Omega Engineering OMB-CHARTSCAN 1400, User Manual

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Appendix B Configuration Aspects for Programmers
ChartScan User’s Manual B-3
Measuring Modes
Overview
You can select either of two scanning modes for ChartScan, 1) Normal mode, or 2) High-speed, single-channel
mode (Burst Mode).
ChartScan Measuring Modes
Mode “Average weight”
Setting
Application
Normal 16, 32, 64, 128, or
256 Recommended for AC noise rejection.
1, 2, 4, or 8 Recommended for high-speed, multiple channel applications for thermocouples
and DC voltages where noise filtering is not an issue.
High-speed,
single-channel not selectable High-speed, single channel applications for AC and DC voltage post-acquisition
waveform analysis
In the Normal mode , ChartScan samples channel data at 1.92 kHz, or once every 520.83 µs. You can select the
average weight ( number of samples to average ) to provide noise filtering, as discussed later in this section.
In the High-speed, single channel mode , ChartScan collects data in user-defined multiples of 256 samples at a
sampling frequency within the range of 38.5 Hz to 20.0 kHz.
Aside from selecting ChartScan’s scanning mode, and setting the mode parameters from ChartView software
(see Chapter 4,
ChartView and ChartView Plus ), the following commands can be used. Note that Appendix A
contains more detailed information regarding these commands.
Mode-Related Parameter Commands
Command Syntax Function
M# M#mode
Set Measuring Mode.
Options for mode are:
0
- Normal mode , and
1
- High-speed, single channel mode .
W# W#wt
Set Averaging Weight.
Specify the number of samples to average in Normal mode , where
wt
is the
averaging weight. Options for
wt
are: 1, 2, 4, 8, 16, 32, 64, 128, and 256, with 32
being the default.
F#
F#freq
Set frequency for High-speed, single channel mode .
freq
must be a value for Hz such that 38.5 <
freq
< 2000. The default is 2000
Hz.
Y Ypre,post,stop
Or
Set Counts or Select Blocks.
In Normal mode - This command is used to set acquisition counts where
pre
is
the pre-trigger count,
post
is the post-trigger count, and
stop
is the post-stop
count.
Y0,count,0
In High-speed, single channel mode (burst mode) the
post
position serves as
count. count is used to select the number of 256 sample blocks to be collected.
Options for block count are dependent upon system memory as follows:
256Kbytes, count value allowed is: 2 to 512
1 Mbyte, count value allowed is: 2 to 2048
4 Mbytes, count value allowed is: 2 to 8192
8 Mbytes, count value allowed is: 2 to 16384
Note: In each case the number assigned for block count must be a power of 2.
U16 M#modeF#freqW#wt
Query the Measuring Mode.
This command queries the following three parameters:
M#
,
F#
, and
W#
.
U17
U17
Return RMS.
This command computes and returns the root mean square (RMS) value of the
last completed
high-speed, single-channel mode acquisition.