument must be positioned higher than
the pipe inlet (see fig. 7). With a liquid process fluid, the instrument can be positioned higher or lower, indifferently (see fig.6
and 7).
7.2 PRESSURE CONNECTIONS
Connecting lines are an integral part of the instrument in transmitting the measured variable from the measuring point to the instrument.
For a correct installation it is necessary to:
Mount a shut-off valve with drain (root valve) on each process
pipe inlet to allow the instrument to be excluded and the connection tubing to be drained. It is recommended that said valve has a
capstan blocking device aimed at preventing it being activated
casually and without authorisation.
Mount a 3 valve manifold near the instrument to permit possible
functional verification on site and removal of the instrument. It is
recommended that the manifold is made up of two service valves,
one by-pass valve and two suitably connected drain plugs.
Mount a three piece joint onto the threaded connections of the instrument to permit the easy mounting or removal of the instrument itself.
INSTRUCTION MANUAL
CAUTION: fittings used for the electrical connection of the
pressure switch Series DE (explosionproof) shall be certified to
Standards EN 50014 and 50018, and shall guarantee instrument
degree of protection (IP65).
Check that there is no power in the lines.
Remove the cover and carry out the cabling and connections to
the terminal block (see fig.2). Flexible cables with a maximum
section of 1,2 mm
insulated thimbles with a maximum diameter of 2,5 mm supplied
with the instrument.
When inserting cables into the enclosure pay attention not to
force the microawitch with cable or tools, otherwise instrument
calibration or even its operation could be compromised. The microswitch has been factory mounted and positioned in order to
obtain the best performances. Any tampering made on site without following instructions authorised by the E. CELLA SPA may
result in instrument malfunction.
Ensure that no deposits or wire ends remain inside the case.
Once the connection operations have been completed, replace
the cover and ensure that it is properly sealed and blocked (see
fig. 3).
7.4 SPECIAL NOTE FOR INSTALLATION OF
CATEGORY 1 / 2 G PRESSURE SWITCHES
Explosionproof pressure switches (Series DE) can be installed on
processes requiring apparatus of group II category 1 in an ambient requiring apparatus of group II category 2 (see Fig. 5).
Fig. 5 - Installation of Group II Cat. 1 / 2 G instruments
2
(16AWG) are recommended using the pre-
NI-223E
Rev. 2 11/02
8 - PUTTING INTO OPERATION
As the signal transmitted by the instrument is used in a complex
system, it is necessary that the means of putting it into operation
are established by personnel in charge of the plant.
The instrument comes into operation as soon as the root valves
are opened and then, afterwards, the service valve attached to
the instrument + inlet pipe is opened, the by-pass valve closed
and the service valve attached to the instrument - inlet pipe is
opened. Any possible drainage of the connection tubing can be
carried out by opening the drains fitted the instrument.
In case of explosionproof instruments (Series DE), initial inspections are to be carried out according to customer procedures and
at least in accordance with Standard EN-60079-17.
NOTE: : if the instrument is used for level control in tanks under
pressure and is installed according to the diagram in fig.9 proceed as follows. Close the root valves V1 and V2 open the valves
V3 V4 V5 (the service and by-pass valves). Fill with the process
fluid, from plug SB positioned on the seal pot B, bleeding air from
the plug S positioned on the seal pot near the V2 valve. Then
close S and top up the liquid in B. Remove air from the breather
plug S+ and S- positioned on the instrument, topping up the liquid
in B. Close the plug SB and the by-pass valve V5 and open the
root valves V1 and V2. The instrument is ready for use.
9 - FUNCTIONAL VERIFICATION
This will be carried out according to the Client’s control procedures. Series DC instruments can be verified on the plant if installed as illustrated in fig.6 or 7.
The instruments Series DE may be checked on site only if
apparatus suitable for explosive atmosphere are used and
provided that the electric line is not energized
If this is not the case it is necessary to stop operation, dismount
by means of the three piece joints and carry out the verification in
a test room.
CAUTION: do not open the cover of explosionproof pressure
switches (Series DE) when energized, in explosive atmospheres.
Verification consists in checking the calibration value and possibly regulating the adjustment screw (see par.5).
In case of explosionproof instruments (Series DA), inspections of
the electrical installation are to be carried out also according to
customer procedures and at least in accordance with Standard
EN-60079-17.
NI-223E
INSTRUCTION MANUAL
10 - TROUBLESHOOTING
IMPORTANT NOTE: operations involving replacement of essential components must be carried out at our workshop, especially
for instruments with explosionproof certificate; this is to guarantee the user the total and correct restoration of the product
original characteristics..
MALFUNCTION PROBABLE CAUSE REMEDY
Air bubbles in the connection lines (condensa-tion in the
case of use of gas).
Solid particles deposited inside the measure-ment cham-
bers of the instrument.
Set point shift
Slow response
No actuation or
undue actuation
Undue actuation
Permanent deformation of the sensitive element due to
fatigue or non-tolerated over-ranges.
Variation of the elastic features of the sensitive element
due to its chemical corrosion.
Leakage of filling fluid.
Clogged or obstructed connection line.
Root or service valve partially closed
Too viscous fluid.
Root or service valve closed.
By-pass valve open.
Microswitch contacts damaged.
Loosened electrical joints.
Interrupted or short-circuited electrical line.
Accidental shocks or excessive mechanical vibrations. Modify the mounting.
11 - STOPPING AND DISMOUNTING
Before proceeding with these operations ensure that the plant or
machines have been put into the conditions foreseen to allow
these operations.
With reference to figures 6 and 7
Remove the power supply (signal) from the electrical line.
Close the service valve (2) and open the by-pass valve.
Carefully open the drains.
Do not dispose of the process fluid into the environment, if this
can cause pollution or damage to people.
Unscrew the three piece joint (1).
CAUTION: do not open the cover of explosionproof pressure
switches (Series DE) when energized, in explosive atmospheres.
Unscrew the three piece joint (11) (electrical cable tubing).
Remove the instrument cover and disconnect the electrical cables from the terminal block and earth screws. Remove the
screws fixing the case to the panel (or pipe) and remove the instrument, taking care to slide the electrical conductors out from
the case.
Mount instrument cover. Insulate and protect cables around, if
any. Temporarily plug pipes not connected to the instrument. In
case of explosionproof instruments (Series DE) it is recommended to follow - at least – the standard EN-60079-17 for the
withdrawal from service of electrical apparatus.
12 - DEMOLITION
The instruments are mainly made of stainless steel and aluminium and therefore, once the electrical parts have been dismounted and the parts coming into contact with fluids which could
be harmful to people or the environment have been properly dealt
with, they can be scrapped.
Drain using the appropriate plugs.
Dismount the measurement chambers and
clean them (during the mounting phase the
screw locking couple is 80 N•m).
Recalibrate or replace the sensitive element.
Recalibrate or replace the sensitive element
with another made of a suitable material. If
necessary apply a fluid separator.
Send to the manufacturer for checking.
Check and clean line.
Open valve.
Provide instrument with suitable fluid separator
(Return to the manufacturer).
Open the valve.
Close the valve.
Replace the microswitch.
Check all electrical joints.
Check the conditions of the electrical line.
Rev. 2 11/02
WEATHERPROOF EXPLOSIONPROOF
Fig. 6 - Example of connections
INSTRUCTION MANUAL
Fig. 7 - Example of connections
NI-223E
Rev. 2 11/02
Fig. 8 - Example of mounting -
Surface mounting
Montaggio a parete
2” pipe mounting
Montaggio su palina
1 - Three piece fitting
2 - Three valve manifold
3 - Three piece fitting
4 - Piping
5 - Three piece fitting
NOTE With gas or vapour process fluid, the instrument must be positioned higher than the pipe inlet (see fig.7). With a liquid process fluid, the instrument can be positioned higher or lower, indifferently (see fig.6 and 7)
6 - Root valve with drain
7 - Filter or nozzle
8 - Check inlet and drain plug
9 - Blocking joint
10 - Curve
Fig. 9 - Level check of tanks under pressure –
11 - Three piece fitting
12 - M6 screws (No. 4)
13 - Bracket for 2" pipe
14 - Vertical pipe
15 - Horizontal pipe
ETTORE CELLA SPA Viale de Gasperi, 48 - Casella Postale (P.O. Box) 96 - I 20010 Bareggio (MILANO) ITALY
Telefoni +39 029036.1146/1237/1241 - FAX +39 029036.1331 e-mail: cella@ecellaspa.com
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