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Teledyne Analytical Instruments

 

 

OPERATING INSTRUCTIONS FOR 

LXT-280 

Dissolved Oxygen 

Transmitter 

 

 

 

 

 

 

 

 

 

DANGER 

 

Toxic gases and or flammable liquids may be present in this monitoring system. 

Personal protective equipment may be required when servicing this instrument. 

Hazardous voltages exist on certain components internally which may persist 
for a time even after the power is turned off and disconnected. 

Only authorized personnel should conduct maintenance and/or servicing. 
Before conducting any maintenance or servicing, consult with authorized 
supervisor/manager. 

P/N M 

 

ECO:  

 

 

 

 

 

Summary of Contents for LXT-280

Page 1: ...rsonal protective equipment may be required when servicing this instrument Hazardous voltages exist on certain components internally which may persist for a time even after the power is turned off and...

Page 2: ...eight of any parts in so far as such alterations do not adversely affect our warranty Important Notice This instrument provides measurement readings to its user and serves as a tool by which valuable...

Page 3: ...ssolved Oxygen Transmitter Teledyne Analytical Instruments iii Specific Model Information Instrument Serial Number _______________________ Instrument Range _______________ Calibrated for _____________...

Page 4: ...and or damage the instrument CAUTION HOT SURFACE WARNING This warning is specific to heated components within the instrument Failure to heed the warning could result in serious burns to skin and unde...

Page 5: ...his manual and keep it available Occasionally some instruments are customized for a particular application or features and or options added per customer requests Please check the front of this manual...

Page 6: ...5 Model Identification 4 Installation 5 2 1 Unpacking the Instrument 5 2 2 Mounting 5 2 3 Wiring 7 2 3 1 Site Wiring 7 2 3 2 Power Wiring 7 2 3 3 Sensor Wiring 8 2 3 4 DC Power 8 2 4 Configuring the L...

Page 7: ...Output Calibration 26 4 10 Locus Calibration 27 4 11 Temperature Calibration 27 4 11 1 Temperature Adjustment 27 4 11 2 Temperature Calibration Manual TC Adjustment 28 4 11 3 Temperature Units Calibr...

Page 8: ...Figures Figure 1 1 LXT 280 User Interface 3 Figure 2 1 Typical Installation for the LXT 280 Transmitter 6 Figure 2 2 Intrinsically Safe Wiring Diagram 7 Figure 2 3 LXT 280 Wiring 8 Figure 3 1 LXT 280...

Page 9: ...ytical Instruments ix List of Tables Table 5 1 Oxygen Saturation vs Temperature 32 Table 5 2 Relative Humidity Correction Factors 33 Table 5 3 Elevation Correction Factor 33 Table 5 4 Salinity Correct...

Page 10: ...tible gases are being analyzed since the potential of gas leaks always exist The customer should ensure that the principles of operating of this equipment is well understood by the user and that the i...

Page 11: ...ic Ion The standard instrument is powered from an external 24 VDC source and is equipped with a 4 20mA current output transmitted on the same 24 VDC wiring The power supply and electronics are remote...

Page 12: ...g The current output is fully expandable to any range within the transmitter s full operating range The current output can be configured to be reverse acting Temperature Conversion Temperature can be...

Page 13: ...ic switch arrow keys that control the operation of the unit Figure 1 1 LXT 280 User Interface The keys are in two groups VERTICAL UP DOWN Arrow Keys These keys are used to change the display menu They...

Page 14: ...horizontally 1 5 Model Identification The LXT 280 Transmitter is a 24VDC unit The instrument is configured at the factory for the customer s application and so there are many different model designat...

Page 15: ...er as proof of mishandling for the carrier 2 Check the contents of the shipping container with the items and quantities shown on the packing list Immediately report any discrepancies to TI TAI 3 Save...

Page 16: ...ONLY FM APPROVED SAFETY BARRIERS CONTACT TELEDYNE FOR A LIST OF FM APPROVED INTRINSIC SAFETY BARRIERS FOR YOUR APPLICATION If mounting hardware is ordered with the instrument it has been factory assem...

Page 17: ...your local plant safety engineer based on State and Federal requirements 2 3 2 Power Wiring For power wiring the LXT 280 transmitter requires a nominal 24 VDC voltage source With zero loop impedance t...

Page 18: ...sensor or electrode to the LXT 280 transmitter for proper operation Teledyne models SP 1 and SP 2 sensors will provide the required conditioning Figure 2 3 illustrates the proper wiring of the sensor...

Page 19: ...on the application Among other things the calibration routine establishes the correspondence between the 4 20 mA output signal and the application dependant measurable parameter Calibration can be pe...

Page 20: ...Installation LXT 280 Teledyne Analytical Instruments 10...

Page 21: ...ey are magnetic and are operated by touching the glass in front of the appropriate key using the supplied magnetic screwdriver This allows instrument operation without having to open the cover and exp...

Page 22: ...the left These keys are also used to move the cursor horizontally 3 2 Menus The LXT 280 contains a series of menus from which different functions can be accessed You can scroll through all available...

Page 23: ...in percent instruments while white screens apply to dissolved oxygen in ppm instruments When only one screen is illustrated the screen is applicable to both instruments 3 2 1 Contrast Display contras...

Page 24: ...s not compensated for temperature variations This value can be used to determine the saturation limit of the sensor and the maximum effective range of the instrument with that sensor and electrode For...

Page 25: ...n is helpful in determining the quality of the dissolved oxygen electrode In conjunction with regular calibrations the Electrode Data Screen can provide valuable information to track electrode service...

Page 26: ...be adjusted in this menu The 4 mA and 20 mA points may be defined in percent dissolved oxygen or parts per million dissolved oxygen depending on the software installed in the transmitter The maximum a...

Page 27: ...re Calibration Menu This screen has two calibrate functions and a conversion function It is used to adjust or trim the temperature compensation for variations in the sensing element It is also used to...

Page 28: ...Operation LXT 280 Teledyne Analytical Instruments 18...

Page 29: ...ro calibration step 1 periodically to check for drift and whenever a new sensor is installed It may be useful to set the contrast of the display prior to calibration to compensate for current lighting...

Page 30: ...rrow key until the cursor is under the M As long as the M is in front of the output the current output of the transmitter will be held at that filed value To release manual output 1 Return to the Main...

Page 31: ...amplifier from one sensor to the next the zero point may differ In some cases especially in low ppm measurements a zero calibration may be desirable Two zero calibrations are possible with a dissolved...

Page 32: ...after the zero calibration 4 5 Span Calibration The span calibration is typically the only calibration that needs to be performed on a routine basis This calibration compensates for changes in the me...

Page 33: ...activating the appropriate VERTICAL arrow key 7 Wait for the real time mV value to stabilize 8 To file the calibration and exit the calibrate mode magnetically activate the LEFT HORIZONTAL arrow key...

Page 34: ...te the RIGHT HORIZONTAL arrow key to enter the calibrate mode 4 Wait for the real time mV to reach its minimum value zero calibration or wait for the real time mV value to stabilize span calibration 5...

Page 35: ...shortened span of the electrode in service In order to obtain ideal system calibration a span calibration is required The following procedure for returning the LXT 280 back to factory calibration can...

Page 36: ...20 mA range use the following procedure Procedure 1 Magnetically activate the appropriate VERTICAL arrow key to reach the Output Calibration Menu 2 Position the cursor on the top line to change the 4...

Page 37: ...he HORIZONTAL arrow keys position the cursor under the digit to be adjusted 4 Increase or decrease the value by Magnetically activating the appropriate VERTICAL arrow key 5 To file the locus value and...

Page 38: ...the RIGHT HORIZONTAL arrow key to enter the calibrate mode Observe the cursor move under the last digit 5 Position the cursor under the desired digit using the left HORIZONTAL arrow key 6 Increase or...

Page 39: ...on the bottom line read the process temperature Note Make temperature adjustments slowly to allow time for the bottom line on the display to update This can take 5 to 7 seconds 4 11 3 Temperature Uni...

Page 40: ...Calibration LXT 280 Teledyne Analytical Instruments 30 Trim 0 Unit 25 0 C Trim 0 Unit 77 0 F...

Page 41: ...To correct for these factors refer to the tables below Please note that the tables only apply to absolute dissolved oxygen measurements those in ppm or mg l and not to relative dissolved oxygen measur...

Page 42: ...0 3 Determine the relative humidity if performing the calibration in air only If calibrating in an air saturated sample assume a relative humidity of 100 4 Referring to Table 5 2 Relative Humidity Cor...

Page 43: ...0 986 981 975 967 70 996 994 992 988 984 978 971 961 80 995 993 990 987 982 975 967 956 90 995 992 989 985 979 972 962 950 100 994 991 988 983 977 969 958 945 Table 5 3 Elevation Correction Factor Ele...

Page 44: ...Table 5 1 If the temperature of the sensor and value used from Table 5 1 are not the same an error will be introduced into the calibration 5 2 Salinity Correction When seawater brine or brackish samp...

Page 45: ...ature of 30 C the relative humidity correction factor is 0 958 3 Determine the elevation correction factor CFE from Table 5 3 At 1 500 feet the elevation correction factor is 0 947 4 Determine the sal...

Page 46: ...asurement are typically found in applications where saturated oxygen must be controlled for a chemical reaction or where the presence of saturated oxygen is detrimental to the process Another unit of...

Page 47: ...he integrity of the enclosure seals should be inspected Also check the conduit fittings and seals to make sure moisture does not enter the enclosure while cleaning If the enclosure cover must be remov...

Page 48: ...itter Check the sensor for proper operation To verify disconnect all sensor wires and cycle power off then on Sensor not wired properly Using the proper wiring diagram verify that the sensor is proper...

Page 49: ...ronically then recalibrate per Section 4 Membrane is coated Clean the membrane See Sensor manual Slow Response Protective Boot was left on the front of the sensor Carefully remove the protective boot...

Page 50: ...Signal conditioner not properly engaged in the rear of the sensor body Verify that the signal generator is properly engaged in the rear of the sensor body Temperature trim not properly adjusted Verify...

Page 51: ...le Maximum 3 outputs Max Loop Impedance 525 ohms for 4 20 mA compliance Power Supply Relay Module Optional 115 230 VAC 50 60 Hz 0 5 A 2 ea Form C SPDT dry contacts 5 0 A Display Menu driven 32 alphanu...

Page 52: ...ions 8 7 cm x 12 5 cm Calibration Auto Buffer Calibration Allows definition of two buffer points saved in memory during the initial startup This allows subsequent zero and span calibrations with only...

Page 53: ...unting Bracket 1 ECD 9680066 U bolt 2 x 3 1 2 304 SS includes nuts and washers 1 ECD 9680069 Terminal Screw and Clamp Assembly set of 9 1 ECD 9680044 1 Instrument Screwdriver with Magnetic Top Note In...

Page 54: ...44 the instrument for which the parts are intended Orders should be sent to TELEDYNE Analytical Instruments 16830 Chestnut Street City of Industry CA 91749 1580 Phone 626 934 1500 Fax 626 961 2538 Web...

Page 55: ...ay contrast See contrast dissolved oxygen 1 dissolved oxygen unit 36 DO locus menu 16 effective range 14 15 electrode 8 14 electrode data screen 14 electrode degradation 23 electrode output 14 electro...

Page 56: ...volt value relative dissolved oxygen 31 relative humidity 32 relative humidity correction factor 33 relay module 41 release manual mode 20 resistivity 1 response time 41 reverse acting 2 routine maint...

Page 57: ...Analytical Instruments 47 wall mount 5 warning sign iv warranty ii weather proof enclosure 41 web address 44 website address v window 2 11 Winkler analysis 22 zero calibration 15 19 21 zero electrode...

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