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2308-900-01 Rev. A / July 2008
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Section Topics
3-19
Model 2308 Portable Device Battery/Charger Simulator User’s Manual
Section 3: Pulse Current Measurements
Pulse current digitization
The following discussion explains how to digitize a current waveform. A programming example at
the end of this section demonstrates proper command sequence for pulse current digitization.
Overall steps for digitization:
1. Sync up to desired edge for measurement.
2. After detecting edge, wait for the internal and also any user trigger delay.
OFF
ON
ON
This mode allows the user to know whether the pulse disappeared before a
user-triggered reading is requested. The responsiveness of bus commands
is governed by TOUT (if no pulses are detected), or by search time (if
pulses are detected). Therefore, the longest response time to bus
commands is approximately the greater of either TOUT or search time
values. Refer to
Figure 3-5
.
If the pulse is detected, the front panel will display DETECT HI / LO / AV on
the top line of the display. If no pulses are detected, the front panel will
display NO DETECT as well as the PTT (Pulse Trigger Timeout) bit being
set in the status model. Since the PTT bit is latched until read, a query for
the PTT bit may indicate that pulse trigger timeout occurred although the
display is showing DETECT (see
Section 7
on the status model for more
information-Model 2308 User's Manual). The bottom line may show a
previous reading or dashes based on what commands were sent previously
when in remote mode.
Checking for the parameter of PCUR TLEV command may set the PTT bit
of the status model. For triggered readings, the PTT (Pulse Trigger Timeout)
bit will be set if the reading times out and the pulse is not detected.
OFF
ON
OFF
With DETect OFF, background pulse current measurements will occur
between user-triggered readings as well as pulse detection. If the pulse is
detected, the front panel will display PULSE HI / LO / AVG on the top line of
the display along with the reading on the bottom line. If no pulses are
detected, the front panel will display “NO PULSE” as well as the PTT (Pulse
Trigger Timeout) bit being set in the status model. Since the PTT bit is
latched, a query for the PTT bit may indicate that pulse trigger timeout
occurred although the display is displaying PULSE HI / LO / AVG and a
reading (see
Section 7
on the status model for more information-Model
2308 User's Manual). Checking for the parameter of PCUR TLEV
commands to detect a pulse may set the PTT bit. If detecting pulses, the
supply's responsiveness to bus commands is affected by search time. If not
detecting pulses, the supply's responsiveness to bus commands is affected
by TOUT. Therefore, the longest response time to bus commands is
approximately the greater of either TOUT or search time (refer to
Figure 3-
5
).
In this mode, the front panel will show PULSE HI / LO / AVG on the top line
with a reading on the bottom. Checking the parameter of PCUR TLEV
commands to detect a pulse may set the PTT bit of the status model if TLEV
setting causes no pulse detection. For triggered readings, the PTT (Pulse
Trigger Timeout) bit will be set if the reading times out and the pulse is not
detected.
Table 3-4
PCURrent FAST, SEARch, and DETect commands (cont.)
FAST SEARCH
DETECT
DESCRIPTION
Shaded cells designate command with precedence in each mode.
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