background image

INSTALLATION & OPERATING DATA

Conditions or Restrictions for use in SIL Applications

The sections of this Installation and Operating Data Manual shall be strictly complied
with to ensure validity of the failure data and systematic safety integrity. The following
additional restrictions and conditions apply when the unit is used in SIL applications:

1.  The host controller must monitor the TX6373 Toxic Gas Sensor/Transmitter output

at an appropriate frequency for the application (safety time) and initiate a safe
action  (eg.  process  shutdown,  evacuation,  etc)  or  be  repaired  within  the  MTTR
assumed  in  the  PFD  calculations  shown  in  Table  2  in  Section  11.3  above,  if  an
out-of-range (low) output signal is indicated.

2.  If the MTTR or the proof test interval (T

1

) is different from those assumed in this

document, then the PFD

AVG

 should be re-calculated and the SIL capability

re-verified accordingly (refer to the Safety Manual in Section 11.5 below.

3.  The display is for indication only and is not part of the safety function.

4.  The environmental limits are restricted to:

·

 

+20 to +40

°

C

·

 

relative humidity <90%.

5.  IEC 61508-2, 7.4.4.3.1c limits use to SIL 1 in high or continuous mode of operation

when used in a non-redundant configuration.

6.  The  unit  must  be  calibrated  at  commissioning  and  at  3  month  intervals  during

operation and the sensor head replaced as indicated by the calibration check.

Proof Testing

Periodic proof tests of the element safety function must be performed to identify
any dormant failures, particularly when used in 'low demand' safety functions - refer
to Section 9.2 of this manual, for the proof test procedure. (Note that calibration
alone does not operate the 4 to 20 mA signal). Faults identified by this test must be
repaired within the MTTR and the unit returned to full working order.

A suitable proof test interval (T

1

) should be used in order to achieve the required

average probability of failure on demand (PFD

AVG

). A nominal interval of 8,760 hrs

(1 year) and Mean Time to Repair (MTTR) of 24 hours has been used in the derivation
of PFD

AVG

 for illustration purposes. If different values are used, the PFD

AVG

 for a

non-redundant  arrangement  (ie.  where  the  safety  function  relies  on  a  single
element) can be re-calculated as follows:

PFD

AVG

   =  (

λ

DU

 +

λ

DD

) t

CE

Where t

CE

 (the channel equivalent down time) = (

λ

DU

 /

λ

D

) (T

1

/2 + MTTR) + (

λ

DD

 /

λ

D

) MTTR

For redundant arrangements refer to IEC 61508-6 for the equations.

11.4

24/25

11.5

11 FUNCTIONAL SAFETY

continued

Those responsible for specifying proof testing of safety functions should refer to IEC
61508-6:2010 clause B.3.2.5 for considerations of the effect of non-perfect proof tests.

ISSUE N 06/15

Содержание TX6373

Страница 1: ... CONTROLS AND INDICATORS 13 8 CALIBRATION 14 9 MAINTENANCE 17 10 APPROVALS AND CERTIFICATION 20 PETROCHEMICAL PROCESSING MINING TUNNELLING OFFSHORE PLATFORMS MANUFACTURING PROCESS PLANTS STORAGEAREAS WAREHOUSING WATER MANAGEMENT SEWAGE TREATMENT POWERGENERA TION GAS STORAGE DISTRIBUTION TELECOMMS TX6373 TOXIC GAS SENSOR TRANSMITTER 1 25 ISSUE N 06 15 11 FUNCTIONAL SAFETY 22 ...

Страница 2: ...signal for convenient replacement and servicing Calibration available for a wide range of toxic gases Convenient push button calibration of ZERO and SPAN Signal fix during calibration to prevent false alarms 4 wire systems only Output signal versions 4 to 20 mA 0 4 to 2 V 5 to 15 Hz Anti static polycarbonate ABS housing Intrinsically safe for use in Group I and Group II hazardous areas Optional fo...

Страница 3: ...Gas storage and distribution Telecommunications A choice of output signals for direct interfacing with most standard industrial monitoring systems 2 APPLICATION TRIP AMPLIFIER for use with analogue output sensors CONFIGURABLE SENSOR CONTROLLER for monitoring up to 8 analogue output sensors COMMANDER DISTRIBUTED I O SYSTEM for large scale general plant monitoring systems and the mining and tunnelli...

Страница 4: ...oles for M6 Socket Cap Head Fixing Screws External Earth Terminal 110 97 2000 standard 148 External Earth Terminal 2 Holes for M6 Socket Cap Head Fixing Screws 124 0 15 0 26 0 3 1 TX6373 Toxic Gas Sensor Transmitter 3 2 TX6373 84 Toxic Gas Sensor Transmitter with Remote Gas Sensing Module METHANE CATALYTIC COMBUSTION ELECTROCHEMICAL SENSING LINEARITY DRIFT REPEATABILITY RESPONSE OPERATING ORDER Ca...

Страница 5: ...PLICATIONS 24 V dc Output 0 4 to 2 V dc Min Load 10 k ohms Supply 6 5 to 16 5 V dc Max Current 10 mA Output 5 to 15 Hz Max Load Opto isolated 2 mA max Supply 6 5 to 16 5 V dc Max Current 20 mA Output 4 to 20 mA Max Load 875 ohms 24 V dc Supply 6 5 to 30 V dc Max Current 24 mA Output 4 to 20 mA Max Load 875 ohms 24 V dc Supply 6 5 to 30 V dc Nominal Current 24 mA Refer to Section 6 Output 4 to 20 m...

Страница 6: ...e the correct safety barriers fitted 5 INSTALLATION A 20 mA 4 2 V 0 4 Hz 15 Hz 5 12 V dc 24 V dc GROUP I GROUP II GENERAL PURPOSE 5 1 Conformity Check TX6373 01 TOXIC GAS SENSOR TRANSMITTER GROUP I TX6373 02 TOXIC GAS SENSOR TRANSMITTER GROUP II TX6373 03 TOXIC GAS SENSOR TRANSMITTER GENERAL PURPOSE TX6373 84 01 TOXIC GAS SENSOR TRANSMITTER GROUP I with Remote Gas Sensing Module TX6373 84 02 TOXIC...

Страница 7: ...d to occur This way the earliest possible warning of a gas release can be given to initiate shutdown functions alarm functions or safe evacuation of the premises 5 3 System Integrity If a gas monitoring system should fail for any reason it is important that the system is capable of immediately alerting operational staff to this fact The sensor will indicate a system failure or mechanical defect an...

Страница 8: ...enches machine rooms etc Normal air movements in and around such gas concentrations will have the inevitable effect of producing zones of highly toxic mixtures This knowledge of the characteristics of the gas assists when positioning the gas sensor The behaviour of the gas accumulation will also be affected by the velocity and location of the gas release and by ambient air movement caused by venti...

Страница 9: ...ic gases can be affected by other interfering gases which may displace the subject gas being monitored Steam laden atmospheres and condensation can also reduce the sensitivity 5 10 Flammable Be aware that some toxic gases are also flammable at high percentage concentrations 5 11 Biased Sensors Some gas sensors must be continuously powered to maintain the calibration If the gas head is removed from...

Страница 10: ...so at some point influenced by the length of the cable and the resistance of the cable cores the current flowing in the 0 V conductor will impose an unacceptable voltage error onto the signal This effect can be reduced on long distance connections by increasing the size of the cable cores or even better running a separate 0 V conductor to power the sensor enabling operating distances up to 5000 me...

Страница 11: ... Supply TX6373 Monitoring Device A pull up resistor may be required at the monitoring device 6 4 Using Gas Sensors in Hazardous Areas 6 4 1 GROUP I HAZARDOUS AREAS MINING TX6373 01 TOXIC GAS SENSOR TRANSMITTER All options of the TX6373 01 sensor 0 4 to 2 V 4 to 20 mA and 5 to 15 Hz are certified Intrinsically Safe for use in Group I hazardous areas Mining when used with approved equipment eg TX913...

Страница 12: ... zener safety barriers NB IS EARTH MUST BE LESS THAN 10 OHMS LOOP RESISTANCE Max Cable Length 1 km using 1 5 mm2 cable conductors If you require any help with the use and connection of hazardous area equipment please contact the Trolex Technical Department Signal Safety Barrier MTL787S 1 2 3 4 5 6 7 8 1 2 4 3 MTL 787S V V Signal HAZARDOUS SAFE TX6373 02 Group II sensor connections using isolation ...

Страница 13: ...rotection Classification Dust and waterproof to IP66 Housing Material Brass or Stainless steel Maximum Cable Length Extendible up to 250 m using 1 5 mm2 cable conductors DISCONNECTING THE REMOTE GAS SENSING MODULE The connecting cable between the remote gas sensing module and the Transmitter is normally supplied connected at both ends The cable can be disconnected via a plug and socket connector i...

Страница 14: ...ture of the gas sensing module 8 2 Enter Calibrate Mode Press BOTH pushbuttons on the gas sensing module for about 5 seconds Then release The indicator will be RED denoting that the module is now setup ready for When the Gas Sensing Module is setup into the CALIBRATE MODE it will instruct the transmitted output signal of the sensor to be FIXED at a value of 0 00 This will prevent the possibility o...

Страница 15: ...3 times Release and the indicator will briefly show RED to denote ZERO setup The Gas Sensing Module will commence auto zero Once the auto zero has completed the indicator will briefly show amber to indicate trim mode has been entered G G R G TRIM MODE Trim mode allows the output from the GSM to be adjusted to give an accurate zero level During this mode the CALIBRATE ZERO button decreases the outp...

Страница 16: ...conds until the indicator is flashing YELLOW 3 times SPAN CALIBRATION will not occur if an insufficient concentration of span gas is present SCROLL the display value UP DOWN until it concurs with the value of gas concentration marked on the test gas canister 50 seconds after SCROLLING has ceased the gas sensing module will automatically return to the NORMAL measuring mode TEST GAS Y Y R G R Keep t...

Страница 17: ...ut the proof test 9 3 Gas Sensing Modules The gas sensing modules should be changed at regular intervals to ensure accuracy of response Electrochemical cells contain an electrolyte that is gradually consumed during use The average life is about two years influenced mostly by duty cycle ambient temperatures and humidity The shifting response of the cell should be checked at regular intervals The mo...

Страница 18: ...bush take care not to damage the internal filter and unscrew the gas inlet bush Remove the filter from the gas inlet bush Clean or replace the filter as necessary Fit a new or cleaned filter to the gas inlet bush Using a spanner remove the sensor retaining nut from the remote housing Remove the gas sensing module from the remote housing Fit a new gas sensing module to the remote housing refit the ...

Страница 19: ...Maintenance and Calibration Log ORDER REF TX6373 DATE SUPPLIED SERIAL No USER GAS TYPE LOCATION 9 MAINTENANCE continued DATE SCHEDULED FAILURE RE CALIBRATE CHANGE GAS RETURN TO COMMENTS SENSING MANUFACTURER MODULE 19 25 ISSUE N 06 15 ...

Страница 20: ... to the above certificate to ensure that the termination and cable parameters are fully complied with and are compatible with the application Copies of certificates are available from Trolex ATEX Directive 94 9 EC Australia New Zealand ANZEx TX6373 series Toxic Gas Sensor Transmitter Ex Certificate Number ANZEx 12 3016X Ex Certification Code Ex ia I Ta 20 C to 60 C Ex ia IIC T4 Ta 20 C to 60 C Spe...

Страница 21: ... 20 C Ta 60 C Specific Conditions of Use Under certain extreme circumstances the polycarbonate window may store an ignition capable level of electrostatic charge Therefore when it is used for applications that specifically require group II category 1 equipment the TX6373 shall not be installed in a location where the external conditions are conductive to the build up of electrostatic charge Additi...

Страница 22: ...pe of the TX6373 Toxic Gas Sensor Transmitter and will rely on personnel who are competent in the functional safety aspects of the various lifecycle activities mentioned above SIL Suitability The versions and configurations of the TX6373 Toxic Gas Sensor Transmitter identified in Table 1 in Section 11 3 below are suitable for use in gas detection safety functions that have a specified Safety Integ...

Страница 23: ...tion 4 of this manual 4 to 20 mA output Sensor types CO H2S SO2 H2 NH3 NO2 Cl2 NO O2 Element safety function Safety Manual 2 3 wire loop or 4 wire powered connection power supply and load as specification noting Group I certified equipment requirements To produce a 4 to 20 mA output that correlates with a specific toxic gas concentration range See Section 11 of this manual Table 1 Basic Element In...

Страница 24: ...guration 6 The unit must be calibrated at commissioning and at 3 month intervals during operation and the sensor head replaced as indicated by the calibration check Proof Testing Periodic proof tests of the element safety function must be performed to identify any dormant failures particularly when used in low demand safety functions refer to Section 9 2 of this manual for the proof test procedure...

Страница 25: ... OPERATING DATA 11 FUNCTIONAL SAFETY continued System Configuration Drawing The illustration below shows how the TX6373 is to be used with other system elements If a controller other than the TX9042 is used then the out of range fault indication signal from the TX6373 must be detected and acted upon to assert a system fault ISSUE N 06 15 ...

Отзывы: