Option

Description

Voltage range

(Available when No Simulation (Off) or Record Simulation File is selected in the Simulation Mode box on the General page.)

Select the required voltage range (input range) for the A2D from the list. The A2D supports voltage ranges of +/-1 V, +/-2 V, +/-5 V and +/-10 V.

 Note: 

If both Channel 1 and Channel 2 pages are available, a different voltage range can be set for each channel on the respective page.

File name

(Available when Record Simulation File or Replay Simulation File is selected in the Simulation Mode box on the General page.)

Enter the name of the simulation file to be recorded or select the file to be replayed from the list.

Availability

Acquired data can be delivered to either a channel or a port. Select the acquisition mode from the list. The following modes are available:

• Timebase A2D Channel: Select this mode (channel acquisition mode) to acquire data using an A2D channel associated with a timebase (specify the timebase in the On timebase box). When this mode is selected, data acquisition is controlled by this channel and data is recorded within this channel. Data acquisition using an ADC port is not supported in this mode.

 Note: 

PGM Files for the timebase reference only channels configured for the timebase. Sequences run independently across timebases sharing channels on a single A2D.

• Shared Analog Port: Select this mode (port acquisition mode) to use an ADC port to acquire data. The ADC port can be used by a channel from a different driver (device on the same or a different timebase). When this mode is selected, data acquisition is controlled by the port using the channel and data is recorded within this port-using channel.

 Note: 

An ADC port can have the following names: A2D_ADC and A2D_ADC2.

• Do not use (Disable): Select this mode to disable the channel or ADC port (and all associated fields in the Channel page). Data acquisition for the channel or ADC port is not possible in this mode.

On timebase

(Available only when Timebase A2D Channel is selected in the Availability list)

From the list, select the timebase with which the A2D channel will be associated.

Synchronization

(Available only when Timebase A2D Channel is selected in the Availability list AND No Simulation (Off) or Record Simulation File is selected in the Simulation Mode box on the General page.)

Use the synchronization options to determine how A2D data acquisition is synchronized with external hardware (such as an autosampler). Each A2D channel provides a dedicated TTL (transistor–transistor logic) digital input, which can be used to synchronize with external devices. A2D data acquisition of an analog signal begins precisely at (or relative to) the time the input signal is provided. This feature applies to both controlled and uncontrolled autosampler configurations.

Select one of the following synchronization options:

• Uncontrolled Autosampler: Typically, the start input is used to synchronize the start of data acquisition with an injection from an autosampler that is not controlled by Chromeleon. Select this option to enable Chromeleon to provide an Inject command, which is used in the PGM File to hold the program until the A2D has received an injected signal from an autosampler connected to the channel’s start input. A2D data acquisition is synchronized with the autosampler start signal, ensuring that data is acquired precisely when the start signal is received. In addition, Chromeleon closes a relay contact when the Inject command is executed, which indicates a Ready state to the autosampler. Relay 1 is used by Channel 1 and Relay 2 is used by Channel 2. Any connected autosampler is not directly controlled by this Inject command, so Chromeleon does not perform any validation of vial positions and injection volumes specified in the sequence.

• Controlled Autosampler: Select this option to synchronize the start of data acquisition with an injection from an autosampler that is controlled by Chromeleon. When this option is selected, A2D data acquisition is synchronized with the autosampler start signal, ensuring that data is acquired precisely when the start signal is received.

• None: When this option is selected, the start input is not monitored and the A2D starts acquiring data when the AcqOn command is executed by the PGM File.

Integrate acquired data

(Available only in channel acquisition mode, i.e. when Timebase A2D Channel is selected in the Availability list.)

Select this check box to enable Chromeleon to automatically integrate the data acquired using the A2D channel. In general, the check box should be selected for the acquisition of chromatography signals (e.g. absorbance data), and it should be cleared for the acquisition of diagnostic signals (e.g. instrument parameter data such as pressure).

 Note: 

In port acquisition mode, the channel using the ADC port controls data integration. Most of the drivers that implement such a channel do not provide this setting because the type of data is known by the driver.

Offset

Use this setting to offset the signal (mV) from the A2D by a positive or negative number of mV, e.g. to compensate for analog signal port irregularities. By default, the offset is 0.000 mV. If required, enter a positive or negative offset value (mV).

Scaling factor

Use this setting to scale the overall A2D signal (before any Offset setting) by a factor, e.g. to correspond to a desired range such as temperature or pressure. By default, the factor is 1.000. If required, enter a different value for the factor.

Units label

Enter a units label for the acquired channel data. For example, you might enter a °C label after entering a scaling factor to scale the signal data from mV to a temperature range. By default the label is mV.