Configure Operation

Trigger Tab

The Trigger tab for the Configure operation contains the following options:

• Type —The event that triggers the oscilloscope.

  Supported Value	Description
  AC Line (7)	Configures the oscilloscope for AC Line triggering.
  Edge (1)	Configures the oscilloscope for edge triggering. An edge trigger occurs when the trigger signal specified with the Trigger Source setting passes the voltage threshold specified with the Trigger Level setting and has the slope specified with the Trigger Slope setting.
  Glitch (4)	Configures the oscilloscope for glitch triggering.
  Immediate (6)	Configures the oscilloscope for immediate triggering. The oscilloscope does not wait for a trigger of any kind upon initialization.
  Runt (3)	Configures the oscilloscope for runt triggering.
  TV (5)	Configures the oscilloscope for triggering on TV signals.
  Width (2)	Configures the oscilloscope for width triggering.

• Source —The source the oscilloscope monitors for the trigger event. Source is a string that can be a defined virtual channel name, an instrument specific channel string, or one of the following defined values:

  "IVISCOPE_VAL_EXTERNAL"	"IVISCOPE_VAL_TTL5"	"IVISCOPE_VAL_RTSI_1"
  "IVISCOPE_VAL_GPIB_GET"	"IVISCOPE_VAL_TTL6"	"IVISCOPE_VAL_RTSI_2"
  "IVISCOPE_VAL_TTL0"	"IVISCOPE_VAL_TTL7"	"IVISCOPE_VAL_RTSI_3"
  "IVISCOPE_VAL_TTL1"	"IVISCOPE_VAL_ECL0"	"IVISCOPE_VAL_RTSI_4"
  "IVISCOPE_VAL_TTL2"	"IVISCOPE_VAL_ECL1"	"IVISCOPE_VAL_RTSI_5"
  "IVISCOPE_VAL_TTL3"	"IVISCOPE_VAL_PXI_STAR"	"IVISCOPE_VAL_RTSI_6"
  "IVISCOPE_VAL_TTL4"	"IVISCOPE_VAL_RTSI_0"

• Holdoff —The length of time, in seconds, the oscilloscope waits between detecting a trigger and enabling the trigger subsystem to detect another trigger. The Holdoff setting only affects instrument operation when the oscilloscope requires multiple acquisitions to build a complete waveform, such as when the oscilloscope uses equivalent time sampling or when the Acquisition Type is set to Envelope or Average. Many scopes have a small, nonzero value as the minimum value for this setting. To configure the instrument to use the shortest trigger holdoff, specify a value of 0 . The instrument driver coerces any value between 0 and the minimum value you specify to the minimum supported value.
• Coupling —Specifies how the oscilloscope couples the trigger source.

  Supported Value	Description
  AC (0)	Specifies that the oscilloscope AC couples the trigger signal.
  DC (1)	Specifies that the oscilloscope DC couples the trigger signal.
  HF Reject (3)	Specifies that the oscilloscope filters out the high frequencies from the trigger signal.
  LF Reject (4)	Specifies that the oscilloscope filters out the low frequencies from the trigger signal.
  Noise Reject (5)	Specifies that the oscilloscope filters out the noise from the trigger signal.

• Modifier —Determines the behavior of the oscilloscope in the absence of the configured trigger. The value of this setting only affects instrument behavior when the Trigger Modifier extension is enabled.

  Supported Value	Description
  Auto (2)	Specifies that the oscilloscope automatically triggers if the configured trigger does not occur within the timeout period.
  Auto Level (3)	Specifies that the oscilloscope adjusts the trigger level if the trigger you specify does not occur.
  No Trigger Mod (1)	Specifies that the oscilloscope waits until the specified trigger occurs.

• Initiate Continuous —Continuously initiates waveform acquisition when set to True . The value of this setting only affects instrument behavior when the Continuous Acquisition extension is enabled. This setting does not affect the behavior of the Read and Fetch operations because these operations are instrument specific. Set this setting to True when you need continuous updates of the oscilloscope display.
• Level —A level setting for the following trigger types:
  • Edge —The threshold, in volts, for the trigger subsystem. The value of this setting only affects instrument behavior when the Trigger Type setting is set to Edge.
  • Glitch —The threshold, in volts, for the trigger subsystem. The value of this setting only affects instrument behavior when the Glitch Trigger extension and the Trigger Type setting are set to Glitch.
  • Width —The level, in volts, at which the pulse causes a trigger. The value of this setting only affects instrument behavior when the Width Trigger extension and the Trigger Type setting are set to Width.
• Condition —Specifies the condition for the following trigger types:
  • Glitch —The range in which the glitch trigger occurs. This setting determines whether the glitch trigger happens when the oscilloscope detects a pulse with a width less than or greater than the width value. The value of this setting only affects instrument behavior when the Glitch Trigger extension and the Trigger Type setting is set to Glitch.

    Supported Value	Description
    Greater Than (2)	Triggers the oscilloscope when the pulse width is greater than the value you specify with the Glitch Width setting.
    Less Than (1)	Triggers the oscilloscope when the pulse width is less than the value you specify with the Glitch Width setting.

  • Width —Specifies whether a pulse inside or outside the high and low thresholds triggers the oscilloscope. The value of this setting only affects instrument behavior when the Width Trigger extension and the Trigger Type setting are set to Width.

    Supported Value	Description
    Width Outside (2)	Configures the oscilloscope to trigger on pulses that have a width greater than the high threshold or less than the low threshold. You can specify the high and low thresholds with the High Threshold and Low Threshold settings.
    Width Within (1)	Configures the oscilloscope to trigger on pulses that have a width less than the high threshold and greater than the low threshold. You can specify the high and low thresholds with the High Threshold and Low Threshold settings.

• Event —The event on which the oscilloscope triggers. The value of this setting only affects instrument behavior when the TV Trigger extension and the Trigger Type setting are set to TV.

  Supported Value	Description
  Any Field (3)	Sets the oscilloscope to trigger on any field.
  Any Line (4)	Sets the oscilloscope to trigger on any line.
  Field1 (1)	Sets the oscilloscope to trigger on field 1 of the video signal.
  Field2 (2)	Sets the oscilloscope to trigger on field 2 of the video signal.
  Line Number (5)	Sets the oscilloscope to trigger on any line.

• Line Number —The line on which the oscilloscope triggers. The line number setting is independent of the field. To trigger on the first line of the second field, you must configure the line number to the value of 263 (if you presume that the first field has 262 lines). The value of this setting only affects instrument behavior when the TV Trigger extension, the Trigger Type setting is set to TV, and the TV Event setting is set to TV Line Number.
• Signal Format —The format of TV signal on which the oscilloscope triggers. The value of this setting only affects instrument behavior when the TV Trigger extension and the Trigger Type setting are set to TV.

  Supported Value	Description
  NTSC (1)	Configures the oscilloscope to trigger on the NTSC signal format.
  PAL (2)	Configures the oscilloscope to trigger on the PAL signal format.
  SECAM (3)	Configures the oscilloscope to trigger on the SECAM signal format.

• Polarity —Specifies the Polarity setting for the following trigger types:
  • Glitch —The polarity of the glitch. The value of this setting only affects instrument behavior when the Glitch Trigger extension and the Trigger Type setting are set to Glitch.

    Supported Value	Description
    Positive (1)	Triggers the oscilloscope on a positive glitch.
    Negative (2)	Triggers the oscilloscope on a negative glitch.
    Either (3)	Triggers the oscilloscope on either a positive or negative glitch.

  • Runt —The polarity of the runt that triggers the oscilloscope. The value of this setting only affects instrument behavior when the Runt Trigger extension and the Trigger Type setting are set to Runt.

    Supported Value	Description
    Positive (1)	Triggers the oscilloscope on a positive runt. A positive runt occurs when a rising edge crosses the low runt threshold and does not cross the high runt threshold before recrossing the low runt threshold.
    Negative (2)	Triggers the oscilloscope on a negative runt. A negative runt occurs when a falling edge crosses the high runt threshold and does not cross the low runt threshold before recrossing the high runt threshold.
    Either (3)	Triggers the oscilloscope on either a positive or negative runt.

  • TV —The polarity of the TV signal. The value of this setting only affects instrument behavior when the TV Trigger extension and the Trigger Type setting are set to TV.

    Supported Value	Description
    Negative (0)	Configures the oscilloscope to trigger on a negative video sync pulse.
    Positive (1)	Configures the oscilloscope to trigger on a positive video sync pulse.

  • Width —The polarity of the pulse that triggers the oscilloscope. The value of this setting only affects instrument behavior when the Width Trigger extension and Trigger Type is Width.

    Supported Value	Description
    Negative (2)	Configures the oscilloscope to trigger on negative pulses that have a width that meets the condition specified with the Condition setting.
    Positive (1)	Configures the oscilloscope to trigger on positive pulses that have a width that meets the condition specified with the Condition setting.

• Slope —A Slope setting for the following trigger types.
  • AC Line —The slope of the zero crossing upon which the oscilloscope triggers. The value of this setting only affects instrument behavior when the AC Line Trigger extension and the Trigger Type setting are set to AC Line.

    Supported Value	Description
    Positive (1)	Configures the oscilloscope to trigger on positive slope zero crossings of the network supply voltage.
    Negative (2)	Configures the oscilloscope to trigger on negative slope zero crossings of the network supply voltage.
    Either (3)	Configures the oscilloscope to trigger on either positive or negative slope zero crossings of the network supply voltage.

  • Edge —Specifies whether a rising or falling edge triggers the oscilloscope. The value of this setting only affects instrument behavior when the Trigger Type is Edge.

    Supported Value	Description
    Negative (0)	Specifies that a negative (falling) edge passing through the trigger level triggers the oscilloscope.
    Positive (1)	Specifies that a positive (rising) edge passing through the trigger level triggers the oscilloscope.

• Width —Specifies the width setting for the following trigger type:
  • Glitch —The glitch width, in seconds. The oscilloscope triggers when it detects a pulse with a width less than or greater than this value, depending on the value of the Glitch Condition setting. The value of this setting only affects instrument behavior when the Glitch Trigger extension and the Trigger Type setting are set to Glitch.
• High Threshold —The high threshold for the following trigger types:
  • Runt —The high threshold, in volts, the oscilloscope uses for runt triggering. The value of this setting only affects instrument behavior when the Runt Trigger extension and the Trigger Type setting are set to Runt.
  • Width —The high width threshold time, in seconds. For the instrument to trigger, the pulse length must be between the High Threshold and Low Threshold values. The value of this setting only affects instrument behavior when the Width Trigger extension and the Trigger Type setting are set to Width.
• Low Threshold —The high threshold for the following trigger types:
  • Runt —The low threshold, in volts, the oscilloscope uses for runt triggering. The value of this setting only affects instrument behavior when the Runt Trigger extension and the Trigger Type setting are set to Runt.
  • Width —The low width threshold time, in seconds. For the instrument to trigger, the pulse length must be between the High Threshold and Low Threshold values. The value of this setting only affects instrument behavior when the Width Trigger extension and the Trigger Type setting are set to Width.