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Series 8800 - Trace Moisture Analyzers
How do I reset the LOc, Un/LOc feature? If a power on / off switch is available: 1) Turn off power 2) Hold down the mode switch while powering up 3) Use the mode switch to scroll through the menu until you find the 'Set loc unloc' screen 4) Use the up or down key to select loc or unloc 5) Press the mode button to return to the normal dewpoint display If there is no power switch: 1) Press the mode switch to get to serial number screen (SEN) 2) Press and hold the up and down keys simultaneously for a few seconds 3) The start-up screen will be displayed 4) Immediately press the mode button to see Set Alt and DSP 5) Press the mode button to scroll through the menu to the 'Set loc unlock' screen 6) Use the Up or Down keys to select between loc or unlock Top of page What are the warnings and error messages for these instruments? Please view the following pages from the manual. (PDF file). Top of page In the portable unit, does it automatically turn itself off after some time? If so is there a way to defeat this feature? The model 8800P operating on a battery will turn off after 6 minutes when in the measuring position, or 3 minutes when in the dry position. Of course this feature is intended to save the battery, and it cannot be defeated. For model 8800P with RS-232 and wall transformer option the auto-turn-off can be defeated by plugging it into the wall AC power (the higher voltage defeats the auto-turn-off), or by shorting pins on the DB9 connector. Top of page Is this within specifications? Yes, it is. The specified response time of the unit is for a step change from -40 to -60 Deg C is 90% in 450 seconds. That is 7.5 minutes for the first 90%. Obviously the next 10% will take longer. Response time for areas outside of this specified range can be longer. At -90 to -70 Deg C, the user is looking at the response at the very low end of the sensor range, where the response time would be greater. At constant temp. and pressure, -90 degrees C is equivalent to less than 1 ppm moisture. This is instrument is not suitable for PPB level measurements. Top of page Regarding the Intrinsic Safety sensor barrier, how do we do the sensor cable compensation? Connected or disconnected? (The sensor cable connects to pin5 and pin6 directly.) And what is the limit of the cable length or its impedence in ohms? Any instrument and cable and barrier combination purchased and shipped from the factory as a set is already properly compensated. One would only need to perform sensor cable compensation if the cable or the barrier is changed or added. When a compensation is performed, the hookup has to be identical to the way it will be used. The sensor has to be unplugged at the end of the cable. That same end where the sensor is plugged in (refer to attached control drawing - the cable end is where a dark rectangle labeled Intrinsically Safe Apparatus see Note F), needs a temporary means of shorting or opening the cable, then follow the instructions in the user's manual. We have installed systems with up to 1000m of RG6 cable. Top of page In the measuring mode, the displayed dewpoint value is 330ppm when the sensor barrier is connected. And the displayed dewpoint value changes to 8700ppm when the sensor barrier is disconnected. So, which displayed dewpoint value is the correct one? And why? If the (analyzer - cable - barrier - sensor) combination were shipped from the factory as a set, then the correct reading is 330ppm. Top of page When we set the dewpoint corresponding to the low end and high end of the analog output, we want to know the ppm values corresponding to -100, -90, -80,-30,-20 degrees centigrade. And what is the calculation formula for degrees centigrade to ppm exchange. Formulas are difficult to compute, therefore Teledyne has come up with the moisture calculator program to download and run for this calculation. Top of page What is the RS-232 configuration on the 8800P? 9600 Bits per second, event parity, 8 data bits and 1 stop bit. This is reported incorrectly in some versions of the device manual which have the data bits at 7, however, 8 is the correct number. Top of page All indicators are blinking. What do I do? Switch on instrument Scroll with Mode button to Serial Number Hit Pressure Correct button (this will jump to Set-up Mode). You will now see Alt/dSP Use mode button to Scroll to LoC Use Units-Up to toggle display to Un/Loc (this will unlock the instrument) Use Mode button to scroll to Alt/dSP Use units button to select ?blank?. You want no alternative display at all. This is achieved when only Alt/dsp is blinking and in the upper left hand corner There is the word ?SET? Use Mode key to scroll to Un/LoC Use Units-Down to toggle to LoC (this will lock the instrument) Hit Pressure Correct. This will transport you back to operating mode. The display will no longer blink. Please refer to Appendix B of the manual on page 37. Top of page What is the most likely source of a problem with the 8800 series? Generally speaking, most of the problems that arise with the use of the 8800 Series moisture units arise due to substandard sampling techniques. The H2O molecule is sticky, and takes a long time to purge out of interconnection tubing, and the other components that separate the sensor from the process being measured. For us to best understand the problems you are having and recommend a solution, we would appreciate it if you could provide us the following: a) a complete description of the gase(s) that you are measuring the H2O in b) a digital picture of the setup c) a complete description of every component used in the setup, with particular attention to the wetted materials used d) a description of the problem you have Top of page What do we do when our 8800 stops performing at its best? 1. It is recommended that the XTR sensor be returned to Teledyne for recalibration every 12-18 months. The cleaner the gas, the longer it should take between recalibration intervals. The dirtier the gas stream, the shorter the intervals. 2. A fee will be charged to determine what's wrong with the unit. This evaluation rate is the same if you return just the sensor or both the electronics and sensor. 3. In the case of the 8800A (panel mount) and 8800B (wall mount), you may return either just the sensor, or both the sensor and electronics. If you return just the sensor, these are the likely options: a. Order a new sensor b. Wait for their original sensor to be returned and recalibrated. You will be required to enter the calibration coefficients / test points, provided in the calibration certificate, into the software via the mode menu on the unit. 4. In the case of the 8800P (Portable) and 8800T (Transmitter) you must return the complete unit for recalibration. Notes: 1. When the unit is first provided, the sensor comes threaded to a desiccant container to keep the XTR sensor free from exposure to moisture. Keep this desiccant container, as it will be re-used to return the sensor to TAI for recalibration. 2. If the senor is broken in half, is saturated with oil, is corroded or has a foul smell (i.e., from exposure to H2S, etc), the sensor should not be returned for eval / recal purposes. Simply replace the sensor with a new one. Top of page I can't seem to purge the 8800. Is this due to the copper tubing I used for the sample system? The reason copper tubing should not be used is most likely related to ability of the copper tube to absorb moisture molecules. The finish of the copper tube is such that it will absorb / desorb moisture continually and it cannot be successfully purged. Please switch to stainless steel tubing. Top of page How do I keep the engineering units displayed on one selection? The unit has to be unlocked in order to change engineering units permanently. This is to protect installations in the field from engineering units being inadvertently altered, which will result in a change of the output signal, without the DCS system knowing. When the unit is locked, you can use the UP and DOWN keys display values in other engineering units, but the display will automatically switch back to the units that were selected when the instrument was locked; and the signal output never changes. To unlock the instrument refer to the manual. Start the instrument in Set-up mode (hold down MODE key while powering the instrument up), use mode button to scroll to the Loc/UnLoc mode, hit the UP arrow key. Switch the instrument off and on again; its now unlocked. Top of page We need to change the s-1272-replacement sensor element XTR65 on our 8800T. Can you tell us how? The sensor is replaced by unscrewing the old sensor from the transmitter. Please see the diagram in the sensor installation section of the instruction manual on page 34. Top of page Can teflon tubing be used to connect the sample to the instrument? Yes, but dewpoints may only go down to -60C or so because of permeability from air of the tubing and leaks at the connections. For the highest integrity measurments, use electropolished stainless steel tubing and stainless steel connectors. Top of page What is the appropriate set point for the 'gas pressure' and 'the sensor pressure'. Should the set point be at the pressure of the line where the 8800A is installed (3.7 kgf/cm2 g), or at the highest pressure in the system which is protected by the analyzer -- about 29 kgf/cm2 g)? For example, in this application, if we use 30 kgf/cm2 g (the highest pressure within the unit) as the 'Gas Pressure', and the dew point indicator show us that the dew point is -85°C, then we can be sure that hydrate won't be formed in any other point within the unit (because the pressure in any other points within the unit is lower than 30 kgf/cm2 g) as long as the unit is operated at temperature above -85°C. But if we use - let's say - 3.7 kgf/cm2 g as the 'GasPressure', then even if we are sure that the hydrate won't be formed at the points which pressure are at 3.7 kgf/cm2, but we won't be sure if the hydrate has already formed at another point where the pressure is 30 kgf/cm2. For correct results, the instrument should know the pressure at which the sensor measures. Therefore, it is best that the pressure at which the sensor measures is regulated to be fixed, and we usually recommend atmospheric pressure. When measuring at atmospheric pressure, the SENSOR PRESSURE should be set at 1kg/cm2 (14.5psi). If the sensor is installed at 3.7kgf/cm2, then the SENSOR PRESSURE should be set at 3.7kgf/cm2 (53.7psi). We assume that the 3.7kgf/cm2 pressure is fixed. Use the PRESSURE CORRECT function of the instrument to set the LINE PRESSURE at 29kgf/cm2 (420psi) to obtain the pressure dewpoint. You can use the ALTERNATIVE DISPLAY function to alternate between the dewpoint at SENSOR PRESSURE and the dewpoint at LINE PRESSURE. Top of page What type of wetted materials do you recommend for a flowmeter for low ppm measurments of H20 in front of the sensor? It should be stainless steel fittings with a glass tube. However, it is better to measure flow after the measurement. No matter how good a flow meter, the surface area of sealing surfaces is increased. Water can diffuse directly across the o-rings and seals which will cause trouble with the measurement. Top of page Our 8800A reads +20oC in amb. air. However, it reads -101oC less than 5min after we input N2. And it shows "OPN" on the display. Please advise what the problem is and how to do. The open message means that either the sensor circuit has opened or that the capacitance level of the sensor has dropped to a very low level. There is a programmed set point in the software that if the capacitance drops below a certain point, it assume the sensor circuit has opened. The end user should run the auto calibration as per section 3.4.4.3 in the manual. Before starting the procedure, they should verify that the low dew point and low db values on the sensor bottle are the same as the points in the unit. This is done in the alternate display mode. Again I will also stress the point that the sensor should not be left in ambient air. If the ambient dew point is very high it can cause problems. The manual calls out not to leave the sensor in room temperature air for more than 1-2 minutes. The assumption is that room temperature will be roughly 70-75F with a dew point not much greater than 20 C. The sensor can withstand higher temperatures but the real issue is the humidity level. High humidity will cause a long dry done period but if condensation forms, the sensor can be damaged. When the word ambient gets used and the sensor shows saturated (+20 C), condensation becomes a concern. Ambient conditions in the Middle East are not a concern but ambient conditions in Southeast Asia can be a problem. Top of page Our customer wants their 8800A unit to display readings in ppm levels but Section 3.4.5 of the 8800A manual (p. 25) says the ppm range is only factory settable. The analyser is currently displaying deg C and when the customer changes the unit to ppm the analyser waits for 30 seconds and resets the units to deg C. Are the measurement units are in fact settable at the field? Please advise how we should go about changing the unit to ppm. The Dewpoint reading can be displayed in units of PPM, oC, oF, LBS, or G/M3. By pressing the Up or Down key while in normal operation mode (Viewing Dewpoint mode). This is in section 3.4.4.1 of the manual. The default unit for this analyzer is oC, however, from the keypad this can be changed to PPM or any of the other units, and when changed will be retained until changed again. Page 25 section 3.4.5 covers other Setup states, and changing the viewing dewpoint units is not included in the 4 of 11 modes that are factory set. In this Setup state we are allowed to select an "Alternate display', If ppm were selected in this mode, it will alternate between PPM & oC. (This is most likely what occurred here) To remove this alternate display, they should scroll thru the alternate display units, until they reach the Blank display, this means there is no alternate display. When the blank display is selected, the PPM unit selected in the "Viewing Dewpoint" mode will be the only unit displayed. Top of page |
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Document Control & Training (password) e-mail us: ask_tai@teledyne.com Copyright © 2007 Teledyne Technologies Incorporated. All rights reserved. Teledyne Analytical Instruments • 16830 Chestnut St • City of Industry, CA 91748 • USA |
