When cascading SMUs, you can still take advantage of the remote sensing feature to ensure that the increased voltage is accurately seen at the DUT. However, the lead connections will be different than those that are made when using a single SMU.
Measurements made using remote sense traditionally require 4-wire connections from the SMU to the DUT, seen in the image below. In a remote sense configuration, one set of leads carries the output current, while another set of high input impedance leads is used to measure voltage directly at the DUT terminals, as illustrated in Figure 1. The SMU will maintain the desired output voltage at the Sense leads by increasing the voltage at the output to compensate for voltage drops due to lead resistance.
Remote sense can be enabled or disabled using the niDCPower Configure Sense VI on a per output basis for channels that support this feature.
Figure 1: Remote Sense connections for one SMU
Remote Sense Connections for Cascaded SMUs
Measurements made using remote sense with cascaded SMUs will still require 4-wire connections for each SMU. However, the connections will be made as seen in Figure 2.
Figure 2. Remote Sense Connections when using two SMUs, here two PXI-4132s.
Considerations for wiring remote sense:
Figure 3: Remote Sense and Ground connections when cascading more than two SMUs
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