User manual

Section 8: Scanning Series 3700 System Switch/Multimeter Reference Manual
8-18 3700S-901-01 Rev. C / July 2008
-- Set up digital I/O Line 1 to detect a falling edge
trigger.
digio.trigger[1].mode = digio.TRIG_FALLING
-- Set each channel so it closes with a digio 1 event
trigger.
scan.trigger.channel.stimulus = digio.trigger[1].EVENT_ID
-- Set bypass to OFF so that the first channel needs to see
the trigger before closing.
scan.bypass = scan.OFF
-- Set the mode to fixed ABR so that the backplane relays
are closed at the start of scanning and maintained
closed throughout scanning without being opened/closed.
scan.mode = scan.MODE_FIXED_ABR
-- Create scan for Channels 1 to 60 on the card installed
in Slot 3.
scan.create('3001:3060', 'mydcv')
-- Initiate the scan to execute in the background and save
readings to a buffer called "mybuffer."
scan.background(mybuffer)
Hardware trigger modes
Use the hardware trigger modes to integrate Keithley Instruments and non-
Keithley instruments into an efficient test system. The hardware synchronization
lines are classic trigger lines. The Series 3700 contains 14 digital I/O lines and
three TSP-Link synchronization lines that you can use for input or output
triggering. The following table provides a summary for each hardware trigger
mode.
Trigger mode
Output
Input
Notes
Unasserted
Asserted
Detects
Bypass
N/A
N/A
N/A
Use the writetbit and
writeport commands for
direct line control (Version 1.4.0
and higher)
Either edge
High
Low
Either
Short input pulses can cause a
trigger overrun.
Falling edge
High
Low
Falling
Rising edge
N/A
N/A
N/A
The programmed state of the
line determines if the behavior
is similar to RisingA or
RisingM
High similar to RisingA
Low similar to RisingM