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Notes on Operation
The digital inputs are sampled 10,000 times/second in the main timer ISR. (Transitions
that are so short that they are not seen in the ISR will be lost.) Each time a change in
the input bits is found, the time and the new value are written to a data buffer area.
When the data buffer area overflows, data collection is halted and an error message is
sent.
Pulse Width – Continuous Pulse Mode Syntax: {12,41 ,2 or 3,direction }
Direction
0 = low active pulse
1 = high active pulse
This mode is designed to measure the widths of pulses in a continuous stream of
pulses. Each pulse is measured. See Figure 3.
After "getting" the analog channels, send the following commands to return the data
from the CBL 2 to the host:
Command Syntax:
{12,41,3}
{12,41,0}
{12,41,.1,Start,Stop}
{12,41,.2,Start,Stop}
Notes on Operation
The Sonic Timer is used to record the time of the rising and falling edges. The
resolution is 1.6msec. At the start of the pulse the time is recorded and again at the end
of the pulses. The difference (properly scaled) is returned to the host.
38
Digital/Sonic (D0)
Figure 4. Continuous Pulse Period Measurement
Comment:
collect pulse width data in continuous pulse mode; send
before Command 3
return number of points collected on next get
statement; send after "getting" the analog channels
return @time list on next get statement
return time list on next get statement
T
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CBL 2 Technical Reference
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