Omega Vehicle Security 1400 manual High-Speed, Single-Channel Mode Burst Mode, Condition

Appendix B Configuration Aspects for Programmers

High-Speed, Single-Channel Mode (Burst Mode)

The High-speed,single-channel mode, also known as burst mode, is used for post-acquisition waveform analysis of AC and DC voltages. In this mode, ChartScan can sample from 38.5 Hz to 20.0 kHz, and store the data in memory. Note that ChartScan’s memory can be expanded up to 8 Mbytes.

When performing post-acquisition waveform analysis, such as Fast Fourier transforms, ChartScan can return each data point in a waveform. In addition, ChartScan can provide the true RMS value of an AC voltage. Because high sampling rates can be achieved in the High-speed,single-channel mode, the conditions indicated in the following table apply.

High-Speed, Single-Channel Mode

Necessary Item Conditions Due to High Sampling Rates

Item	Condition
High/Low./Last registers	Disabled
Alarms	Disabled
Trigger Start	Software trigger only (@ command)
Trigger Stop	By Count only
Pre-Trigger	Disabled
Post Stop Count	Disabled
Time Stamping	Disabled
Alarm Stamping	Disabled
Digital Input Stamping	Disabled
Averaging weight	256, forced default (can not be changed)
Frequency	In regard to AC voltage, frequency must be such
	that it results in a sufficient whole even number of
	samples per line cycle.

ChartScan collects samples for the selected channel in blocks of 256 samples in one time increment. This appears similar to a scan of 256 channels while in the normal (multiple-channel) mode since you must …

•program the number of 256 sample blocks to acquire in the post trigger count parameter of the Y command, and will

•retrieve the data from ChartScan as “post trigger count” scans of 256 samples

Note: High-speed,single-channel mode is a “one-shot” operation. It permits ChartScan to collect the specified number of samples, then stops. The mode is not continuous, nor does it allow for memory overflow and wrap-around. The maximum number of samples is limited by the amount of memory available. See the Y command reference (in Appendix A) for related information.

Note: In regard to AC voltage measurements, ChartScan only supports AC voltages having an input signal frequency which is an integer multiple of the AC line cycle. In order to compute an accurate RMS value you must program a frequency which will yield a sufficient “whole even number” of samples per line cycle.

Note: In High-speed,single-channel mode, upon completion of the acquisition, AC voltage RMS values can be retrieved with the U17 query command.

To use the High-speed,single-channel mode use the following commands, or use ChartView (see Chapter 4). Note that these commands (or ChartView equivalent) are all that is needed to initiate the High-speed, single- channel mode data acquisition.

M#1	‘Select high-speed, single-channel mode
Cchan#,type	‘Select channel number and voltage-range
F#freq	‘Select sampling frequency where 38.5 < freq < 2000.0
Y0,count,0	‘Select count where count is the number of 256 sampling
	blocks to be acquired
T1,8,0,0	‘Arm the system to start on @, stop on count
@	‘Start the acquisition

The remainder of this appendix and the next, pertaining to acquisition setup, refers to normal mode acquisitions only.

ChartScan User’s Manual B-5