Keithley 2302 Instruction Manual page 114

4-18 Long Integration Measurements
Table 4-3
FAST, SEARch, and DETect command reference (cont.)
FAST SEARch DETect
OFF ON OFF
Shaded cells designate command with precedence in each mode.
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
TestEquipmentDepot.com
With DETect OFF, background long integration measurements will occur between user-
triggered readings as well as pulse detection. If the pulse is detected, the front panel will
display "LONG INT" on top line of 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
(see section 8 on Status Model), a query for the PTT bit may indicate that pulse trigger
timeout occurred although the display is displaying LONG INT and a reading. Check-
ing for the parameter of LINT TLEV commands to detect a pulse occurs by looking for
a rising edge. This may set the PTT bit. If detecting pulses, the supply's responsiveness
to bus commands is affected by search time plus reading time. If not detecting pulses,
the supply's responsiveness to bus commands is affected by TOUT. Therefore the long-
est response time to bus commands is approximately the greater of either TOUT or
search time plus reading time (refer
set to RISING or FALLING.
If TEDGe is set to NEITHER, pulse detection will fail since synchronization to an edge
for triggering does not occur (there is nothing for the unit to detect). In this mode, the
front panel will show LONG INT on the top line with a reading on the bottom. The user
will have to determine if the pulse was present for the reading or not. In this mode, the
PTT bit of the status model will not be set as well and therefore, not useful. Since check-
ing the parameter of LINT TLEV commands to detect a pulse looks for the RISING
edge, this may set the PTT bit of the status model if TLEV setting causes no rising edge
pulse detection.
Description
Figure 4-3). This functionality occurs if TEDGe is