Specifications

62 Using the DMM and ARB Chapter 4
Triggered Voltage Measurement
The Agilent E1411B Multimeter (DMM) can be triggered by a signal on the
VXI Mainframe’s backplane. This signal uses one of the TTL (i.e., TTL0 to
TTL7) trigger lines.
How to Trigger the
DMM
Testplan ‘dmmtrig.tpa’ shows how the DMM is triggered using the
Agilent E6174A Arbitrary Waveform Generator (Arb). The Arb is also used
to generate the signal measured by the DMM. The testplan also
demonstrates how to use the Agilent E6171B Measurement Control
Module’s (MCM) analog comparator. The testplan is in the following
directory:
C:\Program Files\Agilent\TS-5400 System
Software\testplan\examples
The Arb generates a ±5V 10 Hz square wave as the trigger signal. This
method uses the analog comparator of the MCM to send the trigger to the
DMM using the VXI Mainframe's backplane (see connections in Figure 4-1
and Figure 4-2).
The testplan configures the MCM analog comparator to trigger at 0 volts.
Setting the “trigedge” parameter in the “viConfCompare” action to “0”
(positive edge detection), causes negative going backplane trigger when the
input signal makes a low to high (positive going) transition through the
trigger threshold. Setting the “trigedge” parameter in the “viConfCompare”
action set to “1” (negative edge detection), causes triggers when the input
signal makes a high to low (negative going) transition.
The following is a review of the testplan
Test/Action Name Description
test: Dmm Init Initializes the Digital Multimeter.
dmmConfCal Disables autozero and set the power line frequency.
dmmIsSet Waits for setup to complete.
test: Arb 1 pgm Configures Arb and outputs a 10 Hz +5V Square wave.
arbReset Reset the Arbitrary Waveform Generator (Arb) to its turn-on state.
arbConfOutControls Configures the Arb’s output circuitry.
Arb_Dl_Std_Waveform Download a 10 Hz square wave into the Arb.
arbInitiate Start outputting the waveform.
Arb_Select_Wave_By_Name Select waveform downloaded above.
test: VI Config0 (+5) Configures MCM’s analog comparator to trigger at 0V and a low to high (positive
transition) trigger.
viConfCompare Configures the comparator. The “trigedge” parameter value (0) causes a
backplane trigger when the input signal makes a low to high (positive going)
transition trough trigger threshold.
viIsSet Waits for setup to complete.
Test: Meas V - Trigger Trigger DMM and measure trigger voltage.
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