SERIES 290 DENSITY TRANSMITTER USER MANUAL
Contents
1. 4 2 3 Power Supply The transmitter requires a nominal supply of 24V dc but will operate between 12V to 30 V dc The maximum permissible loop impedance for a given supply is derived from the following equation ly Volts 12 Load in ohms 0 02 4 2 4 Integral Indicator Optional The three terminals A B C are for connection of alid mounted 3 1 2 digit indicator which may be specified as an option Where fitted this will be pre wired no other connection may be made to these terminals N B This is a non IS approved item 4 3 Atmospheric Reference A further central PG9 gland is fitted to the RT168A and fitted with a sintered breather plug For the Series 290 Density transmitter this has no function and may be left as fitted 5 0 COMMISSIONING RECALIBRATION Each instrument is manufactured and calibrated in accordance with its intended application and should not need further setting up Should the need arise however the zero and range settings may be adjusted as follows NB As stated earlier the unit will have been calibrated at its normal operational temperature It is essential that any recalibration is also carried out at this temperature Failure to do so can introduce significant measurement errors Note that this process requires the application of pressure to the lower diaphragm The construction of a particular unit will determine the type of pressure adaptor required It must ensure an effective pressure tight seal but mu2. material suitable for continuous immersion in water and many oils and chemicals When handling take special care not to damage this outer sheathing Do not bend the cable to a radius less than 50mm For submersible sensors the cable should not be used as a means of lowering or withdrawing the unit Where the cable is to be brought through to the tank wall it is recommended that where possible this be done above the maximum fill line using a suitable compression fitting Available from PSM The overall cable screen must be terminated at the PG9 entry gland to preserve the RFI EMC standards of the unit The cable employed is a PSM standard approved cable also used on hydrostatic level transmitters For these it requires a vent tube to provide an atmospheric reference for the sensor For the 290 Series this vent tube is not required and may be cut back as convenient The sensor cable will have been supplied to suit the installation and since it forms part of a tuned circuit any excess should be coiled rather than cut back The following diagrams illustrate the termination arrangements and correct procedure for connecting the sensor cable Cable preparation Remove outer sheath trim outer INPUT CABLE ASSY _ screen to 20mm Cut vent tube back Cut and strip wires and no 20 23 inner screen as Fig 1 Sen vere gt Fit bootlace ferrules to black red green amp inner screen ends and Fig 2 AS ai crimp Fit cable gland l
3. Responding to applied pressure ie the output signal increases but unable to set 4mA output at zero using the zero potentiometer Disconnect the Black and Red sensor wires Can 4mA now be set If YES the sensor has a mechanical shift and will need replacing If NO a component failure in the amplifier module is indicated The amplifier should be replaced NB Since the thermal compensation for the sensor is calibrated into the Amplifier the advisability of doing this depends upon the service conditions Where there are no extremes of temperature involved it may be viable Refer to PSM who will determine this from the factory calibration records 2 Not responding to applied pressure Dissconnect the Red and Black sensor wires Is it now possible to set 4mA output on the zero pot If YES it indicates a sensor problem or no exitation voltage being supplied by the amplifier module To check the exitation voltage connect an AC voltmeter across the Ex Ex terminals Output should read 0 7V If an oscilloscope is available the frequency of the excitation voltage can also be verified as 1 3KHz If NO there is a problem with the amplifier module To check the supply rails the amplifier must be removed from its housing to gain access to the lower board Check that the voltage across Diode Z1 is 5 2V Z1 is located in the centre of the board and its unbanded end is OV Measure also from this OV to pin 13 of IC4 This should be 1 9V Any variation from
4. 37 24 IIB 0 39 1 11 72 IIC 1 04 2 96 192 TABLE 2 TERMINAL NUMBERS POWER SUPPLY SAFE AREA CONNECTIONS HAZARDOUS AREA REFERENCE NO CONNECTIONS 15 3 6 MTL2441B 15 1 MTL3041 4 MTL4041 CON2 CON2 PIN14 PIN13 MTL5041 CONS CONS CON4 CONI CONI PIN14 PIN13 PIN11 PIN2 PINI SINEAX B811 TYPE B811 13 OR 10 9 si 1 TYPE B811 14 11 7 0 GENERAL OPERATION MAINTENANCE Where correctly installed satisfactory continuous performance over a long period may be expected from the transmitter The unit has no specific maintenance requirement However the following periodic checks are recommended to good working order 1 ii iii The system components should be checked visually for good condition of the housings ensuring that doors and lids are kept firmly closed Check that weatherproof gasketsand seals are in good condition and secure Electrical cable runs between the system components should be inspected for condition and security and that cable glands are securely fastened If the sensor is to be used in an application where the accumulation of sludge may be formed around the diaphragm assemblies after a period of time cleaning may be necessary otherwise a slow response to level changes or an inaccurate reading may result The cleaning procedure is as follows a b d e Remove the transmitter from service Clean and dry the unit externally using clean water or suitable solvents
5. ATUS WHICH IS UNSPECIFIED EXCEPT THAT IT MUST NOT BE SUPPLIED FROM NOR CONTAIN IN NORMAL OR ABNORMAL CONDITIONS A SOURCE OF POTENTIAL WITH RESPECT TO EARTH IN EXCESS OF 250 VOLTS R M S OR 125 VOLTS DC NOTES THE ELECTRICAL CIRCUIT IN THE HAZARDOUS AREA MUST BE CAPABLE OF WITHSTANDING AN A C TEST VOLTAGE OF 500 VOLTS RMS TO EARTH OR FRAME FOR A PERIOD OF ONE MINUTE a 2 THE CAPACITANCE AND EITHER THE INDUCTANCE OR THE INDUCTANCE TO RESISTANCE L R RATIO OF THE HAZARDOUS AREA CABLE MUST NOT EXCEED THE VALUES GIVEN IN TABLE 1 3 THE INSTALLATION MUST COMPLY WITH THE INSATALLION REQUIREMENTS AS SPECIFIED IN BSEN 60079 14 1997 4 ANY ONE OF THE FOLLOWING POWER SUPPLIES MAY BE USED AN MTL2441B REPEATER POWER SUPPLY BASEEFA CERTIFICATE NO Ex92C2462 AN MTL3041 REPEATER POWER SUPPLY BASEEFA CERTIFICATE NO Ex86B2031 AN MTL4041 REPEATER POWER SUPPLY 4 20mA BASEEFA CERTIFICATE NO Ex92C2003 AN MTL5041 REPEATER POWER SUPPLY 4 20mA BASEEFA CERTIFICATE NO Ex95D2339 A CAMILLE BAUER AG SUPPLY UNIT SINEAX B811 TYPE B811 13 OR TYPE B811 14 CERTIFICATE NO PTB 97 ATEX 2083 N B THE CAMILLE BAUER AG SUPPLY UNIT SINEAX B811 TYPE B811 1 ALTHOUGH MEETING THE SEGREGATION REQUIREMENTS FOR UNSPECIFIED SAFE AREA APPARATUS OF 375V PEAK IS SUBJECT TO OPERATIONAL LIMITATIONS OF VOLTAGE FOR DETAILS SEE THE CERTIFICATE SEE TABLE 2 FOR CONNECTION DETAILS TABLE 1 GROUP CAPACITANCE uf INDUCTANCE mH OR L R RATIO MICROHENRIES OHM IIC 0 13 0
6. Psi PSM INSTRUMENTATION LTD SERIES 290 DENSITY TRANSMITTER USER MANUAL Issue B date 23 10 2001 Burrell Road Industrial Estate H aywards Heath West Sussex RH16 1TW UK Tel 44 0 1444 410040 Fax 44 0 1444 410121 Http www psm sensors co uk E mail sales psm sensors co uk Doc Ref Man 04 SECTION 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 10 0 11 0 CONTENTS TITLE Introduction Model Designation General Specifications Installation 4 1 Mechanical Installation 4 2 Electrical Installation Commissioning Recalibration Intrinsic Safety General Operation Maintainance Fault Finding Sensor A mplifier Module Replacement Warranty Conditions General Outline drawings PAGE o un A U WU W 1 0 INTRODUCTION PSM 290 Series transmitters are designed for monitoring the density of various liquids Whereas the measurement principle remains the same for all duties the specific construction will vary dependant upon the type of product being monitored For example in measurement of liquid foodstuffs a hygienic construction may be employed where the measurement elements are housed in flush mount crevice free fittings for mounting on the vessel wall Conversely for offshore use in drilling mud measurement the unit is normally of submersible construction and will incorporate a guard assembly for each of the measurement diaphragms The separation distance of the two pressure sensitive diaphragms may also var
7. Where fitted carefully unscrew by hand only the diaphragm housing end cover or flange plate from the front of the transducer If use of tools is required use extreme care DO NOT INSERT ANY TOOLS OR OBJECTS THROUGH THE SENSOR END CAP OR THE FRONT PROTECTION GUARD WHERE THEY MAY COME INTO CONTACT WITH THE DIAPHRAGM When unscrewed keep the assembly parallel and gently lift away from the body exposing the diaphragm Using suitable solvents or clean water only carefully clean the sludge deposits from the exposed diaphragm or pressure chamber depending upon model Great care must be taken not to damage distort or otherwise manipulate the diaphragm A soft brush may be employed to work the solvent into accumulated sludge if required On no account should high pressure cleaning devices be used Clean and inspect any gaskets or seals and ensure that the seating is thoroughly cleaned Replace seals if necessary When refitting the end cover or flange plate ensure that it is kept parallel and clear of the diaphragm It is also recommended that system calibration should be checked at least once a year following the procedure given under section 5 0 entitled Commissioning amp Recalibration 12 8 0 FAULT FINDING During manufacture each instrument is exercised and calibrated in accordance with the application requirements As such it is fully tested prior to shipment If however on installation or subsequently in service the syst
8. e cable to a remotely sited amplifier module This output signal is then processed by the amplifier to provide an industry standard 4 20mA signal The amplifier also incorporates range and zero adjustment facilities The product is designed and approved for use in hazardous 1 5 classified duties to EEx ia IIC T6 2 0 MODEL DESIGNATION Each transmitter amplifier module bears an identification plate which carries both the model code and a unique serial number The model code identifies the Nominal and set ranges and length of cable fitted The Model Code may also be suffixed by a V number This indicates a variation from standard product for example a special process connection for a particular duty Where a V code is found the accompanying order paperwork will identify it Note The sensor is also marked with the Serial Number and the units MUST be employed as a matched pair to preserve factory calibration 3 0 GENERAL SPECIFICATIONS 3 1 Sensor Construction Body assembly 316L stainless Steel Diaphragms Hastelloy C276 Mounting External flanged or threaded or internal submersed Calibrated Range Density span 0 5 to 3 00 with zero offset to suit Fluid fill Silicon or Mineral oil Operating temperature 10 to 120 Degrees Centigrade Temperature compensation As required by application 3 3 2 Sensor Cable Construction Depending on duty either 4 core with overall screen or 2 core and miniature coaxial with overall screen Outer shea
9. ely sensitive diaphragms Any mechanical damage to these will affect the performance and accuracy of the Instrument Care must also be taken to avoid stressing or chafing of the cable insulation 4 1 3 Electronic Transmitter The RT168A provides the excitation supply for the sensor and amplifies and conditions the return signal to provide a standard 4 20mA output The unit is housed in a weatherproof GRP enclosure suitable for wall mounting Fixing details are given at the rear of the manual In general this unit should be mounted away from extremes of temperature eg Not in direct sunlight vibration or where likely to be continuously sprayed with water in the last case an optional IP67 enclosure is available 4 2 ELECTRICAL INSTALLATION The unit should be wired in accordance with the following diagrams The sensor cable is terminated in the RT168A electronic transmitter following the wire colour code marked on the printed circuit card The sensor cable consists of Black conductor connect to EX Red conductor connect to EX Coaxial conductor green connect to OP Coaxial screen connect to OP SO O as e IAS Ear E 9 Test Points SIGNAL 3 m 4 to 20 mA A m 10 35 Volts DC Input Sensor Input cable PSM supply Cable 2 core screen Sintered Breather Customer supply Port 4 2 1 Sensor cable The cable is factory fitted to the transducer The outer sheathing is a special
10. em is believed to be providing an incorrect reading or no reading at all the checks should be undertaken Note that the sensor assembly is a fully welded construction and apart from removal of any diaphragm covers or protection no on site disassembly is possible 1 2 5 Check that the actual installation details are as the original manufacturing specification Is the system wired in accordance with the instructions given in the electrical installation section Is the power connected and working Is the correct 24 V dc signal present across the transmitter terminals Connect a voltmeter suitable for 24V DC across the units positive and negative terminals offering correct polarities Does the current output from the transmitter appear at the receiving instruments terminals Connect an ammeter suitable for 4 to 20mA in series in place of the loop indicator If possible confirm by independent means the actual SG of the liquid Be aware of any apparent errors introduced by stratification of fluids 6 7 8 its 10 Check that the liquid is fluid ie no solids or other blockages are impeding the diaphragms For externally mounted transmitters check that any isolating valves fitted are open Where a number of transmitters have been installed check that each sensor is installed on intended vessel and has the correct electronic transmitter connected Where the transmitter has an indicator connected check that this is not f
11. equivalent to the minimum SG to the lower diaphragm and adjust the zero potentiometer to give a 4 00mA output 5 2 Range adjustment Adjustment of the range setting is as described for zero having first applied a pressure equivalent to the maximum SG value 6 0 INTRINSIC SAFETY 290 Series transmitters are covered by intrinsically safe certification for use in hazardous areas Approval certification RT168A Amplifier Sensors BAS No Ex 86B2028 CODE EEx ia IIC T5 BAS No Ex 86B2029 CODE EEx ia IIC T6 The above approval codes are defined as follows Ex ia 5 Indicates the CENELEC standard Indicates that the equipment cannot cause ignition in normal operation or with any combination of up to two faults applied Refer to BS5501 Part 7 and EN50020 Indicates the group of gases vapours defined in BS5502 Part 1 and EN50019 Indicates the maximum surface temperature category as defined in BS4683 Part 1 The following is a reproduction of the schedule for certificate of assurance No EX86030 which covers installation criteria A full copy of the certificate ia available on request PRESSURE SENSOR SERIES 200 300 RT168 OR RT861 Ex 8682029 Ex 8682028 PRESSURE TRANSMITTER INPUT INPUT HAZARDOUS AREA 10 ISOLATED POWER SUPPLY SUPPLY SUPPLY SAFE AREA SAFE AREA APPARATUS APPAR
12. han that allowed for the unit will prove slow to react and lose sensitivity Where it is higher than allowed for temperature induced errors and over sensitivity will occur The arrangements for mounting the sensor to the tank should also be examined It is essential for correct operation that the unit is installed vertical such that it sees the correct hydrostatic pressure Ensure that the correct length of cable has been fitted to the sensor Note The cable is factory fitted to ensure a pressure tight seal on the submersible sensors NO ATTEMPT SHOULD BE MADE TO REMOVE THE CABLE GLAND Each transducer and transmitter are factory calibrated as a matched pair and for both carry the same serial number It should be ensured that these match 4 1 MECHANICAL INSTALLATION 4 1 1 Sensor fitting position As previously stated the sensor must be vertically mounted The actual position in the tank should be as far away from any agitators inlets outlets and heating devices as possible Where the product being measured in liable to stratification bear in mind when considering the sensors location that the output from the unit will represent an average of the Density above the lower diaphragm only The sensor should not be mounted where it will be subject to excessive or continuous vibration or risk of mechanical damage 4 1 2 Fitting the sensor During installation the sensor should be handled with care especially with regard to the extrem
13. itted with shipping stops or bridge Where there is more than one transmitter connected to a common power supply check that there is no cross channel interference or ground loop problems How this is actually done will depend on each particular application but in general each transmitter should be connected individually to the supply or a temporary supply to see if its output signal changes If the fault still exists after the foregoing have been checked the transmitter should be removed from service for further examination 13 With the instrument throroughly cleaned and on the bench the following checks may be made Disconnect the sensor from the amplifier module and measure the resistance on the sensor signal cable which should be Black to Red Approximately 56 ohms Green to Inner Approximately 2200 ohms Check that the following are all open circuit Black to Green Black to Outer Screen Black to Sensor Body Green to Outer Screen Green to Sensor Body If any of the above tests fail the sensor is faulty and will require factory repair or replacement Assuming the above to be OK reconnect the sensor and the amplifier and connect a suitable 24V DC supply to the transmitter Connect an ammeter across the test pins on the amplifier to monitor the 4 20mA loop A suitable pressure source will also be required Refer to section 5 0 for details of applying pressure to the unit Check for the following conditions 1
14. l to give an output signal of 18 4 18 5mA 6 Reduce the pressure to the minimum SG level and recheck zero output re adjusting RV2 if necessary to give 4 00mA 7 Re apply the full nominal pressure and check output signal adjusting to 18 4 18 5mA using RV3 as necessary 8 Now apply a pressure equivalent to the maximum SG for full scale and adjust RV4 to give 20 00mA output 9 Release the pressure and recheck zero output If it requires correction repeat step 8 afterwards Repeat this process until a 4 20mA output is achieved 10 0 WARRANTY CONDITIONS PSM products are covered for 12 months from the date of despatch against arising from faulty manufacture Warranty terms are return to base Shipping costs are to the account of the user Should it prove necessary to return any equipment PSM must first be contacted to obtain a goods return authorisation number In accordance with UK Health and Safety policy PSM can refuse unauthorised returns An explanation of the apparent fault together with details of the service conditions are also requested The Health amp Safety requirements mean that we must be fully aware of any potential hazards prior to working on returns 11 0 GENERAL OUTLINE DRAWINGS Outline drawings for all models covered by this manual are available from PSM Due to the variety of configuration possibilities details of the specific model supplied against a particular contract are included as part of the contract docume
15. ntation 15 193 7 5 178 7 0 gt SENSOR CABLE TI agag mance O i EX OF 23 S epee re fam gi EN R Indicafor rear sa O EE a ta RT168A_4 20mA PE ZERO Je TWO WIRE TRANSMITTER O Sensor input PG9 cable Fal gland 1 dia 316 welded tube hygienic welding 1 malepart and seal All Welded Construction Diaphragm Protection Cage Diaphragm Seperation 12 Location Boss Customer Supply 16 2222222222222222 5 amp PG9 cable gland i with sintered Sn 50mm HYGIENIC FITTING breather distance h S Sensor cable Di ienic A dl nut ua Heavy Duty TPE Cable Pole Adapter Welded Equal Tee 1 Dia 316 Welded Tube 76 3 0 Tank Base Output signal cable gland PG9 PG11 PG13 5 or PG 16 As required Diaphragm Protection Cage
16. ocknut and rub ber sleeve as Fig 2 m bootlace 3 gt ferrules Fit cable gland inner sleeve and rigs gt fold outer screen wires back over sleeve as Fig 3 Fit cable gland body over wires as Fig 4 O ring to outside Tighten cable gland in position as Fig 5 Fig 5 4 2 2 Output loop As sensor cable omitting inner screen and vent tube The signal output cable screen must be earthed at supply end to preserve the Instruments RFI EMC screening The signal power loop should be connected as shown in the following diagram Two core screened cable should be used with a minimum conductor size of 0 5mm A larger conductor size may be employed to reduce loop impedance All connection should be made in series as illustrated The screen of the signal cable should be connected to the cable gland as described for the sensor cable TRANSDUCER nea 55525 INDICATOR Test Points OUTPUT SIGNAL 4 to 20 mA 10 35 Volts DC Input Sensor Input cable Cable 2 core screen PSM supply Sintered Breather Customer supply Port screen to be terminated to cable gland 24V de Supply NOTE PG9 cable gland is fitted as stan dard for the output signal cable However if specified a larger gland may be fitted during manufacture Following wiring the lid must always be refitted and tightly sealed Connect cable screen at supply end only Auxiliary equipment
17. st not connect with the diaphragm in any way Consult PSM for assistance in this respect A pressure source and Ammeter are also required these should be of certified and traceable calibration Finally the unit must be powered as described in section 4 2 2 Note It is common for a unit to be calibrated with an elevated zero representing the minimum SG In such cases this pressure must be applied to the lower diaphragm before the signal rises above 4 00mA When the entire assembly is in free air the output from the amplifier will be at quiescent of around 3 2mA The zero adjustment is 10 and range provides a 3 1 turndown both of the nominal range Taking as an example the common application of Drilling Mud density measurement in the offshore sector and a typical span of 8 to 20 Ibs U S Gallon and assuming a diaphragm separation if 12 inches 304 8mm the actual differential pressure range is calculated as 8lbs USG Density is 0 95872 12 x 0 958720 11 505 292 2mm WG 20lbs USG Density is 2 3968 12 x 2 3968 28 762 730 54mm WG The sensor must be mounted vertically throughout the calibration process Test pins marked amp are provided on the RT168A terminal board to allow monitoring of the 4 20mA loop without disconnecting the signal lines 5 1 Zero adjustment Zero adjustment is by means of a potentiometer which can be found in the bottom right hand corner of the RT168 transmitter Apply a pressure
18. these two values indicates a problem with the amplifier module 14 Where the foregoing do not clearly indicate the faulty element careful visual inspection of the sensor body diaphragms should be made for signs of damage corrosion the sensor cable for signs of damage to the outer sheathing and the circuit board for component failure or breakage may indicate where the problem lies If the faulty area can be identified and a spare sensor or amplifier module is available the following matching procedure should be undertaken NB As stated earlier please initially refer to PSM before undertaking the following procedure 9 0 SENSOR AMPLIFIER MODULE REPLACEMENT 1 To access the potentiometers on the lower PCB of the amplifier module it is necessary to remove the assembly from its enclosure Take care not to damage the boards or interconnecting ribbon cable 2 Connect sensor to transmitter and apply power as previously described 3 Set the potentiometer controls as follows RV1 Phase control fully anti clockwise Lower PCB RV2 Zero control mid position Upper PCB RV3 Gain control fully anti clockwise Lower PCB RV4 Range control fully anti clockwise Upper PCB 4 With a pressure equivalent to the minimum SG applied adjust the zero control RV2 to give an output signal of 4 00MA 5 Apply a pressure equal to the full nominal range of the instrument refer to the model coding label and adjust RV3 gain contro
19. thing either in XLPE or Hytrel Teflon Maximum length 100m 200m to special order 3 3 Electronics Module Housing GRP surface mounting to IP65 optionally IP67 Equivalent to NEMA 4X Connection 1 x PG9 gland for sensor cable 1 x PG9 gland for atmospheric reference not required 1 x PG9 gland for 4 20mA output optionally PG11 PG13 5 or PG16 Power requirement 12 30 V dc Signal output 2 wire 4 to 20mA dc Maximum load Dependent on supply 1000 ohms at 30V DC Range adjustment 3 to 1 electronic turndown of sensor nominal range Zero adjustment 10 of set span 3 4 Performance Maximum Error 0 25 of full range output Optional 0 1 some variants Temp Coefficient Less than 0 05 deg c range amp zero Optional 0 02 3 5 Options Intrinsically safe unit available to EEx ia IIC T6 4 0 INSTALLATION Pre installation checks Prior to installation it is recommended that the following checks are made Ensure that the factory calibration is in accordance with the actual process parameters Of particular importance is the operating temperature range Units will have been compensated for a particular range and operating outside this will result in errors of measurement due to the thermal expansion coefficient of the hydraulic filling fluid employed to link the two diaphragms The actual volume of the fill fluid used during manufacture is a function of the in service temperature If the actual temperature is lower t
20. y dependant upon the Density range and depth of measured liquid Each unit will have been despatched with a specific General Arrangement drawing This must be referred to for detailed information regarding construction The basic measurement principle is Differential Pressure Two pressure sensitive diaphragms are mounted vertically in the liquid at a known separation distance Provided both diaphragms remain covered a differential pressure will exist between them which is a function of the separation distance and the Density of the liquid Since the separation distance is fixed any variation in differential pressure 15 attributable only to Density change The diaphragms deflect progressively according to the applied pressure and are linked internally by an oil filled sealed capillary tube Thus the deflection of the upper diaphragm opposes that of the lower but since it is presented with a higher pressure its displacement is still positive This lower diaphragm is rated to give a known displacement for a known applied pressure Attached to the inside of this diaphragm and not exposed to the process is a ferro magnetic core This core is positioned centrally within a high resolution Linear Variable Differential Transformer The LVDT has a central primary and a secondary coil at each end Movement of the diaphragm results in a change in magnetic flux and hence output voltage from the secondaries The sensor output voltage is carried via a 4 cor
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