Example #2 - VTI Instruments EX1000A User Manual

VTI Instruments Corp.

Example #2

This example demonstrates a typical setup sequence for a transient monitoring application with an
alarm. The requirements of the application are:

Input connections are 48 type E thermocouples connected to channels 0 through 47.

The temperatures to be monitored are transient in nature, such that the 1 kHz filter frequency
is suitable.

Measurement data is required to be in units of ºC.

Timestamp reporting is desired, but CJC temperature reporting is not.

Data is to be acquired at a rate of 1000 readings/second for 10 seconds, triggered by a positive
edge transition on channel 0 of the trigger bus.

Once the 10 seconds of data is collected, the test is complete.

DIO Channel 7 is to be used as an alarm indication, in which it needs to transition low if any
of the 48 channels exceeds 50 ºC.
The exact steps to be performed to satisfy this application are:
Configure the Scan List
The scan list is configured with the Scan List...Configuration page. Click the Enabled link to
enable all 48 channels. Since all channels require the same EU conversion, click the E link. Click
the Apply button to accept the changes.
Configure the Filter Frequencies
The filters are configured with the Scan List...Filters page. Since all channels require the same
filter setting, click the 1 kHz link. Click the Apply button to accept the changes.
Configure the FIFO
The FIFO is configured with the Data...FIFO Configuration page. Select the Temperature Units
selection of C. Uncheck the Report CJC Temperatures checkbox. Check the Report Timestamps
checkbox. Click the Apply button to accept the changes.
Configure the Trigger Model
The trigger model is configured with the Trigger...Configuration page. Click the Default button.
Expand the Arm branch to expose the Arm source. Deselect any currently checked sources. Expand
the VTI Trig. Bus branch and select Pos. Edge of VTB Channel 0. Within the Trig source, select
Timer. Set a TRIG Count of 10000. Enter a Timer Interval of 0.001. Uncheck the Init
Continuous checkbox. Click the Apply button to accept the changes.
Configure the Limit System
Limit conditions are configured with the Limits...Limits page. Using the Set pull-down selection,
select Set: 0. For channels 0-47, check the Manual checkbox and enter an upper limit value of 50.
Click the Apply button to accept the changes. These limit conditions are linked to the DIO channel
through the Limits...DIO Limit Events page. Using the DIO Channel pull-down selection, select
channel 7. Since all channels are required in the limit evaluation, click the Set 0 Upper All link.
Check the Invert checkbox. Uncheck the Latch checkbox. Click the Apply button to accept the
changes.
Initiate the Trigger Model
The acquisition sequence is initiated with the Trigger...Initialize page.
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