DH Instruments COMPASS FOR MOLBOX, User Manual

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COMPASS

for molbox™ User’s Manual
Page 19
© 1998-2003 DH Instruments, Inc .
5.1.3 EXAMPLE #3
“How do I use my HP34401A DMM to measure the DUT output?”
The HP34401A is a popular high accuracy Hewlett Packard multimeter that has an IEEE-488 and
RS-232 interface. To read a voltage from this DMM, the command “MEAS:VOLT:DC?” must
be issued. This example demonstrates the basic requirements of setting up a DMM for DUT
data acquisition in the Hardware Definition
.
5.1.3.1 DUT DEFINITION SETUP
The only requirement for DUT to be tested using an external DMM is that the output type
of the DUT be
<Voltage/Current> in the [Read] tab of the DUT Definition (see Section 8.5.8).
5.1.3.2 DMM CONFIGURATION SETUP
Use [Setup] , [Hardware] , then select the [DMM] tab and click <New> to create
a new DMM (see Section 10.3.4). Enter the basic DMM setup information at the
top of the form. This particular DMM supports both RS-232 and IEEE-488 interfaces.
In this example IEEE-488 is used. If RS-232 were chosen, it is possible to use the
<Ref Com2> option to use the COM2 port of the reference molbox to communicate
with the DMM. Select “Voltage (V)” from the <Output Units> field. Then press the
<Read Commands> button. This displays the remote command Editor. Enter
“MEAS:VOLT:DC?” in the command field then press <OK> to store the setting
and return to the DMM Editor. Now is a good time to find the command to read
current so there is no need to re-configure this DMM in the future. Select “Current (A)”
from the
<Output Units> field then again press the <Read Command> button.
Enter “MEAS:CURRENT:DC?” in the first field then press <OK> . This is the command
to read current in Amps should it be needed later. There are no leading characters
to strip and the command terminator is carriage line feed. Press
<OK>
to save this DMM. This Hardware Definition provides COMPASS with the
necessary information to use a DUT that outputs in V, mV and/or mA.
Figure 7. Example 2, DMM Setup
Access the System Configuration using the [Setup] , [System] menu (see Section 10.2).
Select this DMM as the <DUT Output DMM> . Click <Close> to store the
configuration and return to the main program.