12
5. On the left panel, use the slider to find the Register called REC_PRD. Use the pointer to
select this register after which the register name will appear in the top center of the
Register access window. Enter “2” in the New Hex Value entry and push the “Write” button.
This configures the device for an automatic repeat time of 2 seconds.
6. Press Start, observe FFT Frequency Graphs displays. The capture with AVG_CNT set to
2 and FTF_AVG1 SR0 set to 2 will take approximately 1.8 seconds and will be repeated
every 2 seconds.
Manual FFT (MFFT) Capture Mode
MFFT mode can be used to manually trigger a capture to create a single FFT record with 2048
bins and allows various configuration options.
Manual FFT Capture Example
The following steps configure the ADCMXL for a manual FFT mode repetition rate of 8 seconds
1. Select “Manual FFT” from the Mode Selection pull down menu.
2. Open Register Access Window.
3. On the left panel, use the slider to find the Register called AVG_CNT. Use the pointer to
select this register after which the register name will appear in the top center of the
Register access window. Enter “05” in the New Hex Value entry and push the “Write”
button (this will set the time average to 2
5
). Note: this will set the AVG_CNT for SR0, which
is the default Sample Rate configuration.
4. On the left panel, use the slider to find the Register called FFT_AVG1. Use the pointer to
select this register after which the register name will appear in the top center of the
Register access window. Enter “108” in the New Hex Value entry and push the “Write”
button.
5. Press Start, observe FFT Frequency Graphs displays. The capture with AVG_CNT set to
5 and FTF_AVG set to 8, will take approximately 8.4 seconds. There will be only a single
capture.
Manual Time Capture (MTC) Mode:
When operating in MTC mode, the ADcmXL captures 4096 consecutive time domain samples.
These samples are displayed only after all configured averaging and filtering on the data set are
completed.
Manual Time Capture Example
These step by step instructions will demonstrate a basic Manual Time Capture and then a second
capture after Auto-nulling.
1. Set Manual Time Capture under the “Mode Selection” Pull Down Menu
2. Press Start; a Manual Time Capture will initiate and complete within a few seconds. If
there is no stimulus (vibration or mechanical movement), 3 flat lines should appear in the
3 plots. In some cases, the flat line will be off the plot dimensions. The Y-Axis magnitude
can be changed by right clicking in the window, pressing the “>” will increase the full-scale
magnitude of the Y-Axis. Pressing the “<” will decrease the full-scale magnitude of the Y-
Axis.
3. Open Register Access Window
