Instrument Plumbing; Safety Integrity Level (Sil) Installation Requirements - WIKA mw series Instruction Manual

CAUTION: fittings used for the electrical connection of the flame-
proof instruments shall be certified according the IEC or EN stand-
ards and shall guarantee instrument degree of protection (IP66).
In the case of Gk threads, this is made in accordance with standard
UNI-EN 60079-1 (Italian national variant).
It is recommended the installation according Fig. 21 o 22.
The installation of the cable gland or three-piece joint should be as
per fig. 10 and 11.
Fig. 10 – Installation of electrical connection
With the instrument into the final position provided that the electric
line is not energize, remove the cover and make the electrical
connection to the terminal block (see Fig. 2).
If the ambient temperature exceeds 60 °C is recommended to use
cables suitable for operating temperatures of at least 105 °C.
Flexible cables with a maximum section of 1,5 mm
recommended using the pre-insulated crimp ring terminal.
Do not touch the adjustment screws and do not bend the elas-
tic microswitch supports in order to prevent the instrument calibra-
tion being altered. Ensure that no deposits or wire ends remain
inside the case.
Warning: The instrument may be equipped with one or two micro
switches SPDT type. All the electrical connection must be part of
intrinsically safe circuits. The relevant parameters for intrinsic
safety are listed on the nameplate of the instrument.
The tightening of the cable gland or the three-piece joint must be
performed as shown in Fig. 11
Fig. 11 – Installation of the cable gland
As soon as connection steps are completed, mount the cover on
and make sure it is tight and blocked See fig 4 and 5.
7.5.1
CONNETTOR 7 POLES TYPE MIL-5015 FOR WEATHER
PROOF INSTRUMENT
The free connector, supplied with the instrument, is able to accept
multicore cables with maximum outer diameter 11 mm. It is recom-
mended flexible cables with single-conductor with a maximum sec-
tion of 1.5 mm2 (16AWG).
The cable have to be prepared as per fig. 12
Fig. 12 – Cable preparation
The single stripped conductor has to be crimped with each contact
pin. For the electrical connections and for the assembly follow
Fig.13.
INSTRUCTION MANUAL
2 (16AWG) are
A= 53mm
B= 30mm
C= 6,5 mm
Fig. 13 – Free connector assembly
1- Cable
2- Heat Shrink Boot
3- Clamp
4- Extender
The wiring diagram is according Fig.14.
Fig. 14 – Wiring diagram MIL C-5015
F
E
D
CONTACT FUNCTION
A 1-NA
B 1-NC
C 1-C
D 2-NA
E 2-NC
F 2-C
G Ground
Once the crimping and assembly activities of the free connector
are finished, make sure that all the parts are tight. Screw the bay-
onet and tighten it to assure the instrument degree of protection
7.6
GROUNDING CONNECTIONS
The instrument is supplied with two grounding connections, one
external and one internal. The connections are suitable for a
earthing wires of 4 mm 2 section (fig. 2).
8

INSTRUMENT PLUMBING

8.1
Weatherproof pressure switches (Model MW)
The plumbing, aimed as a guarantee against possible tampering
of the calibration and electrical connections, can be carried out us-
ing a flexible steel wire (c) inserted into the holes in the screw (a)
and the bracket (e) provided for this purpose (see Fig. 4).
8.2
Flameproof pressure switches (Model MA)
Plumbing is not necessary as the cover is blocked with a headless
screw and the instrument does not have to be opened when in-
stalled (see Fig. 5).
9
SAFETY INTEGRITY LEVEL (SIL) INSTALLATION
REQUIREMENTS
The pressure switch has been evaluated as Type A safety related
hardware. It has an hardware fault tolerance of 0 if it is used in one
out one configuration (1oo1). The installation has to be designed
to allow a proof test to detect dangerous undetected fault using, as
example, the following procedure:
- Take appropriate action to avoid a false trip
- Force the switch to reach a define max or min threshold value
and verify that output goes into the safe state.
- Force the switch to reach a define normal threshold value and
verify that output goes into the normal state.
- Repeat the check two times evaluating average set point
value and repeatability,
- Restore the loop to full operation
- Restore normal operation
The installation requirements, the useful life and the failure of the
switch is discussed in the Failure Modes,Effects and Diagnostic
Analysis Report.
NI-221WE
Rev. 5 12/16
5- Ferrule
6- Insulator for pin contacts
7- Pin contacts
8- Shell
G
A
B
C
Micro 1: Normaly open
Micro 1: Normaly closed
Micro 1: Common
Micro 2: Normaly open
Micro 2: Normaly closed
Micro 2: Common
Internal grounding connection
5 of 9