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COMPACTGC
Instruction Manual
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Interscience COMPACTGC Instruction Manual

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COMPACT
GC
Instruction manual
version 2.01 (January 2005)
CompactGC Instruction Manual January 2005 Edition © 2005 Interscience B.V., The Netherlands. All rights reserved.
Published by Interscience B.V., The Netherlands, P.O. Box 2148, 4800 CC Breda Tel: +31 76 5411800 Fax: +31 76 5420088
Printing History: First Edition, version 1.04, released July 2003 Second Edition, version 2.01, released January 2005
Disclaimer
Technical Information contained in this publication is for reference purposes only and is subject to change without notice. Every effort has been made to supply complete and accurate information; however, Interscience B.V. assumes no responsibility and will not be liable for any errors, omissions, damage, or loss that might result from any use of this manual or the information contained therein (even if this information is properly followed and problems st ill aris e).
This publication is not part of the Agreement of Sale between Interscience B.V. and the purchaser of a CompactGC system. In the event of any conflict between the provisions of this document and those contained in Interscience B.V. Terms of Delivery, the provisions of the Terms of Delivery shall govern. Reference to System Configurations and Specifications supersede all previous information and are subject to change without notice.
Trademarks
CompactGC is a trademark of Interscience B.V. Other brand and product names may be trad emarks or registered trademarks of their respective companies. Valco® valves is a registered trademark of Valco Instruments Co. Inc. and Valco International. EZChrom® is a trademark of Scientific Software, Inc.
ii
Manufacturer: Interscien ce B.V . Interscience B.V. is the manufacturer of the instrument described in this manual and, as such, is responsible for the instrument safety, reliability and performance only if:
• installa tion
• re-calibration
• changes and repairs have been carried out by authorized personnel and if:
• the local installation complies with local law regulations
• the instrument is used according to the instructions provided and if its operation is only entrusted to qualified trained personnel. The CompactGC should be handled as described in the pre-installation guide “Gaschromatografiesystemen”. Interscience B.V. is not liable for any d amages derived from the non-co mpliance wi th the aforementioned recommendations.
Interscience B.V.
Postbus 2148 4800 CC BREDA The Netherlands tel: 076-5411800 fax: 076-5420088 www.interscience.nl info@interscience.nl
iii
Table of contents
1. Safety 2
2. Installation 4
3. Instrument description 7
3.1 Digital gas supply 8
3.2 Valve oven 10
3.3 Column oven 10
3.4 Detectors 11
4. Pre-concentration Module (PM) 16
5. The CompactGC editor program 17
Command buttons 18 Tab pages 19 Pull down menu’s 22
6. Operation 28
6.1 Column installation 28
6.2 Leak check 30
6.3 Quick start up 31
7. Maintenance and troubleshooting 33
®
Appendix 1: EZChrom
/ EZStart® settings 34
Appendix 2: Electrical connenctions 39 Appendix 3: LED status display 41
Index
1
1. Safety
Safety summary
The following general safety precautions must be observed during all phases of operation, service, and repair of this instrument. Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design, man u f a ct u r e , an d in tended use of this equipment. Interscience assumes no liability for the customer’s failure to comply with these requirements.
Ground the instrument
To minimize shock hazard, the instrument chassis and cabinet must be connected to an electrical ground, using the provided three-pin AC power cable.
Do not operate in an explosive atmosphere
Do not operate the instrument in the presence of flammable gasses or fumes. Operation of any electrical instrument in such an environment constitutes a definite safety hazard. Contact your supplier for purged housings if the CompactGC needs to be applied in an EX classified zone.
Keep away from live circuits
Analytical column and component replacement and internal adjustments must be made by qualified maintenance personnel. Do not replace components with the power cable connected. Under certain conditions, dangerous voltages may exist even with the power cable removed. To avoid injuries, always disconnect power and discharge circuits before touching them.
Do not service or adjust alone
Do not attempt internal service or adjustment unless another person, capable of rendering first aid and resuscitation, is present.
Do not substitute parts (electronics)
Because of the danger of introducing additional hazards, do not install substitute parts or perform any unauthorized modification of the instrument. Contact Interscience Services to ensure that safety features are maintained.
Do not over-pressurize the instrument
See ‘installation’ for maximum allowed pressures.
2
Hot surfaces should be avoided
The CompactGC has heated inlets. Contacting these inlets once they are at operating temperatures can result in inju ry.
The use of hydrogen
The use of hydrogen for feeding the flame in certain types of detectors requires the operator’s extreme attention and the compliance with special precautions due to the hazards involved in the use of this gas. Moreover, the operator shall be present while analyses are run to immedi ately detect any malfun ctioning. Hydrogen is a dangerous gas (when mixed with air it may generate an explosive mixture), particularly when, in a closed area, it reaches a concentration corresponding to its lower level of explosion (4% in volume). For these reasons, before using hydrogen, the following recommendations must be observed:
1. Ensure that all hydrogen cylinders are complying with the safety conditions provided
for their proper use and storage: they must be equipped with suitable safety valves, automatic safety systems and all that is required by current regulations even with regard to safety in sites with danger of explosion or fire.
2. During the connection of hydrogen lines, ensure that the gas feeding inlet is
perfectly closed.
3. Before using the instrument, ensure that the lines designed for hydrogen are
perfectly leak-tight. According to the results obtained, it will be possible to inspect each single section of the pneumatic circuit as pointed out in said paragraph. Should it be necessary to operate in the inside of the pneumatic compartment or column oven, the check shall be carried out with all circuits under pressure. This procedure shall be repeated until all causes of
leakage have been eliminated.
3
2. Installation
Instrument classification
The instrument classification is according to IEC 10.10:
• internal use
• temperature 18 to 30 °C
• maximum relative humidity between 50 % and 80 %
• transient overload in compliance with installation categories II
• pollution level according to IEC 664 (3.7.3) 2
Space requirements
The CompactGC measures approximately: Width : 45.0 cm (without 19” mounting handles) Height : 17.8 cm (4HE; 18.5 cm including sockets) Depth : 54.0 cm (including handles) Weight : depending on configuration, approximately 25 kg
The unit can be placed on a bench, or can be mounted in a standard 19” rack. For installation of the analytical c olumn and for service, the instrument is accessed by removing the top cover.
Ventilation
Depending on the configuration and operation parameters, sufficient ventilation must be available for cooling purposes.
Gasses Connections
All gas connections are 1/16” Swagelok, except for the actuator gas (1/8”).
Pressure
The maximum pressure for all gasses is 500 kPa. For carrier- and detector gas, 300 kPa is recommended. For fastest valve switching, helium is recommended for actuator gas, but air can also be applied (350 kPa). In case of the PDD (Pulsed Discharge Detector), the discharge gas is directly connected to the Helium suppl y via an internal restrictor. A stable 350 kPa He pressure is needed for this application.
Quality
For carrier gas, He 5.0 (N50) is recommended.
4
Demand
Carrier gas: 2-50 ml/min for each anal ysis ch annel , depending on settings TCD: 2 ml/min (reference gas) FID: 30 ml/min H
; 300 ml/min air
2
PDD: 30 ml/min He PID 2 ml/min make-up
Power requirements
The CompactGC requires 220/230V single phase voltage, 50 Hz. With all options installed, the maximum power consumption is 900 VA. In practice, depending on the configuration, the typical power assertion is much lower.
Digital connections
CompactGC Editor
This 9-pole connection is used for RS-232 communication for parameter programming and status readout. Maximum (tested) length is 10 m.
EZChrom
® /
EZStart®
This RS-232 connection is used for the digital detector data in case of the EZChrom
®
/ EZStart ® data system. Maximum (tested) length is 10 m.
Wherever in this manual is spoken about EZChrom for EZStart Note that in case of the EZChrom connections are needed.
®.
®
data system, two RS 232
®
, it is also applicable
Digital output
The GC-ready and GC-Start-out signals are available on this connector. (Start­out is used to start the data system in case of analog data signal). The programmable output bits are also present on this connector. See appendix 2 for more deta ils.
Digital input
Via this connector, the CompactGC can be started and stopped by remote control hardware signals. See appendix 2 for more details.
Figure 2.1 is showing the electrical and pneumatic connections.
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Carrier gas in (1/16” Swagelok )
Mains switch
220V power connec t io n
EZChrom RS 232 connec t or (D sub 9 pole)
Figure 2.1: electrical and pneumatic connections
Split out (1/16” Swag elok)
CGC Editor RS 232 connector (D sub 9 pole)
Detector ga s in 1/16” Swag el o k)
Flash programming
Actuator He-Air (1/8” Swagelok)
Digital output (D sub 15 po le)
Detector out (1/16” Sw agelok)
Digital input (D sub 15 pole)
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3. Instrument description
The CompactGC is a fully digital 19” rack GC, dedicated for fast gas analysis (however analysis of liquid samples is also possible). The instrument uses reliable well-known technique like Valco columns with down sized dimensions, to obtain short analysis times. Typical analysis times are 10 seconds to 2 minutes. The CompactGC editor, a dedicated program for method programming, sets all parameters. The CompactGC is an up to 3-channel instrument, with a choice of four different detectors. The signal of the detectors is available in digital format, for use with the EZChrom form for connection to other data systems. The basic setup of the system is shown in figure 3.1.
®
valves, robust detectors and standard available capillary
®
data systems, as well in analog
detector electronics
digital gas
power supply
control
detectors
Figure 3.1: Basic system
column oven
valve oven
7
The front half of the instrument contains the ‘chromatography hardware’: on the right side the valve oven for (maximum 3) heated valves, in the middle the isothermal column oven(s) (maximum 3), on the left side the detector compartment, for up to 3 detectors. A module for cryogenic trapping, in case of trace gas analysis, can be installed in place of one of the column ovens. On the back half of the instrument, from right to left side, the power supply, the digital gas supply, and detector controllers can be seen.
3.1
Digital gas supply
The gas control of the instrument is fully digital, and can be present in two types of modules:
• Carrier Gas Module (CGM) for carrier gas
• Detector Gas Module (DGM) for detector gasses
CGM
The Carrier Gas Module is a sophisticated carrier gas supply device, which can be operated in the following modes:
• Constant pressure
• Programmed pressure
• Pressure pulse (pressure surge)
Four different gasses can be used: helium, hydrogen, nitrogen and argon. In case of change of carrier gas type, recalibration of the splitflow is needed. Contact your service organization for more information. Hydrogen is not recommended for safety reasons.
Constant pressure
The most common used operating mode is constant pressure, with digital control of the split flow. See figure 3.2.
In this diagram, the constant pressure is obtained by the upper proportional valve and pressure sensor (P). The lower proportional valve and pressure sensor, in combination with a temperature compensated restrictor are controlling the split flow.
Normally, the optimum flow for a certain type of column is the starting point of method development. The needed pressure can be determined by measuring the flow on the detector outlet, of can be calculated using the available flow calculator (CGC editor).
8
Figure 3.2: Diagram CGM
Programmed pressure, pressure surge
These modes of carrier gas control are obtained by programming the targeted parameters using the Run Time Table. See chapter 5 for more details.
If the CompactGC runs out of carrier gas (no inlet supply), the system switches to the Hibernate mode (all flow and temperature channels are set to value 0) and cools down. The GC needs a reboot (mains power switch, or ‘warm reset’ from the CGC editor menu) to return to normal operation.
DGM
The second type of digital gas supply contains two pressure channels, and is therefore used to control two detector gasses, f.i. hydrogen and air in case of FID, or two reference gasses in case of double TCD. In combination with a calibrated, temperature compensated restrictor in the module, constant detector gas flows are obtained. See figure 3.3. The flows needed for proper detector operation are entered using the CGC editor program.
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detector gas in
proportional
valve 1
P
Pressure sensor
Fixed restrictor
(temperature compensated)
capillary column 1
PPM
TCD front
TCD
TCD 1 out
P
detector gas in
(second detector)
Figure 3.3: Diagram DGM
3.2 Valve oven
The valve oven is an independent heated temperature compartment that provides:
• housing for maxi mum 3 Valco
®
valves, for several configurations like injection,
backflush, streamselection, etc.
• heated sample inlet
• housing for sample conditioning (filtering, pressure reducing, etc.)
The oven can easily be accessed for maintenan ce, injection-loop changing, etc.
3.3 Column oven
In the CompactGC, up to three column ovens can be installed. In order not to lose analysis time compared to a temperature programmed run (cooling down phase), the analysis conditions are normally developed on base of isothermal analysis. Therefore the applied ovens are isothermal and highly stable. The three ovens have independent temperature control, so each column operates at its optimum temperature. The standard supplied oven is used for fused silica columns with an internal diameter of 0.32 mm maximum. For wide-bore columns (0.53 mm id), metal columns are advised. The most common used columns are 2-15 meter/0.32 mm id fused silica. In the oven, columns with a winding diameter of 8 cm are installed. These columns can be ordered in this dimension, mentioned diameter. See chapter 6.1 for column installation. Ovens for packed columns are available on request.
but also standard columns are used, after rewinding them to the
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3.4 Detectors
Four detectors are available: Thermal Conductivity Detector (TCD), Flame Ionisation Detector (FID), Pulsed Discharge Detector (PDD) and Photo Ionisation Detector (PID) (available end 2003). Up to three of these detectors can be configured in the CompactGC.
TCD
The TCD is a very widely used detect or for analysis of gases, but in principle all components with different thermal conductivity in relation to the carrier gas can be detected. The response is concentration dependant: a higher column flow or make-up flow results in a decreased sensitivity. This detector is a dual channel microvolume cell with two filaments on constant mean temperature. See figure 3.4.
dual filaments
analysis flow
Figure 3.4: TCD detector
reference fl o w
Operation principle
The filaments are continuously losing heat to the wall of the detectorcell by the thermal conducting carrier gas (see figure 3.5). When a component with a different thermal conductivity compared to the carrier gas pass es the filament, the electronic circuit in which both filaments are integrated (Wheatstone bridge) is adjusting the current to maintain the constant filament temperature. This current change is dependant on the component concentration, and is convert e d to a chromatographic signal that can be handled by the data system.
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capillary column 1
analysis
reference
Figure 3.5: Principle of the TCD
TCD front
TCD
TCD front out
The reference flow is supplied by a Detector Gas Module (DGM), and this flow is also used for make-up gas according figure 3.5. This resu lts in a better peak shape, especially for the higher concentrations, and a less critical column connection. Consequently at the ‘TCD out’ exit both flows are measured together. If the column flow needs to be checked, the reference flow can be switched off for a short time (don’t forget to switch off the filament first). The normal reference flow is 1-2 ml/min. Since the response of the detector is concentration dependant, a higher reference flow results in lower sensitivity.
Operation conditions
Cell temperature: 10-20 ºC above column temperature Filament (bridge) temperature: 20-120 ºC above cell temperature, depending on
required sensitivity Reference flow: 1-2 ml/min Polarity: depending on carrier gas Range: depending on required sensitivity
FID
Operation principle
In gas analysis, the FID is popular for carbon-hydrogen containing compounds, due its high sensitivity, good stability, and wide linear response. The response is mass­dependant, so flow rate does not affect the sensitivity.
In the FID (see figure 3.6), the effluent of the column is mixed with hydrogen, this mixture is burned as it emerges from a metallic jet. This jet acts as one electrode (polarizing electrode), while a metallic collar surrounding the flame forms the second electrode. A potential is applied across the pair of electrodes to accelerate the electrons that are generated during the combustion process of the organic compounds. The resultant ionization current is sent to an electrometer impedance amplifier, and converted into a suitable output signal.
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ignition coil
detector cell
collector electrode
polarized electrode
base body
electrometer
air
hydrogen
flame jet
column
Figure 3.6: Diagram of the FID
The hydrogen is mixed with the carrier gas at the column outlet, acting also as a make­up gas. For safety reasons, leakage should be avoided here.
The FID detector cell can easily be removed from the detector base body (it is advised to lower the temperature first). With a special tool, the flame jet too can be removed.
Operation conditions
Temperature: 10-20 ºC above column temperature, minimum 120 ºC, to avoid
condensation of the formed water Hydrogen flow: 30 ml/min Air flow: 300 ml/min
During ignition, the hydrogen pressure is raised by 40 % for easy start of the flame. This is performed automatically when the ignition button is actuated on the related TAB page. The ignition current is switched off after 6 seconds. Note that the ignition state on the TAB page will remain to ‘on’ (since the control program is an editor), so when the flame has to be ignited again (f.i. after the column was changed), first ‘ignite off’ has to be send to the CompactGC, followed by ‘ignite on’.
13
PDD
Operation principle
The Pulsed Discharge Detector (see figure 3.7) is a non-radioactive ionization detector with a universal concentration dependant response. A stable, low power, pulsed DC discharge in helium acts the ionization source. Eluants from the column, flowing counter to the flow of helium from the discharge region, are ionized by photons from the helium discharge above. Resulting electrons are focused towards the collector electrode by a bias electrode.
Figure 3.7: Diagram of the PDD
The principle mode of ionization is photoionisat ion by radiation arising from the transition of diatomic helium to the dissociative ground state. This is the well known Hopfield emission. The photon energy from the diatomic helium continuum is in the range of 13.5 to 17.7 eV.
The PDD is essentially non-destructive (0.01-0.1 % ionization) and highly sensitive. The response to organic compounds is linear over five orders of magnitude with minimum detectable quantities (MDQ) in the low picogram range. The response to fixed gasses is positive (the standing current increases), with MDQ’s in the low ppb range. The detector response is universal except for neon and helium.
Operation
Since the PDD is highly sensitive, also to air, extreme care should be taken to leakages, quality of carrier gas, and all possible sources of detector pollution. Although a helium purifier is used, gas quality should be 5.0 (or N50) or better.
14
To avoid unnecessary gas couplings, the system is directly connected to the gas supply (figure 3.8), which means that the reducer pressure of the gas supply controls the discharge flow. This flow has to be adjusted to 25-30 ml/min (ca. 350 kPa). On the gas exit (vent) of the detector, the discharge flow as well as the column flow is simultaneously present, so for measurement of the discharge flow, the column flow needs to be switched off. The column flow can be calculated by subtracting the discharge flow from the total flow.
customer gas supply
T-piece
fixed restrictor
PDD
reducer
FPM
capillary column
He cylinder
vent
Figure 3.8: GC system with the PDD
After a leak check of this CompactGC channel, and adjustment of the wanted flows, the discharge can be started by the ‘pulser’ button on the related TAB page in the CompactGC editor. The start of the detector is confirmed by a soft high frequenc y sound, and a baseline raise.
Operation conditions
Temperature: 10-20 ºC above column temperature
Discharge flow: 30 ml/min, to be adjusted by external He gas supply regulator (350
kPa)
Range: 64-256 nA
PID
This detector is not released yet.
15
4. Pre-concentration Module (PM)
For trace analysis of gases, sample components can be pre-concentrated using a Peltier cooled micro trap. Contact your local supplier for more information about this option.
16
5. The CompactGC editor program
Since the CompactGC it selves has only two push buttons on his front for starting and stopping the analysis, the CompactGC editor program is used to program all the different GC parameters like temperatures, flow/pressures, detector setting, etc. The CompactGC control program is an ed itor, which means that the different parameters are first only edited on the PC screen; after pushing the SEND button the method­changes are uploaded to the CompactGC and activated. After programming the CompactGC conditions, if wanted, the editor can be closed, and the PC can be disconnected from the PC, since all values are stored in the permanent memory of the CompactGC, and the programmed sequence is carried out independently of the CompactGC editor. When the editor program does remain active during the GC run, all actu al values and status inform ation are displayed to inform the op erator.
When the user starts the CompactGC editor, automatically all configuration and method information is send from the CompactGC to the PC. The configuration data (like number of channels, detectors, etc, a lot of different configurations is possible) is stored in the CompactGC, so the user can see immediately the correct presentation of the parameters of the connected CompactGC.
Figure 5.1: Main window of the CompactGC editor
17
COMMAND BUTTONS
GET METHOD
With this button, the CompactGC editor gets the complete method and configuration information from the CompactGC.
SEND METHOD
The operator pushes this buttons when new entered method-parameters have to be sent to the CompactGC. Only the changed parameters are sent.
STATUS
Besides the actual values displayed at the channel pages, a status window can be opened to display all parameters of the different channels together, also during a GC run. Also status information like run and sequence number, valve positions, etc, is available here.
Figure 5.2: Actual Status display.
18
START – STOP run
These buttons have the same function as both push buttons on the CompactGC. (The instrument can also be started and stopped using the electrical connections on the rear, see appendix 2).
TAB PAGES
FRONT – MIDDLE – BACK Channel
The three possible analysis channels are named front, middle, and back channel. The front channel is in the closest position to the operator and the front of the instrument. Each channel has its own tab-page, which contains all the relevant parameters for one analysis: settings for carrier gas, temperatures, and detector . The set value and actual value are both present. When the operator changes a parameter, always the SEND button has to be used to load the CompactGC with the new information.
AUX
On this page, setting for external devices, if present, are shown.
VALVES
This page is used for test and development purposes. The external events, in most cases valves, can be controlled directly from here. A mouse-click on the wanted event, followed by the SEND buttons activates the choice. In the same way, the additional 8 parallel output bits can also be directly controlled.
RUN TIME TABLE (RTT)
This page controls different actions on time base. The time base is set to zero after each start of the GC run. One of the actions is f.i. the valve command: after each GC start the injection valve is actuated. The following columns are available:
Entry
The entry number of the table.
Time
The time at which an action takes place, after the run is started.
Lock
In order to edit the table in a user-friendly way, related commands can be linked in time. F.i. in case of a fixed time between two different lines in the RTT, for one of these lines a capital ‘A’ is entered in this particular column. For the other line a small ‘a’ is set. When the time for ‘A’ is changed now, the same absolute shift is performed on ‘a’.
19
Sequence
This command is used in combination with the ‘reset sequence counter’ command in the next column of the table, which allows a certain action only to be executed at a selected run number in a sequence. By resetting the sequence counter, a loop is created, that is repeated every time. F.i. in a sequence of 10 analyses, only at run number 1 (needs to be entered in this particular column), a selection valve is actuated for calibration purposes. Another applicat ion is stream selection.
Command
The following actions can be selected in this column:
T set
The temperature of the available devices can be altered with this command on time base
FP set
This command allows you to change flow and pressure settings during the run
Valve
This command is used to activate the external events, mostly valves. Since up to 8 events can be connected, also the valve number has to be entered.
Output bit
The output bit command programs the state of the additional 8-bit parallel output. In case of another data than EZChrom
®
, this command is used to start the data-acquisition. See appendix 2.
Start chromatogram
In case of digital data connection to EZChrom starts the data-acquisition. The use is mandatory in this case.
Autozero detector
During the run, the detector output signal is set to zero using this command. Note that this act io n takes time, and no peaks are allowed to elute during the autozero process.
Detector gain/range
During the run, the detector input sensitivity can be changed in order to detect both high and low concentration peaks in the same sample. This action takes time, so no peaks are allowed to elute during the switching process.
®
, this command
20
Load default method
During a run, the different parameters can be reset to their start (method) values. This is convenient when a lot of parameters have changed, and the original settings are needed during the run.
Reset sequence counter
See the explanation of the sequence column.
End of this run
This command stops the present run of the CompactGC. In case of digital data-collection by EZChrom
®
, the data­acquisition is stopped also. If the number of runs is 2 or more, immediately the next run is started. Since the CompactGC starts his next run immediately, and EZChrom process the acquired data, the EZChrom
®
needs time to
®
runtime should always be shorter than the CompactGC runtime. The time EZChrom
®
needs between runs is dependent on the length of the run, PC processor speed, network connections, etc. Normally 5-10 seconds are appr opriat e.
Channel
If an action can be applied to more than device (temperature, flow, valves), a channel number has to be entered.
Channel name
If name of the selected device is shown in this column.
Value
In case of a valve switching command, ‘1’ needs to be entered in this field to activate the valve, and with value ‘0’ the valve returns to his standby position. In combination with commands ‘T set’ and ‘FP set’ the new settings are entered here. Commands like ‘autozero’ and ‘start chromatogram’ do not have a value.
Comment
In order to increase the readability of the RTT, comments can be entered for each command line
For a better overview of the RTT, the operator can disable the automatic sort (on retention time) of the table.
On the end of this page, the number of runs is entered. This number will be executed after the start-button is pressed. A number of 999 is equal to infinite analysis.
21
The Run Time Table will automatically sort on retention time. A line can be modified after it has been scrolled to the editing window. Lines can also be added or deleted. Like other parameters, the edited RTT will become active after it has been send to the CompactGC by using the SEND button in the main window .
PULL DOWN MENU’s
File
Besides the functions of the above mentioned command buttons, the CompactGC method can be printed from here.
View
Status
This line has the same function as the Show Status command button.
Log file
From this line, two types op log files, CompactGC -memo, and CompactGC ­actual date can be l oaded to view every normal action and fault messages.
Drawing
This is a viewer for BMP and JPG files, and is used to view the schematic diagram that is supplied with the instrument for convenient editing of the CompactGC (see figure 5.3).
Figure 5.3: View drawing
22
Method
T, F and P defaults Valve and bits default Run time table
These windows offer the same functionality as the TAB pages.
Detector defaults
Figure 5.4: Detector defaults
In addition to the detector settings on the TAB pages, parameters less frequently used are available on this page:
T filament (TCD)
This parameter sets the filament temperature of the TCD. A high value in relation to the TCD block temperature means high sensitivity.
Input gain (TCD)
Gain factor of the input amplifier. A higher value corresponds to higher sensitivity (but noise is more amplified too).
Input polarity (TCD)
Polarity of the TCD signal, depends on the type of carrier gas.
Input current (FID, PDD and PID)
Input range of the detector amplifier. A lower value means higher sensitivity.
23
Sample rate
The number of samples per second (sps) is entered here. The correct value depends on the peak width. F.i. for 0.32 mm id columns, peak widths of 0.5 to 2 seconds are normal. For a correct analog to digital conversion without losing data integrity, 15 to 25 points per peak are necessary. This means a sps value of 25 or 50. In case of analog output, only on this page the sps parameter can be selected. In combination with EZChrom
®
, this setting is overruled by the entered value in the data system, but the choice is limited to the listed values (12.5, 25, 50 and 100 Hz).
High voltage (FID, PDD and PID)
In case of ionization detectors, this parameter switches the polarization voltage on and off.
FID ignite (FID)
After setting the correct detector gas values for hydrogen and air, this button activates the ignition coil in the detector housing for 6 seconds so the flame will turn on. During this time, the hydrogen pressure is raised for better ignition.
Pulser (PDD)
When using the Pulsed Discharge Detector, this buttons start the discharge current.
Lamp (PID)
By this button, the lamp in case of PID is turned on.
Detector analog output
When the analog output is used, the output gain and shift (offset) are enter ed here.
Test chromatogram
After activating this option, during the next run only a synthesized chromatogram is added to the present detector signal. This feature is used for test purposes.
Setup
Comport
For RS 232 communication com1 to com12 can be used.
24
FP calculator
On this page, the column flow can be calculated. The column flow is related to the carrier gas inlet pressure and gas type, the column dimensions and the column temperature. Note that P
(column outlet
out
pressure) also influences this flow; in case of FID and PDD, this pressure is atmospheric, but in case of TCD, this pressure is higher since a restriction tubing is presence between the column end and the TCD. The pressure can be det ermined by measuring the column flow on the detector outlet, and entering the right P
out
value in the calculator. The calculator uses temperature driven viscosity polynominals.
Tmax
This page allows you to protect columns from temperatures above the maximum allowable temperature. The User Tmax can be set, the System Tmax is a fixed value. This parameter is protected by a password. After changing parameters, use the command ‘Send changes to GC’ to save the changes in the CompactGC.
Edit positions.
This option is password protected, and gives the opportunity to change the position of the different devices (temperature and flow/pressure) and detector settings on the TAB pages. Position 100, 200, 300 and 400 are referring to the Front, Middle, Back and Aux channel page. On each page, the following 20 positions are available:
X00 X01 X02 X03 X04 X05 X06 X07 X08 X09 X10 X11 X12 X13 X14 X15 X16 X17 X18 X19
(X = TAB page number) After changing parameters, use the command ‘Send changes to GC’ to save the
changes in the CompactGC.
Edit T/F device names.
This option is password protected, and gives the opportunity to change the names of the temperature controls (f.i. for column name display) and flow devices (f.i. when another carrier gas is used). After changing parameters, use the command ‘Send changes to GC’ to save the changes in the CompactGC.
25
Edit Flame-Off level.
Figure 5.5: Flame-Off window
For safety reason, the FID signal level is monitored after each run; this level is displayed in the STATUS page (only in stand-by mode). In case of a Flame-Off situation, this option avoids spreading of hydrogen in the CompactGC. In the example the ‘action level’ is set to 1 pA; if the signal level drops below this value, the system will:
- go in ‘Hibernate mode’. This means that all gas supply channels will close, and the system will cool down, or
- close the hydrogen channel for that detector only, or
- take no action (so there is NO protection!) The flame on/off status, according to the ‘FID action level’ is also displayed in the
STATUS window.
IMPORTANT: for safety reasons, these parameters need to be set correctly. Especially in case of low-bleed columns, there is a small (1-2 pA) signal drop when the flame goes out, so the ‘FID action level’ needs to be set precisely. It is the responsibility of the end user to obtain an adequate protection level in using these parameters.
When a Flame-Off situation occurs, a warning message (pop-up window in the CGC editor) is displayed, and the operator has 2 minutes time to change the situation before the selected action is executed. When the FID flame is restored, the pop-up window automatically disappears.
The flame-off detection is not active during data acquisition, so make sure there is some spare time between each run (data collection) to detect a possible Flame­Off condition. This time is reserved by setting the ‘start chromatogram’ in the Run Time Table to 1 second or later.
26
Control
Start / Stop analysis:
Function similar to the buttons displayed on the main menu.
FID Flame-Off disable until (re)arming
This command disables the Flame- Off detection when this is temporar y not wanted. The detection is armed again by (1) the following command, (2) a new flame ignition, (3) a CGC restart. The status of the Flame-Off detection (enabled/disabled) is list ed in the STATUS window.
FID Flame-Off arm
This command enables the Flame-Off detection manually. The status of the Flame­Off detection (enabled/disabled) is listed in the STATUS window.
Restart CGC – warm (re)boot
This command allows a remote (soft) restart of the CGC. This menu addition is primary targeted to rest art the system after a Flame-Off alarm that brings the GC in protected mode and/or canceling a Hibernate mode. Note: This warm reset is nearly the same as a mains power on/off, with the exception that a major protective alarm (f.i. in case of a temperature sensor failure) cannot (and should not) be resetted.
About
Displays the software version of this editor program
27
6. Operation
6.1 Column installation
Columns with different external diameter can be installed. See the accessories catalogue for the available dimensions. Normally 0.32 mm id (0.45 mm od, 0.5 mm ferrule needed) columns are used, but also 0.25 mm id and 0.53 mm id (metal) can be applied.
Figure 6.1: Injector (valve) side
Injector (valve) side
• Install the knurled nut and the ferrule (with appropriate internal diameter) without
the column).
• Cut the column end to the correct length, in such a way that no stress is present
on the column after installation.
• Install the column, using the heated aluminum interface path between the
column oven and the valve oven. If the column does not enter the knurled nut on the valve easily, guide it with tweezers or another tool.
• Tighten the nut by hand.
28
Detector side (TCD and FID)
• Install the knurled nut and the ferrule (with appropriate internal diameter) without
the column).
• Cut the column end to the correct length, in such a way that no stress is present
on the column after installation.
• Guide the column into the nut.
• Tighten the nut by hand
nut
nut
valve
Figure 6.2: Column installation
Detector side (PDD)
The distance between the column end, and the lower part of the nut is 11.4 cm.
Figure 6.3: Installation of the column with the PPD detector
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6.2 Leak check
A leak check is performed by pressurizing the sealed system with carrier gas. Any leaks are registered by a drop in the pressure reading. The pneumatic diagram, supplied with the system, is a useful tool.
TCD channel
• turn of the bridge temperature
• turn off the reference gas (send value 0)
• seal the end of the channel by a 1/16” cap on the detector outlet
• set the total flow to zero
• set the inlet pressure to 100 kPa, and after the channel is pressured, set the
pressure to zero
• observe the pressure
FID channel
Extreme care should be taken to a leak-tight gas connection since hydrogen is used as FID feeding gas. This feeding gas is mixed with the carrier gas at the end of the column (see figure 6.2; left nut). In case of a leak, hydrogen will enter the column oven.
For a total check of this channel, the FID detector is disconnected, and the flame jet is replaced by a blind jet.
• turn off the hydrogen and air gas supply (send value 0)
• seal the detector base or the end of the column
• set the total flow to zero
• set the inlet pressure to 100 kPa, and after the channel is pressured, set the
pressure to zero
• observe the pressure
An electronic leakchecker may also be used.
PDD channel
For this channel, except the gas from the digital gas controllers, also discharge gas is supplied directly via a restrictor (see the PDD, chapter 3.4).
• turn off the pulser
• set the total carrier flow to zero
• set the inlet pressure to 150 kPa, and after the channel is pressurized, set the
pressure to zero
• close the external gas supply to the CompactGC
• wait until a stable pressure readout is obtained (approximately 150 kPa) , and
observe if this value remains stable
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6.3 Quick start up
In case of digital data communication (EZChrom®), power-on the CompactGC first, followed by the data system to establish the digital connection.
The following steps are important in starting up the analysis:
Remember that the CompactGC control program is an editor, and ‘SEND’ is necessary to activate the entered values
• install the column, and perform a leak check
• set the correct column flow by adjusting the carrier gas pressure (TAB page). This
flow can be measured on the detector outlet, or can be calculated using the FP calculator (remember that P
depends on the used detector)
out
• set the desired column temperatures depending on the application; in constant
pressure mode, the column flow is dependant on the column temperature, so adjustment of the pressure can be necessary
• send the detector parameters (see chapter 5)
• enter the correct values for valve switching and d ata c o llection in the run time
table
For data-acquisition with EZChrom
®
the command ‘start chromatogram’ should be present (at 1 sec). For analog data collection set output bit 7 to 1 at 1 second, and enter value 0 at 2 seconds.
The end of the run has to be programmed in the RRT (figure 6.4) as well in the data system. Since the CompactGC starts his run directly after the preceding one, and the data system needs time to process and save the acquired data, the runtime of the data system always needs to be shorter than the runtime of the CompactGC (5-10 seconds , depending on the speed of the data system and, if present, the network connection). Enter short valve switching periods for injection (f.i valve on (1) at 1 second; valve off (0) at 2 seconds).
Enter also the number of analysis on this page.
• in case of analog data-acquisition, enter the correct acquisition rate on the
‘detector defaults’ page (with digital data, the EZChrom
®
setting will be copied)
• Set up the data system method: enter the correct data-acquisition rate for each
channel, and a runtime that is 5-10 seconds shorter than the CompactGC runtime; in case of EZChrom start the data system (‘waiting for trigger’ is displayed)
®
, only 12.5, 25, 50 and 100 points per seconds are allowed;
• switch on the detector(s); in case of TCD: activate the Autozero function; the
‘SEND’ command is not needed for this function
• If the CompactGC reports ‘ready’, the run can be started
31
Figure 6.4: run time table window
In case the CompactGC was switched off, the data system has to be closed and restarted for re-establishing the digital communication with EZChrom
®
.
32
7. Maintenance and troubleshooting
Full instrument servicing will normally be performed by an Interscience service engineer under the instrument warranty, or, when this has expired, possibly under a Service Contract Program.
Filters
The filters in the split line of the carrier gas normally need no replacement, since their function is to protect the electronic split regulation by a gradually release of the vented components.
Ferrules Ferrules and seals should be replaced when they are too flat or broken to produce a good seal.
Valves Depending on the type and use of Valco on a regular base.
Log file
In case of electronic failure, inspect the log file (CompactGC editor: view log file).
®
valve, the rotor seals need to be replaced
33
Apendix 1: EZChrom® / EZStart® settings
The datacommunication between EZChrom
®
and the CompactGC is based on the
SS420x protocol. The following parameters need to be entered:
Interface configuration
Tools/interface configuration
When the correct RS-232 connection is present, the information shown at ‘serial number’ confirms the communication with the CompactGC. When not connected, or not active, the window below is shown. The connection should be validated before starting another activity.
34
Instrument configuration
The interface connection window can be closed, and the configuration window of the instrument needs to be opened:
Add modules according the CompactGC configuration. Besides one to three detectors, the event configuration should also be selected.
35
Detector configuration
Detector 1 corresponds to the front channel of the CompactGC, detector 2 to the middle channel, and detector 3 to the CompactGC back channel. Appropriate names can be entered here (FID front, TCD back, etc.).
For TCD, the Y-as Multiplier is set to 0.002500, for FID/PDD/PID 0.00100 has to be entered.
Serial port: corresponding to the used RS-232 port. Channel: 1 for front channel; 2 for middle channel; 3 for back channel
36
Event configuration
When the blue arrow is selected, ‘triggered state closed’ needs to be entered.
The Trigger should also be set to the used RS-232 port in other to start the EZChrom data-acquisition by the CompactGC.
Instrument setup
After finishing the configuration, the instrument can be opened. In EZChrom
®
, open Method/Instrument Setup and configure each channel:
®
37
Complete the setup by setting the external trigger as shown below.
38
Apendix 2: Electrical connections
For both RS 232 connections, a 9-pole D-sub standard RS-232 cable is needed.
Digital input
1
915
8
Pin description Input level 1 D-in bit 0 – start CompactGC L=Tue (TTL/OC/relais) 2 D-in bit 1 – stop CompactGC L=Tue (TTL/OC/relais) 3 D-in bit 2 L=Tue (TTL/OC/relais) 4 D-in bit 3 L=Tue (TTL/OC/relais) 5 D-in bit 4 L=Tue (TTL/OC/relais) 6 D-in bit 5 L=Tue (TTL/OC/relais) 7 D-in bit 6 L=Tue (TTL/OC/relais) 8 D-in bit 7 L=Tue (TTL/OC/relais) 9 ground 0 V 10 ground 0 V 11 ground 0 V 12 ground 0 V 13 ground 0 V 14 ground 0 V 15 ground 0 V
Digital output
(internal pull-up; bit 0-5=10K; bit 6-7=1K )
8
15
1
9
39
Pin Description Output level 1 D-out bit 7 – start out Low active ; open 2 D-out bit 6 – ready Low active ; open 3 D-out bit 5 Low active ; open 4 D-out bit 4 Low active ; open 5 D-out bit 3 Low active ; open 6 D-out bit 2 Low active ; open 7 D-out bit 1 Low active ; open 8 D-out bit 0 Low active ; open 9 Ground 0 V 10 Ground 0 V 11 Ground 0 V 12 Ground 0 V 13 Ground 0 V 14 Ground 0 V 15 Ground 0 V
Analog detector output (optional)
If present, the analog detector is a 9-pole D-sub connector (female on rear CompactGC). This output provides a high stable, high resolution (20 bits) analog signal. In order to preserve the quality as good as possible, short cables are advised. Beside the output signal, two additional connections are important: shield and ground. The shield is not connected at the CompactGC side, and is necessary to protect the signal from external influences. This cable needs to be connected at the data system. The ground connection is necessary to equal the ground level of the CompactGC to the data system, and is important for safety reasons, and omitting damage to the system.
pin Description
1 0 V - front channel 6 1 V - front channel 2 0 V - middle channel 7 1 V - middle channel 3 0 V - back channel 8 1 V - back channel Shield (not connected on CompactGC side;
connect on data system side)
5 ground
40
Apendix 3: LED status display
Green and Red system LED‘s (CompactGC front)
display functionality
GREEN slow blinking (short Off) READY (all active devices) Green Blinking (1 Hz) NOT READY RED off NO RUN RED continuous on RUN (run time table) RED fast blinking (2.5 Hz) ALARM (check log file.)
41
x
IInnddeex
About (Pull down menu’s) 27 Analog detector output
Electrical connections 40 Analog output (Pull down menu’s) 24 Atmosphere 2 Autozero (Run time table) 20 Aux (Tab pages) 19
Back channel (Tab pages) 19 Bits default (Pull down menu’s) 23
Channel (Run time table) 21 Channel name (Run time table) 21 Classification, instrument 4 Column installation 28 Column oven 10 Command (Run time table) 20 Command buttons 18
Get method 18
Send method 18
Start - stop run 19
Status 18 Comment (Run time table) 21 Comport (Pull down menu’s) 24, 27 Control (Pull down menu’s) 27
Demand 5 Detector analog output (Pull down
menu’s) 24 Detector configuration 36 Detector defaults (Pull down menu’s) 23 Detectors 11 Digital connections 5 Digital input 5
Electrical connections 39 Digital output 5
Electrical connections 39 Drawing (Pull down menu’s) 22
Edit positions (Pull d own menu’s) 25, 26 Editor program 17 Electrical connections 39 End of this run (Run time table) 21 Entry (Run time table) 19
Event configuration 37 EZChrom® / EZStart® connections 5 EZChrom® / EZStart® settings 34
Ferrules 33 FID 12
High voltage (Pull down menu’s) 24 Ignite (Pull down menu’s) 24 Input current (Pull down menu’s) 23
Leak check 30 File (Pull down menu’s) 22 Filters 33 FP set (Run time table) 20 FPM
Digital gas supply 8 Front channel (Tab pages) 19
Gas supply 8 Gasses 4
Connections 4
Demand 5
Pressure 4
Quality 4 Get Method (Command button) 18 Ground 2
High voltage (Pull down menu’s) 24 Hydrogen, use of 3
Ignite (Pull down menu’s) 24 Input current (Pull down menu’s) 23 Input gain (Pull down menu’s) 23 Input polarity (Pull down menu’s) 23 Installation 4 Instrument configuration 35 Instrument description 7 Instrument setup 37 Interface configuration 34
Lamp (Pull down menu’s) 24 Leak check 30 LED status display 41 Load default method (Run time table) 21 Lock (Run time table) 19
Log file 33 Log file (Pull down menu’s) 22
Maintenance 33 Method (Pull down menu’s) 23 Middle channel (Tab pages) 19 Operation 28 Output bit (Run time table) 20 Oven
Column 10 Valve 10
PDD 14
High voltage (Pull down menu’s) 24 Input current (Pull down menu’s) 23 Leak check 30 Pulser (Pull down menu’s) 24
PID 15
High voltage (Pull down menu’s) 24 Input current (Pull down menu’s) 23
Lamp (Pull down menu’s) 24 Power requirements 5 Pre-concentration Module 16 Pull down menu’s 22 Pulser (Pull down menu’s) 24
Quick start up 31 Reset sequence counter (Run time
table) 21 RTT (Tab pages) 19 Run time table (Pull down menu’s) 23 Run time table (Tab pages) 19
Safety 2 Sample rate (Pull down menu’s) 24 Send method (Command button) 18 Sequence (Run time table) 20
Setup (Pull down menu’s) 24 Software 17 Space requirements 4 Start chromatogram (Run time table) 20 Start run (Command buttons) 19 STATUS (Command button) 18 Status (Pull down menu’s) 22 Stop run (Command button) 19
T filament (Pull down menu’s) 23 T set (Run time table) 20 T, F and P defaults (Pull down menu’s) 23 Tab pages 19
Aux 19 Front - middle - back channel 19 Run time table 19 Valves 19
TCD 11
Input gain (Pull down menu’s) 23 Input polarity (Pull down menu’s) 23 Leak check 30 T filament (Pull down menu’s) 23
Test chromatogram (Pull down menu’s)
24 Time (Run time table) 19 Tmax (Pull down menu’s) 25 Tools/interface configuration 34 Troubleshooting 33
Value (Run time table) 21 Valve (Run time table) 20 Valve default (Pull down menu’s) 23 Valve oven 10 Valves
Maintenance and troubleshooting 33 Valves (Tab pages) 19 Ventilation 4 View (Pull down menu’s) 22
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