Pulse Timeout - Keithley 2302 Instruction Manual

4-4 Long Integration Measurements
Trigger level
Before a rising or falling pulse edge can trigger the start of a long integration, the pulse must
first be detected. Trigger level specifies the minimum pulse level that will cause detection. For
example, if the trigger level is set for 2A, pulses that are ≥2A will be detected. Current pulses
<2A are ignored.
The charger channel has only one trigger level range: 0–5A. For the Models 2306, 2306-VS,
and 2306-PJ on the 5A current range, the battery channel has three trigger level range settings:
5A, 1A, or 100mA trigger level ranges. For 5A, the level may be set from 0 to 5A. For the 1A
range, the trigger level may be set from 0 to 1A. Likewise, the level may be set from 0 to 100mA
for the 100mA trigger level range. On the Model 2306-PJ, you can also measure on the 500mA
current range. Therefore, the 2306-PJ has three additional trigger level range settings for the
500mA current range: 0-500mA, 0-100mA, and 0-10mA. These ranges affect trigger level
resolution and not the current range since long integration readings are always performed on the
5A current range. The trigger level range option on battery channel allows the user to set a
trigger level with greater resolution.
Trigger level range
This setting affects long integration trigger level and has no affect on current range setting
since long integration measurements are always performed on the 5A current range. For the
Models 2306, 2306-VS, and 2306-PJ on the 5A current range, three settings (battery channel
only) are available: 5A, 1A, or 100mA. Use the range that provides adequate trigger level
resolution (a 100mA range provides a greater available resolution for trigger level than does the
1A range). When using the Model 2306-PJ's 500mA current range, the three trigger level range
settings are: 500mA (0.5mA step), 100mA (0.1mA step), and 10mA (0.1mA step).

Pulse timeout

TOUT (timeout) specifies the timeout length for the pulse. When the TOUT value is reached,
NO PULSE is displayed (top line of the front panel display). Set the value for TOUT as follows:
TOUT = LINT TIME + x
where x makes TOUT > LINT TIME
TOUT = timeout (time allowed for detection of a pulse)
LINT TIME = long integration time (time allowed for reading after pulse occurs)
For example, if the trigger edge is set to rising, the timeout value should be set to allow suf-
ficient time for detection of the pulse if the rising edge is just missed. In
the point where we start looking for the pulse. Since the rising edge was just missed, point (B)
will be the first detectable rising edge. If the timeout is less than long integration time, a pulse
trigger time out (due to TOUT) may occur. Therefore, if long integration time = 1.8 seconds, a
good TOUT value would be 2 seconds. A similar method for selecting a TOUT value would be
to use a value equal to 105% of the expected pulse period.
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Figure 4-2, point (A) is