WIKA 891.34 User manual

Testing Instructions
Prüfanleitung
Instructions de vérification
Instrucciones
GB
D
F
E
Pressure Gauges
Mechanische Druckmessgeräte
Manomètres mécaniques
Manómetros mecánicos
Examples/Beispiele/Exemples/Ejemplos

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WIKA Testing Instructions for Pressure Gauges
Testing Instructions for Pressure Gauges Page 3-8
Prüfanleitung für mechanische Druckmessgeräte Seite 9-14
Instructions de vérification pour Manomètres mécaniques Page 15-20
Instrucciones para Manómetros mecánicos Página 21-26

1. Safety instructions 4
2. Testing the display 4
2.1 Process for display testing 5
3. Testing of switch contacts 6
4. Testing for transmitters 8
5. Repairs 8
WIKA Testing Instructions for Pressure Gauges 3
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Contents
Contents

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Caution
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1. Safety instructions / 2. Testing the display
1. Safety instructions
The appropriate national safety regulations (i.e. VDE 0100 /
EN 837-2) must be observed when installing, commissioning and
operating these instruments.
Only appropriately qualified personnel should work on these instruments
Pressure gauges may only be removed once they are free from pressure
Any residual pressure medium contained in the pressure element may be
hazardous or toxic. This should be taken into account when handling and
storing pressure gauges which have been removed.
Serious injuries and/or damage can occur should the appropriate regulations
not be observed
2. Testing the display
Basic testing principles
The accuracy class is tested in accordance with EN 837
The display is always tested in accordance with the operational error limit
The test is carried out with rising and falling pressure. With gauges that have
a free zero point the lower limit and the upper limit of the scale range are
used as the measuring points.
The pressure gauge used as a measuring standard must be at least four
times as accurate as the device to be tested:
e.g.: Device under test = Class 1.6 ⇒Test variable ≤Class 0.25
The measured values indicated are recorded after gently knocking on the
case
For pressure gauges with electrical alarm contacts, the set point indicator(s)
should be set so that any load on the actual value pointer is eliminated as
far as possible. The test of the scale range when the alarm contacts are
change-over contacts is carried out with the contacts at 12 o‘clock (both
contact arms load the actual value pointer).
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Examples of the calculation of the permissible deviation
(linearity and hysteresis):
Scale range: 0 ... 10 bar (measuring span = 10 bar)
Class 1.6 (error limit = 1.6 %)
Permissible deviation: = ± 0.16 bar
Scale range: -1 ... +25 bar (measuring span = 26 bar)
Class 1.0 (error limit = 1.0 %)
Permissible deviation: = ± 0,26 bar
2.1 Process for display testing
The accuracy class is always determined at the reference standard, i.e. the
measuring point to be tested must be generated at the test specimen and the
deviation of the value measured at the measuring point is to be recorded from
at the reference standard.
The following test features must always be tested prior to the actual display
testing:
Pointer movement (smooth)
Zero error (after running through the entire scale range)
Static pressure test (differential pressure gauges) with a pressure load of the
max. overload capacity:
The zero error must not exceed the operational error limit.
Free movement of the pointer beyond the upper limit of the scale range,
however up to a max. of the 6 o'clock position.
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2. Testing the display
Pressure gauge
Class
Error limit Number of measuring
points
0.1 0.1 % at least 10
0.2 0.2 % at least 10
0.3 0.3 % at least 10
0.6 0.6 % at least 10
1.0 1.0 % at least 5
1.6 1.6 % at least 5
2.5 2.5 % at least 5
4.0 4.0 % at least 5
Error limits for the display (per EN 873-1 / EN 837-3)
10 x 1.6
100
26 x 1.0
100

1. 2.
3. 4.
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3. Testing of switch contacts
Basic testing principles
The correct pin assignment and the permissible contact rating must be taken
from the product label on the exterior of the housing.
Versions
Switch contacts are classified as follows:
Sliding contacts Model 811
Magnetic snap-action contacts Model 821
Inductive contacts Model 831
Fail-safe inductive contacts Model 831 SN and 831 S1N
(special designs)
The design and construction of these switch contacts and their function are
described in Data Sheet AC 08.01 "Electrical Switch Contacts".
Contact function index
The contact function is indicated in the clockwise direction of the instrument
pointer rotation. The contact function is indicated by a code to the right of the
full stop which follows the respective model code, e.g. 821.2. The contact type
(single - double - triple contact) can be seen from the number of indices which
follow the corresponding model code, e.g. 821.212 = triple inductive contact.
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2. Testing of the display / 3. Testing of the switch contacts
Examples of the measured value registration:
Scale: 0 ... 10 bar Scale: -1 bar ... +10 bar
Measu- Rising Falling Measu- Rising Falling
ring point pressure pressure ring point pressure pressure
1. 0 bar 0 bar 8. -1 bar -1 bar
2. 2 bar 2 bar 7. -0.5 bar -0.5 bar
3. 4 bar 4 bar 1. 0 bar 0 bar
4. 6 bar 6 bar 2. 2 bar 2 bar
5. 8 bar 8 bar 3. 4 bar 4 bar
6. 10 bar 10 bar 4. 6 bar 6 bar
5. 8 bar 8 bar
6. 10 bar 10 bar

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Meaning of the codes
Index 1: Contact makes when the instrument pointer approaches
the set point in a clockwise direction ⇒NO contact
Index 2: Contact breaks when the instrument pointer approaches
the set point in a clockwise direction ⇒NC contact
Index 3: Contact breaks one circuit and makes a second circuit when the
instrument pointer approaches the set point in clockwise
direction ⇒SPDT contact. (not with Model 831)
Example of the contact model, contact type and function index
Model 821. 21 2 means:
821. = Magnetic snap-action contact
21 2 = Triple inductive contact (because of 3 digits)
2 = 1st contact breaks when pointer reaches set point (NC)
1 = 2nd contact makes when pointer reaches set point (NO)
2 = 3rd contact breaks when pointer reaches set point (NC)
Contact accuracy
The accuracy of the contacts is tested in accordance with EN 837 and DIN
16 085. The contacts are generally tested in ranges of 25 %, 50 % and 75 %
of the full scale value, provided that no other values or switching points are
specified.
Error limits
The deviation of the switching point from the set limit value must not exceed
the 1.5-fold value of the error limit of the pressure gauge.
The switching hysteresis may be:
With sliding contacts: max. 1 %
With magnetic snap-action contacts: between 2 % and 5 %
With inductive contacts: max. 1 %
of the measuring span.
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3. Testing of switch contacts

10 x 1.6
100
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WIKA Testing Instructions for Pressure Gauges
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4. Testing for transmitters / 5. Repairs
4. Testing for transmitters
Transmitter versions
Standard Model 891.34
Ex-version Model 892.34
The design and construction of the transmitters and their function is described
in Data Sheet AC 08.02 "Transmitters to combine with pressure gauges" and
the operating instructions are included with the instrument.
Connection details
2-wire 4 ... 20 mA
Clip 1: Earth power supply / earth signal
Clip 2: Power supply 10 ... 30 V / plus signal
Clip 3: Test minus
Clip 4: Test plus
3-wire 0 ... 20 mA
Clip 1: Earth power supply / earth signal
Clip 2: Power supply 14 ... 30 V
Clip 3: Test plus
Clip 4: Signal plus / test minus
Accuracy of the output signal
The accuracy of the output signal is stated with reference to the measuring
span, e.g.:
Output signal: 0 ... 20 mA Measuring span: 20 mA
Output signal: 4 ... 20 mA Measuring span: 16 mA
For the permissible error limits the accuracy class of the base instrument
applies, e.g.:
Base instrument: Class 1.5 Permissible deviation: ±1.6 %
Output signal: 4 ... 20 mA Measuring span: 16 mA
Permissible deviation of the output signal: = ± 0.256 mA
Please note:
With regard to the measuring error the transmitter should always to be consi-
dered separately, i.e. the measurement error of the output signal must always
be separately tested in comparison with the reference standard.
5. Repairs
Repairs are only to be carried out by the manufacturer or appropriately trained
personnel.
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1. Sicherheitshinweise 10
2. Prüfung der Anzeige 10
2.1 Ablauf der Anzeigeprüfung 11
3. Prüfung des Schaltkontaktes 12
4. Prüfung bei Ferngebern 14
5. Reparaturen 14
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WIKA Prüfanleitung für mechanische Druckmessgeräte
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Inhalt
Inhalt

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Vorsicht
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WIKA Prüfanleitung für mechanische Druckmessgeräte
10
D
1. Sicherheitshinweise / 2. Prüfung der Anzeige
1. Sicherheitshinweise
Beachten Sie unbedingt bei Montage, Inbetriebnahme, Betrieb und
Demontage dieser Geräte die entsprechenden nationalen Sicher-
heitsvorschriften (z. B. VDE 0100 / EN 837-2).
Nur entsprechend qualifiziertes Personal darf an diesen Geräten arbeiten
Druckmessgeräte nur im drucklosen Zustand demontieren
Messstoffreste in ausgebauten Druckmessgeräten können zur Gefährdung
von Menschen, Umwelt und Einrichtung führen.
Ausreichende Vorsichtsmaßnahmen sind zu ergreifen.
Bei Nichtbeachten der entsprechenden Vorschriften können schwere Körper-
verletzungen und / oder Sachschäden auftreten
2. Prüfung der Anzeige
Arbeitsgrundsätze
Prüfung der Anzeigegenauigkeit erfolgt nach EN 837
Prüfung der Anzeige erfolgt immer nach Verkehrsfehlergrenze
Prüfung erfolgt bei steigenden und bei fallenden Druck. Anfang und Ende
der Skale sind Messpunkte bei Geräten mit freiem Nullpunkt
Für die Prüfung muss als Normal ein Druckmessgerät verwendet werden,
dessen Messgenauigkeit mindestens viermal besser ist als die des zu
prüfenden Gerätes
z. B.: Prüfling = Klasse 1,6 ⇒Prüfnormal ≤Klasse 0,25
Die angezeigten Messwerte werden nach leichtem Klopfen am Gehäuse
abgelesen
Bei Druckmessgeräten mit elektrischen Grenzsignalgebern ist der/die
Sollwertzeiger so zu stellen, dass eine Belastung des Istwertzeigers
möglichst ausgeschlossen ist.
Die Prüfung des Anzeigebereiches mit Grenzsignalgebern als Wechsler
erfolgt bei Wechslerstellung 12 Uhr (beide Kontaktarme belasten den
Istwertzeiger).
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