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Section 4: Applications
Series 3700A System Switch/Multimeter User's Manual
Example program code for the Series 3700A
Code
Notes and comments
reset()
Reset the Series 3700A to factory defaults.
dmm.func = "dcvolts"
Set the DMM function to DC volt
measurements.
dmm.range=10
Select a range of 10 volts.
dmm.nplc=.1
Set the NPLC to 0.1.
dmm.configure.set("DCVreadings")
Save the current DMM settings as the
configuration
"DCVreadings"
.
DCvoltBuffer = dmm.makebuffer(1000)
Make buffer named
"DCvoltBuffer"
and
configure it to store up to 1000 readings.
digio.trigger[1].mode = digio.TRIG_FALLING
Set up digital I/O line 1 to detect a falling
edge trigger.
scan.trigger.channel.stimulus =
digio.trigger[1].EVENT_ID
Set each channel so it closes with a
digital I/O line 1 event trigger.
scan.bypass = scan.OFF
Set bypass to OFF so that the first channel
needs to see the trigger before closing.
scan.mode=scan.MODE_FIXED_ABR
Set the mode to fixed ABR so that the
backplane relays are closed at the start of
the scan and maintained closed throughout
the scan without being opened or closed.
scan.create("3001:3060", "DCVreadings")
Create a scan list of channels 1 to 60 on slot
3.
scan.background(DCvoltBuffer)
Start the scan to execute in the background
and save readings to a buffer called
"
DCvoltBuffer
."
Example: Optimize scan for speed
The following examples assume a Keithley Instruments Model 3723 card is installed in slot 1 of a
Series 3700A.
Some cards, such as the Model 3723, use relays that are optimized for switching speed and
reliability. However, these cards still use backplane relays, which are slow. To achieve full speed and
reliability of the card, you can avoid scan modes that intelligently open and close backplane relays,
such as
scan.MODE_OPEN_SELECTIVE
. Instead, you can set the scan mode (
scan.mode
) to
scan.MODE_FIXED_ABR
, which closes all required backplane relays before the start of the scan and
keeps them closed until you program them to open.
The following is an example of a Series 3700A configured for fast scanning with the Model 3723 card.
Sixty channels are scanned ten times on 200 V DC.
4-4
3700AS-900-01 Rev. A / July 2011