PXIe VNA Help
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External and Auxiliary Triggering

External and auxiliary triggering is used to synchronize the triggering of the analyzer with other equipment.

  1. Overview

  2. How to make Trigger Settings:

See Also

Overview

Ready Signals versus Trigger Signals

A 'Ready for Trigger' signal is different from a Trigger signal. The ready signal indicates that the instrument sending the signal is ready for measurement. The instrument receiving the ready signal would then send a trigger signal, indicating that the measurement will be, or has been, made. Usually the slower instrument sends the trigger signal.

Learn more about each type of triggering signal:

Meas (External) Trigger dialog box help

M980xA, M983xA

P50xxA/B, P93xxB

M937xA

P937xA

 

See how to access the Trigger Dialog

Trigger Ready and Trigger IN

The Trigger connectors are located on the front-panel. M980xA P50xxA/B and P93xxB requires I/O Adapter and a setup for trigger port assignment. Refer to I/O Connector (M9485A) for M9485A.

The Trigger connectors are located on the rear-panel.

These signals can be used when the VNA is communicating with a slow mechanical device. A material handler is very mechanical and takes a relatively long time to load and discharge parts. Here is how these signals work together to communicate:

  1. The VNA sends a 'Ready' signal when it is ready to make a measurement.

  2. The external device sends a trigger signal to the VNA when it is ready for a measurement.

  3. Additional signals are available on the VNA Handler I/O to indicate that the VNA sweep has ended, and that the handler can setup for the next measurement. See Material Handler I/O description.

Dialog Settings

To cause the VNA to respond to Meas Trig IN or Handler I/O signals, select External on the Trigger Setup tab, Source setting.

Note: You must select External when you use any external triggers.

Also on the Trigger Setup tab, Scope setting, choose whether one external trigger signal will apply to ALL channels (Global) or one trigger signal per Channel. The following settings apply accordingly.

Main Trigger Input

Global / Channel Trigger Delay  After an external trigger is received, the start of the sweep is held off for this specified amount of time plus any inherent latency.

  • When Trigger Scope = Channel, the delay value is applied to the specified channel.

  • When Trigger Scope = Global, the same delay value is applied to ALL channels.

Source  The VNA accepts Trigger IN signals through the following connectors:

  • Trig In SMB [Ctrl S] (on front panel of module [M937xA,P937xA], On I/O Adapter [M98xxA,P50xxA/B,P93xxB])

  • Handler I/O Pin 18 (This appears when the M9341A is included at launcher.)

Note: When Handler I/O Pin 18 is selected, the connection between Meas Trig In SMB and M9341A is required. See M9341A Module Installation.

  • Pulse3 (Pulsed option only): Trigger signals are routed internally without the need of a cable connection between the pulse 3 output and the external trigger input.

  • Backplane: (PXI) Assign PXI TRIG n as a trigger input. Trigger line setup in chassis SFP is required. See the chassis SFP manual.

  • Rear SMB: (USB VNAs) This selection is used when you use a trigger port 1 or 2 on rear panel of USB VNA

Level / Edge  

High Level  The VNA is triggered when it is armed (ready for trigger) and the TTL signal at the select input is HIGH.

Low Level  The VNA is triggered when it is armed (ready for trigger) and the TTL signal at the select input is LOW.

Positive Edge  After the VNA arms, it will trigger on the next positive edge. If Accept Trigger Before Armed is set, the VNA will trigger as soon as it arms if a positive edge was received since the last data was taken.

Negative Edge  After the VNA arms, it will trigger on the next negative edge. If Accept Trigger Before Armed is set, the VNA will trigger as soon as it arms if a negative edge was received since the last data was taken.

Accept Trigger Before Armed  When checked, as the VNA becomes armed (ready to be triggered), the VNA will immediately trigger if any triggers were received since the last taking of data. The VNA remembers only one trigger signal. All others are ignored.

  • When this checkbox is cleared, any trigger signal received before VNA is armed is ignored.

  • This feature is only available when positive or negative EDGE triggering is selected.

  • Configure this setting remotely using CONTrol:SIGNal (SCPI) .

Ready for Trigger Indicator (Trigger Ready)

On the VNA, when External is selected on the Trigger Setup tab, then both Meas Trig IN and Meas Trig Ready are enabled.

Note: The Ready for trigger is available only when the trigger source is set at External.

Choose a connector to send the VNA Ready OUT signal:

  • Backplane: (PXI) Assign PXI TRIG n as a trigger input. Trigger line setup in chassis SFP is required. See the chassis SFP manual.

  • Rear SMB: (USB VNAs) This selection is used when you use a trigger port 1 or 2 on rear panel of USB VNA

  • Trigger Ready Pins on the front panel (M937xA, P937x)

Choose Polarity of the 'Ready OUT' signal.

  • Ready High - TTL High indicates the VNA is ready for trigger. (Not available on M980xA and P50xxA)

  • Ready Low - TTL Low indicates the VNA is ready for trigger (default setting).

See Also

 

Aux Trig 1 dialog box help

See how to access the Trigger Dialog

AUX TRIG OUT and AUX TRIG IN

(M980xA, P50xxA/B, P937xB, P938xB) AUX TRIG output is also available when the port 4 of the sub side of I/O Adapter is assigned as AUX trigger output. AUX Trig 2 is not supported.

(M937xA, P937xA) This feature is not supported.

These signals are highly configurable. They can be used with all types of external devices to receive signals.

  • The Aux Trig OUT signal can be configured to be sent either just BEFORE the measurement is made or AFTER the measurement is complete. When communicating ONLY with an external source, the Aux Trig OUT signal should be sent AFTER the measurement is complete to indicate that the external source can setup for the next measurement.

Dialog Settings

The Aux Trig 1 tabs are identical. Two pair of connectors are available to allow two external devices to be controlled simultaneously.

Enable  Check to use the Aux1 or Aux2 connectors to output signals to an external device.

Channel:  This setting is controlled by a VNA Preference setting.

  • Global - ALL Aux Trig settings apply to ALL channels. The Per Point setting (see below) is made on the Trigger Setup tab which also applies to ALL channels.

  • Channel - ALL Aux Trig settings apply to the specified channel. Each channel can be configured independently.

AUX TRIG OUT (To Device)

The following settings control the properties of the signals sent out :

Polarity

Positive Pulse  Outgoing pulse is positive.

Negative Pulse  Outgoing pulse is negative.

Position

Before Acquisition  Pulse is sent immediately before data acquisition begins.

After Acquisition  Pulse is sent immediately after data acquisition is complete.

Per Point  Check to cause a trigger output to be sent for each data point.  Clear to send a trigger output for each sweep.

When the Aux Trig - "Global" VNA Preference is selected, then the Point setting is made on the Trigger Setup tab. It then applies to ALL channels. When more than one channel is present, the channel setting that was made last is used.

Pulse Duration  Specifies the duration of the positive or negative output trigger pulse.

Backplane: (PXI) Select PXI backplane trigger No.

Rear SMB: (USB VNAs) Select the trigger port number on rear panel. None: Neither port 1 nor 2 is selected.

Enable Wait-for-Device Handshake

When checked, the VNA waits indefinitely for the input line at the IO adapter (Ctrl S pin2) to change to the specified level before acquiring data. This signal indicates that the external device is ready for VNA data acquisition. If the signal arrives before the VNA is ready to acquire data, it is latched (remembered).

When NOT checked, the VNA does not wait, but outputs trigger signals when the VNA is ready.

This signal does NOT trigger the VNA.  The trigger signal is generated from Trigger Sources: Internal, Manual, or External.

IN (READY)

Positive Edge  VNA responds to the leading edge of a pulse on the Aux1 In connector.

Negative Edge  VNA responds to the trailing edge of a pulse on the Aux1 In connector.

Delay  Time that the VNA waits after receiving the Handshake input before data acquisition begins.

 

Trigger In Contrl-S:  On I/O Adapter [M98xxA,P50xxA/B,P93xxB])

Backplane: (PXI) Select PXI backplane trigger No.

Rear SMB: (USB VNAs) Select the trigger port number on rear panel. None: Neither port 1 nor 2 is selected.

See Also

 

Note: Guided and Unguided Calibration CAN be performed in External Trigger mode. With this optional behavior, while Trigger Source is set to External, trigger signals must be sent for Calibration sweeps. This behavior does not apply to FCA calibrations.

You can set a Preference to calibrate using Internal trigger signals while Trigger Source is set to External.

The following dialog box appears on the screen while waiting for an External trigger signal.

Click Abort to cancel the wait for a trigger signal.