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Valco baby Vici TCD-3, Инструкция по эксплуатации

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20

Initial Bakeout and Equilibration

Balancing the Channels

The output channel voltage levels vary greatly depending upon factors such 
as temperature, filament power, gas concentration, pressure, flow rate, etc.  Due 
to these factors, the TCD-3 output channels must be periodically leveled, which 
adjusts their output state to a desired voltage level (typically 0 Volts).

As the filaments are very sensitive, this adjustment can only be done within a 
thermally stable system, indicated by the Detector Status LED glowing bright 
green.  Stabilization can take several hours when starting from a cold detector.

Once the system is stable, press the Zero A button to calibrate the Channel A out-
put to the preset voltage level for that channel.  When that process is complete, 
press the Zero B button to repeat the process on that channel.   
The system is now calibrated.

Figure 11:

  Approximate Filament Temperature vs. Filament Power Setting

Содержание Vici TCD-3

Страница 1: ...CD 3 Valco Instruments Co Inc 800 367 8424 sales 713 688 9345 tech 713 688 8106 fax valco vici com VICI AG International Schenkon Switzerland Int 41 41 925 6200 phone Int 41 41 925 6201 fax info vici ch North America South America and Australia Oceania contact Europe Asia and Africa contact ...

Страница 2: ...This page intentionally left blank for printing purposes ...

Страница 3: ...omponent Dimensions 9 Detector Mounting 10 Vertical Mounting 10 Horizontal Mounting 11 Gas Connections 11 Installing and Purging the Gas Regulator 11 Installing and Purging a Purifer 13 Column Connection 13 Referenced Mode 13 Unreferenced Mode 13 Packed Columns 14 Packed Columns with Swagelok type Female Nut 14 Capillary Columns 14 Testing for Leaks 14 Cable Connections 15 Heater and Filament Conn...

Страница 4: ...igital Signal Inputs 31 Digital Input Functions 31 Digital Output Signal 31 Appendix B Basic Control of the TCD via Serial Commands 32 Establishing Serial Communication 32 Initial Bakeout and Equilibration 33 Initial Conditioning 33 Temperature Settings 33 Balancing the Channels 33 Serial Communication Protocols 34 General Console Port Usage 34 Interface Command Editing 34 Serial Commands 35 Appen...

Страница 5: ...utput signals ranging from 1V to 1V The two signals are identical other than the 1 10 voltage scaling A third channel Channel AB is the referenced or differential output derived from the difference of the two filament energy states i e Channel A Channel B Operating Principle The principal of operation is based on the relative change in the thermal conduc tivity of the gas passing across the detect...

Страница 6: ...he rear on the unit and through the RS 232 communication port After the detector has reached thermal stability with constant carrier gas flow the filament channels of the detector achieve a low drift low noise operational state Measurements of the energy states of the detector filaments are avail able from the controller s three analog output channels Output Channels A and B reflect the energy sta...

Страница 7: ... of the power inlet The instrument operates with a DC power cord having a protective earthing shield conductor This shield ring must be connected to an earth ground either by direct connection or through the external power supply module Any such power supply module must have a mains line plug in serted in a socket outlet provided with a protective earth contact The protective action must not be ne...

Страница 8: ... 1 Controller unit TCD3 C 1 Power supply 120w AC DC 48 V I 25850 1 Power supply cord 115 VAC I W 17600 230 VAC I W 17850 3 Analog output cables I 25487 1 RS 232 cable I W RS232 4K 1 Digital I O connector I T1790124 1 Fittings kit TCD3 KIT Includes 2 1 16 zero dead volume union ZU1C 2 1 16 zero dead volume nut ZN1 2 1 16 zero dead volume ferrule ZF1 2 Fused silica adapter for 0 8 mm OD capillary co...

Страница 9: ...een toggle fast Parameter save in progress do not power off unit Fast red blink Detector cell not found Fast green blink Auto zeroing operation in progress Red green alternating Auto zeroing function failure Green w red flash Output channel s off scale Steady red Hardware initialization failure Table 2 Status indicator explanations Make sure the ON OFF switch is in the OFF position when making pow...

Страница 10: ... an internal signal reference at zero volts For best noise performance the shield earth and signal reference should not be connected together Hardware Specifications Parameter Minimum Nominal Maximum Units Notes Controller input voltage 44 48 52 V Controller input current 0 1 1 5 A Vin 48 Vdc Input fusing 2 0 A Internal fuse time delay type Operating Temperature 10 40 C Storage Temperature 25 70 C...

Страница 11: ...rrier the purest carrier available must be used in order to achieve the lowest possible detection limit To maintain carrier purity extra care must be taken to assure that the delivery system is clean and free of leaks Use stainless steel tubing cleaned to removed manufacturing solvents instead of nylon or PTFE tubing which can diffuse contaminants into the carrier GC Column Selection Cell volume h...

Страница 12: ...hile nitrogen is only 26 0 Argon is even lower at 17 7 Since the largest difference in thermal conductivity yields the best response detection of small amounts of hydrogen is better done with argon or nitrogen carrier than with helium However while nitrogen as a carrier yields excellent response to hydrogen the response to oxygen and carbon dioxide is diminished compared to the levels that could b...

Страница 13: ... Do not shut off or disconnect the carrier gas when the detector is hot even if the unit is turned off Turn off the power switch on the back of the controller and allow the detector to cool down naturally before disconnecting or shut ting off the carrier gas Position the controller unit where the power switch on the rear panel can be reached easily Component Dimensions Figure 3 TCD 3 controller di...

Страница 14: ... the TCD 3 can usually be set in its place If not use a drill or chassis punch to make a hole of the proper size and set the detector in position While trying to match base plate mounting holes to every GC on the market is impractical the mounting holes for the TCD 3 have been located so that at least two of them should align with existing holes on the GC Figure 5 Orient the detector to allow for ...

Страница 15: ...as connections for a typical TCD 3 detector system in unreferenced Figure 6 and referenced Figure 7 modes Installing and Purging the Gas Regulator 1 Make sure the on off valve on the carrier gas cylinder is completely closed Screw the CGA fitting nut of the regulator into the gas cylinder Go beyond finger tight but do not tighten the nut all the way some leakage is required for the purging operati...

Страница 16: ... Figure 6 TCD 3 plumbed for operation in unreferenced mode Figure 7 TCD 3 plumbed for operation in referenced mode A B CAUTION Never use leak detecting fluids on any part of the TCD 3 system Installation ...

Страница 17: ...ot available tighten all the fittings including the output pressure gauge and repressurize the system for another test 7 Uncap the outlet tube of the purifier and purge the system for 15 to 30 minutes at 60 to 80 mL min to eliminate air from the purifier getter material Column Connection To prevent detector contamination it is strongly recommended that the column be disconnected from the detector ...

Страница 18: ...uires a union which adapts the female nut to the Valco fitting Capillary Columns Connection of these columns requires the use of the ZU1C with the appropriate fused silica adapter For a 53 mm ID x 8 mm OD column use the FSR1 8 supplied with the TCD For other sizes use this table to determine the proper adapter ZU1C with fused silica adapter Column size 32 mm ID x 5 mm OD 25 mm ID x 4 mm OD 2 mm ID...

Страница 19: ...y into place Pin assigments are indicated below Data Output Cable s Connect the data output cable s The A B A B outputs are typically used with an integrator or PC based data acquisition system Polarities and full scale range are indicated in Figure 8 Set the recorder DAQ for the same voltage scale Serial Data Extension Cable The TCD 3 connects to a PC laptop via a RS 232C connection The provided ...

Страница 20: ...ctor can be operated at extremely low flow rates less than 0 5 mL min without damage to the filaments 1 Measure the column flow at the detector s Channel A out The optimum flow rate is in the range of 4 20 mL min with the actual rate dependent on the type of column used 2 Measure the reference gas flow at Channel B out It should be as close as possible to the GC column flow Use a fixed flow restri...

Страница 21: ...cally install two programs in addition to the TCD GUI LabView 2013 Runtime Engine and LabView VISA Runtime Engine applications from National Instruments which are required to run the GUI Establishing Communication 1 With carrier gas still flowing turn on the TCD controller with the on off switch on the rear panel 2 Find TCD 3 Control GUI on the Windows Start menu and click to open it After the spl...

Страница 22: ...rt 6 If the COM Port Selection setting is changed press the Re Initialize COM Port button to re establish the communication link Once communication has been established with the unit the information fields in the System Status and System Info boxes will be filled in Figure 10 Configuration screen BRight green light indicates proper communication between the computer and the TCD controller when a d...

Страница 23: ... detector temperature Refer to Figure 11 which outlines the relationship between the filament power settings and the actual filament temperature Detector sensitivity increases as the temperature differential between the detector and the filaments increases howe ver the lifetime of the filament decreases as its temperature increases Thus the detector temperature should be set as low as possible det...

Страница 24: ...olts As the filaments are very sensitive this adjustment can only be done within a thermally stable system indicated by the Detector Status LED glowing bright green Stabilization can take several hours when starting from a cold detector Once the system is stable press the Zero A button to calibrate the Channel A out put to the preset voltage level for that channel When that process is complete pre...

Страница 25: ...so has simple controls for auto leveling the output channels 1 Unit Status LED Red The selected COM port could not be opened Dark green The selected COM port opened but cannot establish good communi cation with the TCD 3 Light green Communication is good the unit is functioning correctly and the output status is good Yellow Communications are good but there is an issue with the unit Typically this...

Страница 26: ...he relationship between the fileament power setting and the filament temperature 12 Filament Power Chan B input field Enter the desired Channel B filement power setting here Refer to Figure 11 on page 20 to view the relationship between the fileament power setting and the filament temperature 13 Zero A Zero B and Zero A B buttons Click the appropriate button to calibrate the Channel A B or A B out...

Страница 27: ...shed Then it will display one of the messages below Detector not found The detector unit was not sensed by the TCD 3 controller Check that the detector unit is connected to the controller and that both cables are fully seated in their sockets Temperature not yet stable The detector has not yet reached full temperature stability Note that the minimum time to stability is 30 minutes Detector stable ...

Страница 28: ...n the TCD control ler and the computer If it is not on refer to Establishing Communication on page 17 11 Comm Link info box This field indicates the current status of the communication link between the PC and the TCD controller Port not initialized This is displayed before the user tries to establish the com link Could not open COM port The software could not open the port Either the selected port...

Страница 29: ...s for both Channels B and AB are set to 0 8V an auto adjustment request for Channel AB would be impossible as Channel A would have to be set to 1 6V to meet that requirement and the maximum adjustment range is 1 0V 15 Target Accuracy indicator and input field Read or set the minimum accuracy required for completion of any output level adjustments initiated by clicking the Zero A Zero B or Zero A B...

Страница 30: ...chronize Controls button The Resynchronize Controls button forces the GUI software to re read all the settings and states from the TCD 3 controller and update the software s indica tors to match This is automatically done when communication is established and should not generally be required but the function is included as a utility Graph Screen The Graph screen Figure 14 is used to monitor the un...

Страница 31: ... three axes on the graph are Output Channel vertical axis left side Block Temperature vertical axis right side and Graph time horizontal axis Select each of these in turn to enter relevant parameters in item 12 Two of the three examples are shown in the example 11 Autoscale check box When the Autoscale box is checked the graph will automatically adjust the axes to best fit the data points in the w...

Страница 32: ...VICI technical sup port for assistance Fast red blink Detector not found If the TCD 3 controller cannot detect that a TCD3 NIFED or similar detector is connected the status LED will blink red at a fast rate Check that the detector cables are properly connected Fast green blink Auto leveling in progress When an auto zeroing operation is in progress the status LED blinks green at a fast rate Slow gr...

Страница 33: ...ken in its use Bake Out Procedure Under normal conditions the TCD 3 requires no routine maintenance How ever if the detector is exposed to chemicals which may condense or polymerize within the detector and adversely affect performance the detector cell can be baked out at elevated temperatures up to 300 C Inert carrier gas flow other than hydrogen oxygen or air should be maintained during the reco...

Страница 34: ...nput signals and one digital output signal Pin Signal Pin Signal 1 Digital Input 1 5 Input Signal Ground 2 Digital Input 2 6 Input Signal Ground 3 Digital Input 3 7 Input Signal Ground 4 Digital Output contact A 8 Digital Output contact B Table 9 Digital I O port pin assignments Digital IO Connector The TCD 3 system includes a removable plug for use with the Digital I O port equipped with attached...

Страница 35: ...utput Channel B to its saved target voltage level set through the COM port using the ZB command The TCD 3 controller will then adjust output Channel AB to its saved target voltage level set through the COM port using the ZR com mand The process triggered from this digital input is identical to the console command ZS Digital Input 2 Reset error flags When Digital Input 2 is activated i e driven to ...

Страница 36: ...ommunication With the software running turn the On Off switch on the controller to the ON position If the link is functioning the following welcome message will appear on your monitor This message lists the unit designation the firmware and hardware revisions and the unit serial number Valco Instruments Company Incorporated Thermal Conductivity Detector Version 3 Firmware revision 1 0 0 Hardware r...

Страница 37: ...ssible determined by the boiling point of the highest boiling component of the sample 9 Once all temperatures are set allow plenty of time for the system to equilibrate evidenced by a stable baseline Typical equilibration time for going from a cold start up to 130 C detector temperature is approximately five hours Detector temperature changes take much longer to equilibrate than do filament temper...

Страница 38: ...y characters on the input line after the final valid parameter are ignored Multiple commands may be issued on a single command line The commands must be separated by a semicolon character These commands will be processed and implemented in a single parsing cycle and thus will become effective simultaneously A maximum of 80 characters are permitted in a single command line Interface Command Editing...

Страница 39: ... heater and filaments Output level adjustment ZA volts Adjusts channel A to the default voltage level or to the value specified ZB volts Adjusts channel B to the default voltage level or to the value specified ZR volts Adjusts channel A B to the default voltage level or to the value specified ZS Initiates an adjustment sequence channel B then channel A B PF Reads sets the minimum accuracy of the a...

Страница 40: ...5 Ω 25 Ω open open open open open B3 FIL B open SHORT 25 Ω 25 Ω open open open open open B2 FIL B open 25 Ω 25 Ω SHORT open open open open open B1 FIL B open 25 Ω 25 Ω SHORT open open open open open A5 n c open open open open open open open open open A4 FIL A open open open open open open SHORT 25 Ω 25 Ω A3 FIL A open open open open open open SHORT 25 Ω 25 Ω A2 FIL A open open open open open open ...

Страница 41: ...er devices to the goods This Limited Warranty does not cover expendable items This warranty is VOID when repairs are performed by a nonauthorized service center or representative For information about authorized service centers or representatives write Customer Repairs Valco Instruments Company Inc P O Box 55603 Houston Texas 77255 or phone 713 688 9345 At Seller s option repairs or replacements w...

Страница 42: ...38 Detector Performance Log ...

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