Agilent 7890A GC

Quick Reference


Keypad and Status Board

Keypad for the 7890A GC 10

The Run Keys 11

The Info Key 12

The Status Key 13

The GC Component Keys 14

The General Data Entry Keys 16

The Supporting Keys 18

Method Storage and Automation Keys 20

The Service Mode Key 22

Keypad Functionality When the GC Is

Controlled by an Agilent Data

System 23

About GC Status 24

Alert tones 26

Blinking setpoint 26

About Logs 27

Agilent Technologies 9

Keypad for the 7890A GC

The next several pages provide an overview of the

Agilent 7890A GC keypad functions. See the Agilent

7890A GC Advanced User Guide along with the complete suite of documentation included on the

Agilent GC and GC/MS Hardware User Information &

Utilities DVD that shipped with your instrument for more detailed information.

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The Run Keys


Immediately terminates the run. If the GC is in the middle of a run, the data from that run may be lost.

Refer to the Agilent 7890A GC Advanced User

Guide for information on how to restart the GC after pressing [Stop].

[Prep Run]

Activates processes required to bring the GC to the starting condition dictated by the method (such as turning off the inlet purge flow for a splitless injection or restoring normal flow from gas saver mode).

[Start] Starts a run after manually injecting a sample.

(When you are using an automatic liquid sampler or gas sampling valve, the run is automatically activated at the appropriate time.)

Quick Reference 11

The Info Key

For context-sensitive help, press [Info]. For example, if you press [Info] on a setpoint entry, the help provided would be similar to: Enter a value between 0 and 350.

[Info] Provides context-sensitive help for the currently shown parameter. For example, if Oven Temp is the active line in the display (has a < next to it),

[Info] will display the valid range of oven temperatures. In other cases, [Info] will display definitions or actions that need to be performed.

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The Status Key

[Status] Toggles between setpoint/actual values for most commonly reviewed parameters and displays

“ready,” “not ready,” and “fault” information.

When the Not Ready status light is blinking, a fault has occurred. Press [Status] to see which parameters are not ready and what fault has occurred.

Quick Reference 13

The GC Component Keys

These keys are used to set the temperature, pressure, flow, velocity, and other method operating parameters.

To display the current settings, press any one of these keys. More than three lines of information may be available. Use the scroll keys to view additional lines, if necessary.

To change settings, scroll to the line of interest, enter the change, and press [Enter].

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[Oven] Sets oven temperatures, both isothermal and temperature programmed.

Controls inlet operating parameters.

[Front Inlet]

[Back Inlet]

[Col 1]

[Col 2]

[Aux Col #]

[Front Det]

[Back Det]

[Aux Det #]

[Analog Out 1]

[Analog Out 2]

Controls column pressure, flow, or velocity.

Can set pressure or flow ramps.

Controls detector operating parameters.

[Front Injector]

[Back Injector]

[Valve #]

[Aux Temp #]

[Aux EPC #]

Assigns a signal to the analog output. The analog output is located on the back of the


Edits injector control parameters such as injection volumes and sample and solvent washes.

Allows for configuration or control of the gas sampling valve (GSV) and/or switching valves

1 to 8 on or off. Sets multiposition valve position.

Controls extra temperature zones such as a heated valve box, a mass selective detector, an atomic emission detector transfer line, or an “unknown” device. Can be used for temperature programming.

Provides auxiliary pneumatics to an inlet, detector, or other device. Can be used for pressure programming.

[Column Comp] Creates a column compensation profile.

Quick Reference 15

The General Data Entry Keys

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Accesses a list of possible parameters associated with a component’s nonnumeric settings. For example, if the GC is configured with a split/splitless inlet and the [Mode/Type] key is pressed, the options listed will be split, splitless, pulsed split, or pulsed splitless.

Removes a misentered setpoint before pressing

[Enter]. It can also be used to return to the top line of a multiline display, return to a previous display, cancel a function during a sequence or method, or cancel loading or storing sequences and methods.

Accepts changes you enter or selects an alternate mode.

Scrolls up and down through the display one line at a time. The < in the display indicates the active line.

Enters settings for the method parameters (Press

[Enter] when you are finished to accept the changes.)

Sets parameters, such as the warning beep, method modification beep, and key click or for turning on or off a device like a detector.

Identifies configuration settings. For example, when configuring a column, use these keys to identify the inlet and detector to which the column is attached.

Removes methods, sequences, run table entries, and clock table entries. [Delete] also aborts the adjust offset process for nitrogen-phosphorus detectors (NPD) without interrupting other detector parameters. See the Agilent 7890A GC

Advanced User Guide for more details.

Quick Reference 17

The Supporting Keys

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[Time] Displays the current date and time on the first line.

The two middle lines show the time between runs, the elapsed time and time remaining during a run, and the last run time and post-time during a post-run.

[Post Run] Programs the GC to do something after a run, such as bakeout or backflush a column. See the Agilent

7890A GC Advanced User Guide for details.

[Logs] Toggles among three logs: the Run Log, the Maintenance Log, and the System Event Log. The information in these logs can be used to support Good

Laboratory Practices (GLP) standards.


The last line always displays a stopwatch. While on the stopwatch line, press [Clear] to set the clock to zero and [Enter] to start or stop the stopwatch.


Accesses the instrument parameters setup option, such as keypad, display, and diagnostics. Scroll to the desired line and press [Enter] to access the associated entries. See the Agilent 7890A GC

Advanced User Guide for details.

Sets up components that are not automatically detectable by the GC but are essential to running a method, such as column dimensions, carrier and detector gas types, makeup gas configurations, sample tray settings, and column plumbing to inlets and detectors. These settings are part of, and are stored with, the method.

To view the current configuration for a component

(such as the inlet or detector), press [Config], then the component key of interest.

Quick Reference 19

Method Storage and Automation Keys

These keys are for loading and storing methods and sequences locally on your GC. They cannot be used to access methods and sequences stored by your Agilent


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Loads and stores methods and sequences on your GC.

[Run Table]

[Clock Table]

[Seq Control]

To load a method, press [Load] [Method] and select one from the list of methods stored in the GC. See the Agilent 7890A GC Advanced

User Guide for more details on these operations.

Programs special events you require during a run. A special event could be switching a valve, for example. See the Agilent 7890A GC

Advanced User Guide for details.

Programs events to occur at a time of day, as opposed to during a specific run. This could, for example, be used to start a shutdown run at

5:00 p.m. every day. See the Agilent 7890A GC

Advanced User Guide for details on this function.

Starts, stops, pauses, or resumes a sequence, or views the status of a sequence. See the

Agilent 7890A GC Advanced User Guide for details.

[Sample Tray] Displays whether the tray and/or bar code reader is enabled.


[User Key 1]

[User Key 2]

Allows you to program a series of keystrokes commonly used for specific operations. See the

Agilent 7890A GC Advanced User Guide .

Quick Reference 21

The Service Mode Key

[Service Mode] Accesses maintenance functions and settings, service counters, and diagnostics for the GC.

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Keypad Functionality When the GC Is Controlled by an Agilent Data System

When an Agilent data system controls the GC, the data system defines the setpoints and runs the samples. If configured to lock the keypad, the data system can prevent the changing of setpoints. The Remote LED is lit when a data system is controlling the GC. Lit LEDs on the status board show the current progress of a run.

When controlled by a data system, the keypad can be used:

To view run status by selecting [Status]

To view the method settings by selecting the GC component key

To display the last and next run times, the run time remaining, and the post-run time remaining by repeatedly selecting [Time]

To abort a run by selecting [Stop]

Quick Reference 23

About GC Status

When the GC is ready to begin a run, the display screen shows STATUS Ready for Injection. Alternatively, when a component of the GC is not ready to begin a run, the

Not Ready LED is lit on the status board. Press [Status] to see a message explaining why the GC is not ready.

Status board

The status board provides a basic look at what is currently happening inside the GC.

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Not Ready



Clock Table

Gas Saver

Run Log

Service Due

Pre Run

Oven Ramp


Final Temp

Post Run

Lights when the GC is not yet ready to process a sample and blinks when a fault occurs.

Press [Status] to see which parameters are not ready or what faults have occurred.

Lights when the instrument is executing a chromatographic run.

Lights when the GC is communicating with a remote device (such as the Agilent ChemStation running on a PC). When lit, some functions are blocked from the keypad because they are being controlled by the remote device.

Lights when a clock table event has been set.

See “Method Storage and Automation Keys” on page 20 for more details on Clock Table


Lights when the front or back gas saver is on.

Lights when a run log has entries. Press

[Logs] to view these entries. This information can be used for Good Laboratory Practice

(GLP) standards.

Lights when a service counter has reached the limit you specified.

Lights when the GC is in the pre-run state

(after [Prep Run] is pressed). Indicates that the inlet has been prepared for injection.

Lights indicate the progress of the oven temperature program.

blinks if the oven is unable to follow the oven temperature program.

is lit when the GC reaches the temperature specified in the method.

Lights when the instrument is executing a post-run operation (e.g., printing a report).

Quick Reference 25

Alert tones

A series of warning beeps sounds before a shutdown occurs. After a short time the component with the problem shuts down, the GC emits one beep, and a brief, numbered message is displayed. For example, a series of beeps sounds if the front inlet gas flow cannot reach setpoint. The message Front inlet flow shutdown is briefly displayed. The flow shuts down after 2 minutes. Press [Clear] to stop the beep.

A continuous tone sounds if a hydrogen flow is shut down or a thermal shutdown occurs.


Before resuming GC operations, investigate and resolve the cause of the hydrogen shutdown. See Hydrogen

Shutdown in the Troubleshooting manual for details.

One beep sounds when a problem exists, but the problem will not prevent the GC from executing the run.

The GC will emit one beep and display a message. The

GC can start the run and the warning will disappear when a run starts.

Fault messages indicate hardware problems that require user intervention. Depending on the type of error, the GC emits no beep or a single beep.

Blinking setpoint

If a gas flow, multiposition valve, or the oven is shut down by the system, Off will blink on the appropriate line of the component’s parameter listing.

If there is a pneumatics shutdown or failure in another part of the detector, the detector On/Off line of the detector’s parameter list blinks.

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About Logs

Three logs are accessible from the keypad: the run log, the maintenance log, and the system event log. To access the logs, press [Logs] and toggle to the desired log. The display will indicate the number of entries the log contains. Scroll through the list.

Run log

The run log is cleared at the start of each new run.

During the current run, any deviations from the planned method (including keypad entries) are listed in the run log table. When the run log contains entries, the Run

Log LED lights.

Maintenance log

The maintenance log contains entries made by the system when any of the user-defined component counters reach a monitored limit. The log entry contains a description of the counter, its current value, the monitored limits, and which of its limits has been reached. In addition, each user task related to the counter is recorded in the log, including resetting, enabling or disabling monitoring, and changing limits or units (cycles or duration).

System event log

The system event log records significant events during the GC’s operation. Some of the events also appear in the run log if they are in effect during a run.

Quick Reference 27

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