Agilent Technologies 7820A Assembly instructions

Agilent Technologies
Agilent 7820A
Gas Chromatograph
Advanced User Guide

Notices
Agilent Technologies, Inc. 2016
No part of this manual may be reproduced
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tion into a foreign language) without prior
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Agilent Technologies, Inc. as governed by
United States and international copyright
laws.
Manual Part Number
G4350-90020
Edition
Fifth edition, August 2016
Fourth edition, September 2015
Third edition, June 2011
Second edition, January 2010
First edition, March 2009
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The hardware and/or software described in
this document are furnished under a
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accordance with the terms of such license.
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(June 1995), or as a “commercial item” as
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Safety Notices
CAUTION
A CAUTION notice denotes a hazard. It
calls attention to an operating
procedure, practice, or the like that, if
not correctly performed or adhered to,
could result in damage to the product
or loss of important data. Do not
proceed beyond a CAUTION notice
until the indicated conditions are fully
understood and met.
WARNING
A WARNING notice denotes a hazard.
It calls attention to an operating
procedure, practice, or the like that, if
not correctly performed or adhered to,
could result in personal injury or
death. Do not proceed beyond a
WARNING notice until the indicated
conditions are fully understood and
met.
Firmware Version
This manual is written for 7820A GCs using
firmware version A.01.18.

Advanced User Guide 3
Contents
1 Software Keypad
Using the Software Keypad 10
2 Programming
Run Time Programming 12
Using run time events 12
Programming run time events 13
The run table 13
Adding events to the run table 13
Editing events in the run table 14
Deleting run time events 14
Clock Time Programming 15
Using clock time events 15
Programming clock time events 15
Adding events to the clock table 15
Editing clock time events 16
Deleting clock time events 16
Post Run Programming 17
To enable a post run program 17
To disable a post run program 17
3 Inlets
Using Hydrogen 20
Inlet Overview 21
Carrier Gas Flow Rates 22
About Gas Saver 23
To use gas saver 24
Pre Run and Prep Run 25
The [Prep Run] key 25
Auto Prep Run 26
About the Split/Splitless Inlet 27
Septum tightening (S/SL) 27
Standard S/SL inlet 28
Split/Splitless inlet split mode overview 28
Split/Splitless inlet splitless mode overview 29
The S/SL inlet pulsed split and splitless modes 30
Split/Splitless inlet split mode minimum operating pressures 31

4 Advanced User Guide
Selecting the correct S/SL inlet liner 32
Vapor Volume Calculator 34
Setting parameters for the S/SL split mode 34
Selecting parameters for the S/SL splitless mode 36
Setting parameters for the S/SL splitless mode 36
Setting parameters for the S/SL pulsed modes 38
About the Purged Packed Column Inlet 39
Setting parameters 40
About the Packed Column Inlet 41
Adjusting parameters 42
About the Cool On-Column Inlet 43
Setup modes of the COC inlet 44
Retention gaps 44
COC inlet temperature control 44
Setting COC inlet flows/pressures 45
Setting COC inlet parameters 46
4 Columns and Oven
About the Oven 48
Oven safety 48
Configuring the Oven 49
About Oven Temperature Programming 50
Programming setpoints 50
Oven ramp rates 51
Setting the oven parameters for constant temperature 51
Setting the oven parameters for ramped temperature 52
About Columns 53
Selecting the correct packed glass column type 53
About the column modes 53
Select a column mode 54
Setting the column parameters for constant flow or constant
pressure 55
Enter a flow or pressure program (optional) 55
Programming column pressure or flow 56
Advantages of the optional Backflush Wizard 56
Procedures for manually creating a backflush method 57
Nickel Catalyst Tube 61
About the nickel catalyst tube 61
Nickel catalyst gas flows 61
Setting temperatures for the nickel catalyst tube 62

Advanced User Guide 5
Hydrogen Sensor 63
Instrument logs 63
Calibration 63
Status information 63
Operation with an Agilent data system 64
5 Detectors
About Makeup Gas 66
About the FID 67
How FID units are displayed in Agilent data systems and on the GC 68
To light the FID flame 68
To extinguish the FID flame 68
FID automatic reignition (Lit offset) 68
Recommended starting conditions for new FID methods 69
Setting parameters for FID 70
About the TCD 71
TCD pneumatics 73
TCD carrier, reference, and makeup gas 73
TCD gas pressures 74
Selecting reference and makeup flows for the TCD 75
Chemically active compounds reduce TCD filament life 75
Changing the TCD polarity during a run 76
Detecting hydrogen with the TCD using helium carrier gas 76
Setting parameters for the TCD 76
About the µECD 79
µECD safety and regulatory information 79
µECD warnings 80
µECD gas flows 82
µECD linearity 82
µECD detector gas 82
µECD temperature 83
µECD analog output 83
Recommended starting conditions for new µECD methods 83
µECD makeup gas notes 83
µECD temperature programming 84
Setting parameters for the µECD 84
About the NPD 85
NPD flows and general information 85
NPD flow, temperature, and bead recommendations 86
NPD required gas purity 87
Setting parameters for the NPD 88
Selecting an NPD bead type 89

6 Advanced User Guide
Selecting an NPD jet 90
To configure the NPD 91
Automatically adjusting NPD bead voltage 92
Setting NPD adjust offset on the clock table 93
Aborting NPD adjust offset 93
Extending the NPD bead life 93
Setting the initial bead voltage for new beads 94
Setting NPD bead voltage manually (optional) 94
About the FPD+96
FPD+linearity 97
FPD+Lit Offset 97
FPD+photomultiplier protection 97
FPD+optical filters 98
Inlet liners for use with the FPD+98
FPD+temperature considerations 98
FPD+gas purity 99
FPD+gas flows 99
Lighting the FPD+flame 99
Setting parameters for the FPD+100
About the FPD 102
FPD linearity 103
FPD Lit Offset 103
Starting Up and Shutting Down the FPD 103
FPD photomultiplier protection 103
FPD optical filters 103
Inlet liners for use with the FPD 104
FPD temperature considerations 104
FPD gas purity 104
FPD gas flows 104
Lighting the FPD flame 105
Setting parameters for the FPD 106
6 Valves
The Valve Box 110
Heating the valves 110
Valve temperature programming 110
Valve Control 111
The valve drivers 111
The internal valve drivers 111
Valve Types 113
Configuring a Valve 114

Advanced User Guide 7
Controlling a Valve 115
From the keyboard 115
From the run or clock time tables 115
Gas sampling valve 115
7 GC Output Signals
About Signals 118
Analog Signals 119
Analog zero 119
Analog range 119
Analog data rates 120
Selecting fast peaks (analog output) 121
Digital Signals 122
Digital zero 122
Signal Freeze and Resume 122
Data rates with Agilent data systems 123
Zero Init Data Files 125
8 Auxiliary Devices
About Pressure Control 128
Pressure units 128

8 Advanced User Guide

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Agilent 7820A Gas Chromatograph
Advanced User Guide
Agilent Technologies
1
Software Keypad

10 Advanced User Guide
1Software Keypad
Using the Software Keypad
The Agilent software keypad (remote controller) provides the
ability to program and use the 7820A Gas Chromatograph (GC).
Refer to the Operating Guide for instructions for its installation
and use.
All instructions in this manual assume the use of the software
keypad unless otherwise noted.
Figure 1 Software keypad (remote controller)

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Agilent 7820A Gas Chromatograph
Advanced User Guide
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Agilent Technologies
2
Programming
Run Time Programming 12
Using run time events 12
Programming run time events 13
The run table 13
Adding events to the run table 13
Editing events in the run table 14
Deleting run time events 14
Clock Time Programming 15
Using clock time events 15
Programming clock time events 15
Adding events to the clock table 15
Editing clock time events 16
Deleting clock time events 16
Post Run Programming 17

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Run Time Programming
Run time programming during a method allows certain
setpoints to change automatically during a run as a function of
the chromatographic run time. Thus an event that is
programmed to occur at 2 minutes will occur 2 minutes after
every injection.
Its uses include:
•Controlling column switching or other valves
•Changing analog signal definition, zero, or range
•Controlling an auxiliary pressure channel
•Changing polarity of a thermal conductivity detector (TCD)
•Turning the hydrogen flow to a nitrogen-phosphorus
detector (NPD) on or off
•Switching digital signal output (requires an Agilent data
system)
•Pausing (“freezing”) and resuming digital signal output
(requires an Agilent data system)
The changes are entered into a run table that specifies the
setpoint to be changed, the time for the change, and the new
value. At the end of the chromatographic run, most setpoints
changed by a run time table are returned to their original
values.
Valves can be run time programmed but are not restored to
their starting position at the end of the run. You must program
the reset operation in the run table if this action is desired. See
“From the run or clock time tables” on page 115.
Using run time events
The [Run Table] key is used to program the following timed
events.
•Valves (1-2)
•Analog signal definition, zero, and range
•TCD negative polarity (on/off)
•Detector gas flow (on/off), including NPD H2fuel gas

Programming 2
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Programming run time events
1Press [Run Table].
2Press [Mode/Type] to see the available run time events.
3Scroll to the event to be programmed. Press [Enter].
4Enter values for the Time: and the other parameter. Press
[Enter] after each entry.
5Press [Mode/Type] to add another event. Press [Status] to
terminate entries.
The run table
The programmed events are arranged in order of execution time
in the Run Table. This is a brief example:
RUN TABLE (1 of 3) Event 1 rotates a valve.
Time: 0.10
Valve #2 On
RUN TABLE (2 of 3) Event 2 adjusts the signal
Time: 3 range.
Analog signal 2 range 2
RUN TABLE (3 of 3) Event 3 resets Valve #2 to its
Time: 4.20 original position in preparation
Valve #2 Off for another run. Valves do not
reset automatically.
Adding events to the run table
1To add new events to the run table, press [Mode/Type] while
on the Time: line of any entry.
2Select the event type.
3Set appropriate Time: and other parameters. Some require
numbers; others require [On/Yes] or [Off/No].
4Repeat until all entries are added. Events are automatically
placed in order by execution time.

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Editing events in the run table
1Press [Run Table].
2Move the cursor to the event you want to change.
3To edit the time for an event, move the cursor to the line
labeled Time:. Type the desired time and press [Enter].
4To edit a setpoint value, scroll to the setpoint line. Press
[On/Yes] or [Off/No] or enter a numeric value for the
setpoint. Press [Enter].
Deleting run time events
1Press [Run Table].
2From within this table press [Delete] to delete events from
the run time table. You will be asked to confirm the deletion.
3Press [On/Yes] to delete the current timed event; press
[Off/No] to cancel this operation.
4To delete the entire table, press [Delete][Run Table].

Programming 2
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Clock Time Programming
Clock time programming allows certain setpoints to change
automatically at a specified time during a 24-hour day. Thus, an
event programmed to occur at 14:35 hours will occur at 2:35 in
the afternoon. A running analysis or sequence has precedence
over any clock table events occurring during this time. Such
events are not executed.
Possible clock time events include:
•Valve control
•Method and sequence loading
•Starting sequences
•Initiating blank and prep runs
•Column compensation changes
•Adjustments of the detector offset
Using clock time events
The Clock Table function allows you to program events to occur
during a day based on the 24-hour clock. Clock table events that
would occur during a run or sequence are ignored.
For example, the clock table could be used to make a blank run
before you even get to work in the morning.
Programming clock time events
1Press [Clock Table].
2Press [Mode/Type] to see the available clock time events.
3Scroll to the parameter to be programmed.
4Edit Time: and the setpoints for this event.
5Press [Mode/Type] to add another event. Press [Status] to
terminate entries.
When the clock event is executed, a confirming message
appears.
Adding events to the clock table
1Press [Clock Table].
2Press [Mode/Type]. When entries are added, they are
automatically ordered chronologically.

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3Select the event type.
4Set appropriate parameters.
5Repeat this process until all entries are added.
Editing clock time events
1Press [Clock Table] to view all events programmed.
2Scroll to the event you want to change.
3To edit the time for an event, move the cursor to the line
labelled Time: and type the desired time.
4To edit a setpoint value, scroll to the setpoint item. Press
[On/Yes] or [Off/No], or enter a numerical value for the
setpoint.
Deleting clock time events
1Press [Clock Table].
2Use [Delete] to remove events from the clock time table. You
will be asked to confirm the deletion.
3Press [On/Yes] to delete the current timed event; press
[Off/No] to cancel this operation.
To delete the entire table, press [Delete][Clock Table].

Programming 2
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Post Run Programming
This function can be used with both isothermal and
programmed methods. Post run is a period that begins at the
end of the normal run. The parameters include:
•Time—How long is the post run period?
•Oven Temperature—What is the oven temperature during the
post run period?
•Column npres—For a column controlled in a pressure mode,
enter the pressure for this column during the post run
period.
•Column nflow—For a column controlled in a flow mode, enter
the flow rate for this column during the post run period.
Post run may be used to clean out a column in preparation for
the next run, backflush a column to eliminate high-boilers, and
other functions.
When the Post run Time elapses, the GC returns to the initial
state defined in the current method.
To enable a post run program
1Press [Post Run].
2Type a non-zero time for the post run duration and press
[Enter]. The post run parameters available for the current GC
configuration appear.
3Scroll to each desired parameter, type the value for the post
run period, and press [Enter].
To disable a post run program
1Press [Post Run].
2Type a 0 as the post run time and press [Enter].
NOTE EPR (electronic pneumatics regulation) equipped GCs do not support post
run parameters for Column n pres and Column n flow since column
pressure and flow are set manually.

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Agilent 7820A Gas Chromatograph
Advanced User Guide
Agilent Technologies
3
Inlets
Using Hydrogen 20
Inlet Overview 21
Carrier Gas Flow Rates 22
About Gas Saver 23
Pre Run and Prep Run 25
Auto Prep Run 26
About the Split/Splitless Inlet 27
Split/Splitless inlet split mode overview 28
Split/Splitless inlet splitless mode overview 29
The S/SL inlet pulsed split and splitless modes 30
Split/Splitless inlet split mode minimum operating pressures 31
Selecting the correct S/SL inlet liner 32
Vapor Volume Calculator 34
Selecting parameters for the S/SL splitless mode 36
About the Purged Packed Column Inlet 39
Setting parameters 40
About the Packed Column Inlet 41
Setting parameters 40
About the Cool On-Column Inlet 43
Retention gaps 44
COC inlet temperature control
44
Setting COC inlet flows/pressures 45

20 Advanced User Guide
3Inlets
Using Hydrogen
WARNING When using hydrogen (H2), as the carrier gas, be aware that
hydrogen (H2) gas can flow into the oven and create an explosion
hazard. Therefore, be sure that the supply is off until all
connections are made, and ensure that the inlet and detector
column fittings are either connected to a column or capped at all
times when hydrogen (H2) gas is supplied to the instrument.
WARNING Hydrogen (H2) is flammable. Leaks, when confined in an enclosed
space, may create a fire or explosion hazard. In any application
using hydrogen (H2), leak test all connections, lines, and valves
before operating the instrument. Always turn off the hydrogen
(H2) supply at its source before working on the instrument.