SMU Switch Handshaking with Pulsing

[Roohcifer]

Overview
This example demonstrates how to handshake between an SMU and a switch.  Handshaking reduces test time by minimizing the downtime between switching and taking a measurement, and it is achieved by configuring the devices to send triggers to one another using PXI_Trig lines.  These triggers signal that each device's respective operation is complete and that the other device can proceed with either switching or taking a measurement.

One of the difficulties of using SMUs with switches is that SMUs can be sourcing or sinking while the switch tries to break or make new connections.  This is referred to as hot switching and can degrade the relays in the switch module.  Because of this concern, this example was written only for SMUs that support pulsing, which is a feature whereby, on receiving a trigger, the SMU will source/measure and then automatically disable its output.  In this handshaking example, we can use this feature to our advantage to achieve cold switching and protect our switch relays.

Description 

The example configures a switch with a scan list that defines the connections the switch should cycle through.  It then configures an SMU sequence, which defines what voltage or current signal to source prior to then reading back the voltage and current.  The SMU is configured to run in sequence mode, wherein multiple voltages or currents can be sourced and measured from each DUT on the other end of the connection in the scan list, such as in the case of characterizing a diode or transistor.  If you only want to source one voltage or current value (effectively running the SMU in single point mode), enter only one point in the SMU sequence.

Requirements

Software

1. LabVIEW 2012 SP1 or later
2. NI-DCPower
3. NI-SWITCH

Hardware

1. An NI Switch module that supports scanning
2. An NI SMU that supports pulsing
3. A PXIe chassis with a controller

Steps to Implement or Execute Code

All steps to execute the code are written on the front panel of the VI.  You should also read the block diagram annotations to understand the configuration and caveats of the code.

Additional Information or References

VI Snippet

**This document has been updated to meet the current required format for the NI Code Exchange.**

[Roohcifer]

I modified the sample code to be simpler and more robust and have just reuploaded the code.  Any feedback is appreciated