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Hawker P7/I.S. Скачать руководство пользователя страница 16

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maintained between the terminals if using multiholders to prevent them from touching one
another. The collar is placed over the electrode and fixed using the Allen key provided; the
terminating cable is then attached, or a screw is used for direct connection.

7.

CABLE SELECTION

6.0

CABLE PROPERTIES

All cables have an inherent capacitance and inductance, these values must be limited to
allow  only  small  energy  levels  going  into  the  hazardous  area.    The  total  allowable
capacitance  and  inductance  should  be  strictly  adhered  to  so  as  not  to  infringe  the
certification, this is shown on drawing 2920, see also section on “system”.
The capacitance and inductance values stated are for the total amount of cable of all the
systems  in  any  one  sump,  tank  or  vessel.    The  capacitance  being  that  of  P1  and  P2
conductors measured to the cable screen or armouring.  The inductance is the sum of all
conductors  used  for  P1,  P2  and  G  connections.    Examples  of  calculating  cable
capacitance and inductance follow.

6.1

Cable inductance

Example of calculating cable inductance

Method A.

As the L/R Ratio remains constant regardless of cable length, this is the

easiest method. For example, it will be seen referring to Table 1 that for 1.5mm

2

steel wire

armoured cable the L/R ratio is 28

µ

H/

Ω

and looking at drawing 2920

tables this meets the

requirements for all gas groups for up to 6 systems and groups 11A and 11B for up to 10
systems .

Method B.

Assuming two controllers are being used for pump control using both P1 and

P2, and two controllers for High and Low level alarms using the P1 connections and one
earth electrode (G), thus 7 cables in all.
The maximum inductance permitted from drawing 2920 table for Group 11C for 6 systems
is 0.78mH. Reference Table 1, a 2.5mm

2

steel wire armoured cable having an inductance

of 0.32mH per 1000m so –
The total cable length permitted is (0.78 / 0.32) x 1000 = 2437m, or
2437 / 7 = 348m per electrode circuit.

terminal

solder/crimp

lock washer

plain washer

nut

Allen key
fixing

electrode

terminal

solder/crimp

lock washer

plain washer

screw

electrode

Screw arrangement

Collar
arrangement

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Содержание P7/I.S.

Страница 1: ...troller type P7 I S Certificate No SIRA03ATEX2160X Electrode Holders Certificate No SIRA03ATEX2159X Conductivity Operated Level Control System Certificate No Ex03E2161 Hawker Electronics Limited O M 7...

Страница 2: ...4 2 3 Basic controller testing 10 4 3 Technical specification 12 5 0 Electrode Holders 13 5 1 Cat 1 Electrode holders 13 5 1 1 Type identification 13 5 1 2 Certification markings 14 5 1 3 Conditions o...

Страница 3: ...ected the unit either de energises or energises its internal relay dependent on the fail safe setting providing the user with a set of volt free S P C O contacts The unit may be used for High or Low a...

Страница 4: ...acing ventilation or cooling should be provided Ambient operating temperature ranges other than 20 C to 40 C will be indicated on the product label The equipment is intended to be used only in dry cle...

Страница 5: ...se to a spread of additional risks in the event of a power failure it must be possible to maintain them in a safe state of operation independently of the rest of the installation this is the responsib...

Страница 6: ...uipment shall only be carried out by the manufacturer or in accordance with the applicable code of practice 6 The certification of this equipment relies on the following materials used in its construc...

Страница 7: ...rnal relay contacts These relay contacts must not switch more than 5A r m s or 250V r m s or 100 VA 4 1 4 Electrical connection and housing The electrical connections are made to the terminal blocks s...

Страница 8: ...IS technical specifications for ordering information Always check to ensure the controller specifications are suited to the supply and its application before installing The input supply fail safe set...

Страница 9: ...ded that this manual be used for optimum performance No attempt should be made to remove this trim Precautions before testing Before disconnecting any mains leads or control wiring at the controller o...

Страница 10: ...erating cycle to ensure correct operation 4 2 3 Basic controller testing If necessary the controller can be tested without connecting to the electrode holders so its correct basic function and the use...

Страница 11: ...e supply to the volt free contacts has been switched OFF and remove the wires from the terminal block Use an approved ohmmeter to measure the contact resistance Check with the Relay de energised Led O...

Страница 12: ...cial low range to approx 7K Ohm Switching response 1s Operating Temp 20 C to 40 C Cable Typically 70m See drawing 2920 for maximum permitted Levels for intrinsic safety Capacitance max before sensitiv...

Страница 13: ...gases that may attack metals or solvents that may affect polymeric materials Suitable precautions e g regular checks as part of routine inspections or establishing from the material s data sheet that...

Страница 14: ...Sira 03ATEX2159X may be used in zones 0 1 and 2 with flammable gases and vapours with apparatus groups IIA IIB IIC and with temperature classes T1 T2 T3 T4 T5 and T6 The ambient temperature operating...

Страница 15: ...recommended distance is 23cm Using plastic coated electrodes which are available from stock can eliminate bridging always bare at least 50mm of the coating and have the reference G electrode central...

Страница 16: ...alculating cable capacitance and inductance follow 6 1 Cable inductance Example of calculating cable inductance Method A As the L R Ratio remains constant regardless of cable length this is the easies...

Страница 17: ...ch as the HPE8 when mounted 230mm apart may be up to 18m in length before this figure is exceeded Light duty electrodes such as the HPE7 mounted 75mm apart may be up to 15m in length which is far beyo...

Страница 18: ...ed except that it must not be supplied from nor contain under normal or abnormal conditions a source of potential with respect to earth ground in excess of 250V a c r m s or 250V d c and ii Controller...

Страница 19: ...roller G terminals Where a multiple controller system uses a Holder Type 1G 0 HPE5 IS as a common G holder the maximum number of P1 P2 holders that may be fitted is five 7 4 Permissible interconnectin...

Страница 20: ...Page 20 of 22...

Страница 21: ...K Notified Body Sira Certification Service 0518 Rake Lane Eccleston Chester CH4 9JN Conformity has been demonstrated with reference to the following documentation EC type examination certificate Sira...

Страница 22: ...Page 22 of 22...

Страница 23: ...l 41 41 541 5877 Fax 41 41 541 5878 Email General Information Sales info kesn ch Accounts Department accounts kesn ch USA O ce 233 Rogue River Highway 425 Grants Pass Oregon 97527 5429 USA Tel 1 503 2...

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