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A B B ME A SUR EMENT & A N A LY TIC S | OPER ATING INSTRUC TION

AWT420

Universal 4-wire, dual-input transmitter

Measurement made easy

Introduction

The AWT420 is a universal 4-wire, dual-input 
transmitter suitable for the measurement and 
control of a wide range of parameters including  
pH, ORP, conductivity, turbidity/suspended  
solids and dissolved oxygen.

The AWT420 supports both traditional analog and 
advanced digital EZLink sensors. 

This Operating Instruction provides installation, 
operation and maintenance procedures for the 
AWT420 transmitter. For information on the 
sensors, including installation, commissioning, 
operation and maintenance procedures, refer to  
the specific sensor manual.

For more information

Further publications for the AWT420 transmitter  
are available for free download from: 

www.abb.com/measurement

 

or by scanning this code:

Links and reference numbers for the transmitter 

publications are also shown below:

Search for/click on:

AWT420 transmitter – Data Sheet

DS/AWT420-EN

AWT420 transmitter –  
Commissioning Instruction

CI/AWT420-EN

AWT420 transmitter –  
HART Communications Supplement

COM/AWT420/ 

HART-EN

AWT420 transmitter –  
HART FDS Communications Supplement

COM/AWT420/ 

HART/FDS-EN

AWT420 transmitter –  
PROFIBUS Communications Supplement

COM/AWT420/

PROFIBUS-EN

AWT420 transmitter –  
MODBUS Communications Supplement

COM/AWT420/

MODBUS-EN

AWT420 transmitter –  
Ethernet Communications Supplement

COM/AWT420/

ETHERNET-EN

AWT420  
Universal 4-wire,  
dual-input transmitter

Summary of Contents for AWT420

Page 1: ...procedures refer to the specific sensor manual For more information Further publications for the AWT420 transmitter are available for free download from www abb com measurement or by scanning this cod...

Page 2: ...s 15 2 electrode sensors 15 4 electrode sensors 15 Power supply connection 16 Fitting the EZLink modules 18 Connecting EZLink sensors 20 Long cables 20 6 Easy Setup 21 7 Calibration and sensor setup 2...

Page 3: ...atic calibration 65 In Process calibration pH 66 Sample collection 67 Sample complete 68 Temperature calibration 69 Turbidity Total Suspended Solids TSS 70 Turbidity TSS sensor verification 71 Prepari...

Page 4: ...rse acting control 105 Direct acting control 105 Dual acting control 106 Manual Reset proportional band offset 106 Output type 107 Analog output 107 Time proportioning output 107 Pulse frequency outpu...

Page 5: ...ury To ensure safe use when operating this equipment the following points must be observed Up to 240 V AC may be present Be sure to isolate the supply before removing the terminal cover Safety advice...

Page 6: ...n be hosed down if it has been installed to IP66 NEMA 4X standards i e cable glands are correctly fitted and all unused cable entry holes are blanked off see page 13 and page 12 Warm water and a mild...

Page 7: ...sensor interface board The process reading is displayed on the main page and can be displayed as a graph in the Chart View refer to page 29 for details of view options Diagnostic messages inform the...

Page 8: ...on providing easy access Avoid rooms containing corrosive gases or vapors for example chlorination equipment or chlorine gas cylinders Figure 2 Transmitter location Transmitter dimensions Dimensions i...

Page 9: ...n the left and right hand mounting brackets A into the recesses on the rear of the transmitter as shown and secure with the bracket securing screws Ensure the plastic washers remain in the positions f...

Page 10: ...he correct torque is critical to ensure proper compression of the panel seal and achieve the IP66 NEMA 4X hosedown rating 4 Holding assembly F together position bracket D into the left hand recess on...

Page 11: ...ate holes to suit vertical or horizontal pipe secure the clamp plate to the pipe mounting bracket B using two M6 x 8 mm hexagon head screws and spring lock washers C 3 Position the pipe mounting brack...

Page 12: ...Profibus and Ethernet communication wiring ONLY A special cable gland is supplied with the Ethernet communications option and should be used only for the Ethernet cable The use of cable glands cable...

Page 13: ...s module PCB slot Communication module connections refer to separate supplements HART COM AWT420 HART EN MODBUS COM AWT420 MODBUS EN PROFIBUS COM AWT420 PROFIBUS EN ETHERNET COM AWT420 ETHERNET EN AC...

Page 14: ...onductivity connections pH ORP pIon sensor module connections NOTICE ORP Redox and Antimony pH sensors do not feature temperature compensation therefore do not have temperature sensors or related wiri...

Page 15: ...ard sensors with diagnostic functions Sensor type RTD wiring SENSE 1 GUARD 2 REF 3 S GND 4 RTD 1 5 RTD 2 6 SHIELD 7 RTD 3 8 TBX5 2 lead Blue Yellow Black Green Red White Dark green AP2xx 2 lead Clear...

Page 16: ...ly 1 cable per cable gland Referring to Figure 11 page 17 1 Using a suitable screwdriver release door retaining screw A and open the transmitter door 2 Release terminal cover retaining screw B and rem...

Page 17: ...420 EN REV B 17 Figure 11 Connecting the transmitter AC mains power supply A D E F G H 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 GLASS GUARD REFERENCE SOLUTION EA R TH PT PT SCREEN PT 3 rd COMMUNICATIONS Sensor...

Page 18: ...onnector for sensor 1 passes through cable entry D b if two EZLink modules are used push fit sensor 1 module into location C and sensor 2 module into location E Note When fitting the cable assemblies...

Page 19: ...nnector body using the flats on the alignment washer see Figure 13 9 Screw back nut J onto connector body and tighten using a spanner Figure 14 Securing the EZLink connector cable assembly Referring t...

Page 20: ...nd push the connectors together 2 Turn nut C clockwise to secure the connectors together The transmitter detects the type of sensor connected automatically NOTICE When installing sensor extension cabl...

Page 21: ...vised changed at any time by selecting Enter Configuration from any Operator or View page menu followed by Advanced from the Access Level menu NOTICE If Easy Setup does not detect a key press within 5...

Page 22: ...meters may also include primary variable measurement units and measurement range The transmitter maintains a copy of these parameters as long as the sensor is connected Transmitter configuration param...

Page 23: ...og output the output s value is not held Sensor removal is classed as a failure by the diagnostic system and this overrides the existing analog output current 2 Connect the new sensor to the same EZLi...

Page 24: ...tputs during temporary sensor removal press the and select Manual Hold from the Operator page menu If a failure current has been configured for an analog output the output s value is not held Sensor r...

Page 25: ...items and decrease displayed values E Group key Toggles between Operator pages 1 to 5 when an Operator page is selected with the View key View screens Diagnostics View Signals View Alarms View and Out...

Page 26: ...g CAL shortcut D Press the key C below the CAL prompt Figure 19 Operator menus Operator menus comprise Operator Pages displays the Operator page for each available sensor Data Views displays enabled d...

Page 27: ...H and turbidity The highest priority diagnostic or alarm is displayed Other active diagnostic alarm states can be viewed on the Diagnostics View see page 22 Figure 20 Operator Page multiple sensors 4...

Page 28: ...fer to the sensor s Operating Instruction the bargraph flashes to indicate the value is outside the specified range When multiple sensors are fitted and Autoscroll is selected from the Operator Menu s...

Page 29: ...View 01 O2 O3 O4 CAL 04 09 2019 08 10 11 Diagnostics View PV Failure NV Error Cal Failed Cleaning NAMUR icon and message priority see page 83 Diagnostic message View icon No Message CAL 04 09 2019 08...

Page 30: ...shown in Table 3 The Diagnostics Log shows the history of diagnostic messages that have been displayed in the Diagnostic View see page Log entry Description Cal Failed Calibration procedure failed du...

Page 31: ...storing Do not expose to static electricity electrical noise or magnetic fields When handling an SD card take care not to touch any exposed metal contacts Back up critical data stored on removable med...

Page 32: ...imum permissible size a new file is created at 00 00 00 a m on the following day data is logged into the existing file continuously until the new file is created the daylight saving period starts or e...

Page 33: ...Access level screen Level Access Logout Displayed only after Calibrate or Advanced levels are accessed Logs the user out of the current level If passwords are set a password must be entered to access...

Page 34: ...larm hold and clean icons Alarm indicates a user defined alarm condition 20 character and flashes intermittently with an associated NAMUR diagnostic icon Hold indicates that alarms analog outputs are...

Page 35: ...brate Level indicates that the Calibration Level parameters are enabled for the current user Read Only Level indicates that the transmitter is in Read Only mode All parameters are locked and cannot be...

Page 36: ...of Data logging Load and save of configurations Refer to the relevant sensor manual for details of sensor setup menus Configuration of Process alarms Refer to the Calibration section page 55 for menu...

Page 37: ...Type User Defined Set the user defined buffer characteristic curve using the five point linearizer table pH against C N A Buffer 2 Set the type value of buffer solution 2 Supported buffer solutions fr...

Page 38: ...two 2 electrode conductivity sensors are fitted Access the Calculated Values specific setup pages refer to the Sensor setup section page Device Setup Used to access standard setup parameters Menu Comm...

Page 39: ...t be changed see page 27 View Log Enables Select to enable disable the following Views and Logs Diagnostics View See page 29 for examples of Operator pages in View mode Enable all Signals View Chart V...

Page 40: ...ng start hour in 1 hour increments 1 2 DS Start Occurrence Select the day within the month to start daylight saving For example to set daylight saving to start on the second Sunday of the selected mon...

Page 41: ...imum engineering range output values within the range of measurement permitted by the sensor selected as the source Enabled Failure Current Select to enable disable the output failure function When en...

Page 42: ...Type set to Continuous Clean on Time Recovery Time Clean Type set to Pulsed Clean on Time Clean Off Time x Number of Pulses Recovery Time N A Next Clean Set the date and time of the next scheduled cl...

Page 43: ...ee Process alarm examples Figure 32 and Figure 33 below Time Hysteresis Set a time hysteresis trip value between 0 0000 and 9999 0 seconds If the alarm trip value is exceeded the alarm is not activate...

Page 44: ...parameters to external media Up to 8 files can be created If a file exists in a position it is displayed as Config1 Overwrite Either overwrite the existing file or select a new position in which to sa...

Page 45: ...lue limited to PV Range PV range low Control Type P P I P I D P D P Proportional Band Numeric value 0 1 to 999 9 100 Integral Action Time If Control Type P I or P I D Numeric value 1 to 7200 s 1 sec D...

Page 46: ...Time If Output Type Time Proportioning Numeric value 1 0 to 300 0 s 10 sec Pulse Frequency If Output Type Pulse Frequency Numeric value 1 to 120 pulses per minute 60 pulses min Power Recovery Recovery...

Page 47: ...Energy module This allows users wireless communication with the transmitter using the dedicated CWA mobile application The mobile application is available for both Android and iOS operating systems N...

Page 48: ...s is fixed by the manufacturer and cannot be changed Firmware Revision The revision number of the firmware within the Bluetooth module eLabel The regulatory approval information for the Bluetooth modu...

Page 49: ...possible causes Tx Maintenance The transmitter requires maintenance see Appendix A page 42 for possible causes Tx Function Check The transmitter requires checking see Appendix A page 42 for possible...

Page 50: ...A Range High View the span value used in Chart and Bargraph views N A Range Low View the zero value used in Chart and Bargraph views N A Filter Type Select the signal filtering type None Low Medium Hi...

Page 51: ...The temperature compensation characteristic TC Curve for signal A should be set to NaCl Note The temperature compensation characteristic TC Curve for signal B should be set to NH3 Difference Calculate...

Page 52: ...numeric string 6 characters maximum for the custom user defined concentration units N A Conc Curve Table Set the user defined concentration curve using the 6 point linearizer table concentration again...

Page 53: ...Manual Automatic Note If Temperature Sensor type Manual the temperature value is not displayed in the associated Operator page or Signals View N A Low Slope Limit A pH probe degrades over time As thi...

Page 54: ...6 to 1114 mbar 380 to 835 mm Hg If the barometric pressure is unknown leave at the default sea level value of 1013 mbar 760 mm Hg 1013 mbar Reset To Defaults Select to reset all Sensor Setup parameter...

Page 55: ...be configured as a Conductivity Resistivity or Concentration device the smart one point calibration routine automatically uses the same units as the measured process variable Note Access the calibrat...

Page 56: ...to select Conductivity Cal and press the The Conductivity Cal menu is displayed 4 Confirm the displayed reading is stable and the key 5 Press the key to enter a new value the transmitter takes severa...

Page 57: ...ductivity or concentration device the smart one point calibration routine automatically uses the same units as the measured process variable Note Access to the Calibrate menu is via Calibrate and Adva...

Page 58: ...s the key The Conductivity Cal menu is displayed 4 Confirm the displayed reading is stable and the key 5 Press the key to enter a new value the transmitter takes several seconds to validate the calibr...

Page 59: ...on adjusts the check and slope values Note Automatic calibrations are not available for Redox ORP measurements Temperature Cal See Temperature calibration procedure page 69 Edit Cal pH Slope Note pH s...

Page 60: ...The calibration type is displayed 4 Use the key to edit the calibration type Use the keys to select the required calibration type and press the key to confirm selection Press the key to proceed to the...

Page 61: ...ess the key to perform the calibration The calibration process screen is displayed On completion the result screen is displayed If the calibration passes the slope and offset values are displayed If t...

Page 62: ...the keys to select the required calibration type and press the key to confirm selection Press the key to proceed to the next step The buffer temperature is displayed 5 Use the key to edit the buffer t...

Page 63: ...is displayed with the reason for failure If the calibration passes the procedure moves automatically to the high buffer calibration 9 Place the sensor into buffer 2 and press the key to perform the hi...

Page 64: ...libration type and press the key to confirm selection Press the key to proceed to the next step 5 Place the sensor into buffer 1 and press the key to perform the calibration The calibration process sc...

Page 65: ...and press the key to confirm selection Press the key to proceed to the next step 5 Place the sensor into buffer 1 and press the key to perform the low buffer calibration The calibration process screen...

Page 66: ...the sensor from the process to perform the calibration In this calibration mode the actual sample is used to calibrate the sensor In Process calibration is performed in two steps 1 Sample collection...

Page 67: ...data collection The Collect Sample progress screen is displayed When the procedure is complete a confirmation screen is displayed The value of the acquisition is now stored 5 Press the key to return...

Page 68: ...nter the value of the pH sample from the lab 6 Press the key twice 7 The Collect Sample screen is displayed with a prompt to enter a temperature value 8 Press the key and enter the value of the pH sam...

Page 69: ...ayed 5 Use the and keys to set the temperature and press the key to confirm changes The temperature calibration process screen is displayed On completion the result screen is displayed If the calibrat...

Page 70: ...idity TSS Sensor Verification page 71 Turbidity Cal See Turbidity calibration page 72 There are two possible calibration modes 1 point 2 point TSS Cal See TSS calibration page 76 There are two possibl...

Page 71: ...ys to set the value and press the key to confirm changes Press the and key to proceed to the next step 5 Ensure the sensor is inserted in the verification tool and press the key to start the verificat...

Page 72: ...er in situations where an offset was previously determined during a 2 point calibration it is possible to retain the previously measured offset during the 1 point calibration Use the key to edit the O...

Page 73: ...tine The calibration process screen is displayed On completion the result screen is displayed If the calibration passes the new settings are displayed If the calibration fails the reason for failure i...

Page 74: ...ey to proceed to the next step The Low Solution Value is displayed 5 Use the key to edit the solution value Use the keys to set the value and press the key to confirm changes Press the and key to proc...

Page 75: ...on 8 Ensure the sensor is inserted in the solution and press the key to start the verification routine The calibration process screen is displayed On completion the result screen is displayed If the c...

Page 76: ...value and press the key to confirm changes Press the and key to proceed to the next step 6 Ensure the sensor is inserted in the solution and press the key to start the verification routine The calibra...

Page 77: ...the next step The Low Solution Value is displayed 5 Use the key to edit the solution value Use the keys to set the value and press the key to confirm changes Press the and key to proceed to the next...

Page 78: ...essing the Abort key TSS manual calibration 1 At the Calibrate level press the key The Calibrate menu is displayed 2 Use the keys to select the sensor to be calibrated and press the key to confirm sel...

Page 79: ...p performed Sample collection 1 At the Calibrate level press the key The Calibrate menu is displayed 2 Use the keys to select the sensor to be calibrated and press the key to confirm selection The Sam...

Page 80: ...n needs to be reset then select Yes To retain the details of the previous calibrations then select No adaptive calibration to fine tune the existing calibration 5 Press the key to proceed to the next...

Page 81: ...yed 4 Use the key to edit the Calibration Type Use the keys to select the required Calibration Type and press the key to confirm selection Press the and key to proceed to the next step 5 Ensure the se...

Page 82: ...f the calibration fails the result screen is displayed with the reason for failure If the calibration passes the procedure moves automatically to the high buffer calibration 6 Ensure the sensor is sub...

Page 83: ...e requirements and adjust if necessary Memory Write Error Transmitter configuration data is corrupt or the transmitter s non volatile memory is faulty The device setup may be affected and changes to c...

Page 84: ...persists ensure that the sensor and the transmitter are compatible by upgrading the software on both via the bootloader 5 Check the Sensor Setup and correct if necessary see page 38 6 If Sensor Write...

Page 85: ...has failed calibration coefficients have not been updated and the previous values continue to be applied Visually inspect sensor for signs of damage or dirt and clean if necessary Check that sensor i...

Page 86: ...is complete S n Cal Failed The most recent sensor calibration has failed calibration coefficients have not been updated and the previous values continue to be applied Visually inspect sensor for signs...

Page 87: ...ears intact power cycle the instrument and allow 5 minutes for the signal to settle If the Reference Failure persists then the sensor must be replaced contact local service organization S n PT Failure...

Page 88: ...iagnostic is activated indicating that the sensor is reaching the end of its serviceable life and soon requires replacement 1 Visually inspect sensor tip for signs of damage or dirt and clean if neces...

Page 89: ...lean and fully submerged in the solution Repeat calibration if Calibration Failed persists then consider replacing the sensor S n User Cal Expired Recalibration of the RDO sensor is required The senso...

Page 90: ...er to the transmitter If PV Failure persists contact local service organization S n Wiper Failed The wiper has failed to wipe Sensor becomes soiled Measurement quality is affected due to inadequate cl...

Page 91: ...easuring the amount of light scattered by the sample at 90 from the direction of illumination Excessive ambient light can interfere with this and result in inaccurate readings Shade the sensor or if p...

Page 92: ...it hubs or EZLink connectors Security Password protection Access to configuration levels is enabled only after the user has entered a password Calibrate level user assigned password Advanced level use...

Page 93: ...4 to 158 F Altitude 2000 m 6562 ft max above sea level Audit log and Alarm log data are stored in the same log file 2 electrode conductivity Conductivity input Measurement range and resolution Cell c...

Page 94: ...eference temperature 25 C 77 F Configured output range Sensor group Min span Max span A 100 S cm 2000 mS cm B 10 S cm 2000 S cm pH ORP Redox pH ORP Redox input Sensor types pH Glass Antimony Sb ORP Re...

Page 95: ...s of IEC61326 for an industrial environment Approvals certification and safety Safety approval cULus CE mark Covers EMC LV Directives including latest version IEC 61010 General safety IEC 61010 1 Poll...

Page 96: ...reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures Reorient or relocate the recei...

Page 97: ...ues mVindication mV value indicated on the transmitter and proportional to the current output value T temperature of the solution in C after applying the factory and process calibration values Example...

Page 98: ...ct is eliminated at conductivities approaching that of ultra pure water in order to ascertain whether a conductivity variation is due to a change in impurity level or in temperature For conductivity l...

Page 99: ...on using only a single platinum resistance thermometer and mathematically calculating the temperature compensation required to give the correct conductivity at the reference temperature Figure 34 Ultr...

Page 100: ...mp2 imp1 1 2 Where Gimp1 Gt1 Gupw1 Gimp2 Gt2 Gupw2 Relationship between conductivity and total dissolved solids TDS measurement The TDS factor i e the relationship between conductivity S cm 1 and TDS...

Page 101: ...vity inputs must be configured as S cm 1 to calculate inferred pH WARNING The calculation of inferred pH relies on the strict control of chemical conditions within the NH3 NH3 NaCl or NaOH dosed sampl...

Page 102: ...line Monitoring on AVT systems with impurities Differential conductivity can also give an indication of sample pH on AVT systems where there are low concentrations of ionic impurities present in addit...

Page 103: ...1 3AC F 1 Where BC the before column reading AC the after column reading F molar conductivity change for the alkaline agent 243 S cm 1 per mmol l for sodium hydroxide The maximum after cation conducti...

Page 104: ...igital outputs and pulse frequency control outputs can be assigned to any of the available relays or digital outputs Operator pages Reverse or direct acting control A Instrument tag B Sensor specific...

Page 105: ...f Control Mode Manual is selected see Figure 37 Figure 39 Direct acting control In Configuration CAL Use the keys to toggle select SPA or Output mode Output mode enabled only if Control Mode Manual is...

Page 106: ...int Figure 40 Dual acting control Manual Reset proportional band offset A Manual Reset value is available on Reverse or Direct acting controllers when the integral term is disabled i e Control Type is...

Page 107: ...gned to any of the available relays or digital outputs the control output 0 to 100 is scaled linearly between 0 seconds and the configured cycle time 1 0 to 300 0 s to generate an ON period the relay...

Page 108: ...grade spares kit Part number 3KXA877420L0011 EZLink module assemblies AWT420 EZLink PCB upgrade spares kit Part number 3KXA877420L0015 Communications module assemblies AWT420 HART PCB upgrade spares k...

Page 109: ...Ethernet qty 1 1 2 in NPT qty 4 M16 qty 2 Ethernet qty 1 Ethernet gland qty 1 M16 Ethernet M20 1 in EZLink connector assembly Part number 3KXA877420L0066 EZLink extension cable assembly Part number De...

Page 110: ...this document and in the subject matter and illustrations contained therein Any reproduction disclosure to third parties or utilization of its contents in whole or in parts is forbidden without prior...

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