Sweep: Can I use an external trigger to stop a SourceMeter sweep?

The SourceMeter trigger model does not have provisions for stopping a sweep using a trigger signal. However, there is a way to accomplish this by using the SourceMeter Safety Interlock. The interlock control is accessed via the Digital I/O port. Pin 8 of the digital I/O connector is the /INTERLOCK input. You can control the interlock using a debounced switch or a TTL digital signal. To use the Interlock function, you must first enable it. From the front panel, press and release CONFIG and then press OUTPUT ON/OFF. Select INTERLOCK and then ENABLE. After enabling the interlock, exit out of the menu. The Interlock is part of the SCPI Output Subsystem. Under remote control, send "OUTPUT:INTERLOCK:STATE ON or OFF" to enable or disable the interlock.

a. Debounced Switch: Connect a switch between Pin 8 and either Pin 5 or 9 (ground pins). As long as the switch is closed, you can turn on the output and perform a sweep. As soon as you open the switch, the output will turn off and the sweep will be aborted. Both the Sample Buffer and the Trace Buffer (Data Store) are preserved and they can be read after the sweep is aborted. If you are storing data in the Trace buffer, the buffer may still be enabled when the sweep is interrupted. Be sure to disable the buffer before attempting another sweep.

b. TTL Signal: You can also use a TTL signal to control the interlock. Connect the signal high to Pin 8 and the signal low to either Pin 5 or 9. Applying a TTL low (0V) is equivalent to closing the switch and applying a TTL high (+5V) is equivalent to opening the switch. As soon as you apply a TTL high, the output will turn off and the sweep will be aborted.

Note: The INTERLOCK feature is discussed in Chapter 13 (Digital I/O Port, ...) of the Model 2400 Series User's Manual. Whether you use a switch or a digital signal to control the interlock, you should allow at least 100 microseconds settling and response time. The applied control signals (switch or TTL) should be debounced to avoid erratic operation because the Model 2400's digital I/O lines are edge-sensitive, open-collector.