Keithley 6220 Reference Manual page 160

5-40 Delta, Pulse Delta, and Differential Conductance Model 6220/6221 Reference Manual
Fixed output settings
These following parameters are set from the CONFIG PULSE DELTA menu that is
accessed by pressing the CONFIG key and then the PULSE key.
I-Hi and I-Lo
These settings specify the high and low level of the pulses. Each high pulse
returns to the programmed low pulse level. Both I-Hi and I-Lo can be set from
-105mA to +105mA. The default setting for I-Hi is +1mA, and the default for I-Lo is
0mA.
Width and source delay
The pulse width specifies the time period that the output remains at the high and
low pulse levels. Pulse width can be set from 50µs to 12ms. The default setting for
pulse width is 110µs.
The source delay is used to allow the pulse to settle before triggering the Model
2182A to perform a measurement conversion (A/D). Source delay can be set from
16µs (default setting) to 11.966ms.
Pulse width and source delay are shown in Figure 5-12. Note that the set pulse
width and source delay determines the integration rate (measure speed) of the
Model 2182A. Integration rate is automatically set when Pulse Delta is armed.
Count
The Pulse Delta count specifies the number of Pulse Delta intervals to perform.
Each pulse interval yields one Pulse Delta voltage reading. A finite number (1 to
65,536) can be set or count can be set to Infinity. With Infinity set, Pulse Delta will
run continuously. The default setting for count is Infinity.
Ranging
For Pulse Delta, the source range can be set for BEST (default setting) or FIXED.
With BEST ranging selected, the Model 6221 will select the optimum (lowest)
range that will support both the low and high pulse levels. For example, if pulse
low is -12mA and pulse high is 10mA, then the 100mA source range will be used.
With FIXED ranging selected, the source remains on whatever range is presently
selected before arming Pulse Delta. If the selected range is too low, error -221
Settings Conflict will occur.
For remote programming, there are two separate commands to set range. Use the
SOUR:PDEL:RANG command to set range for a fixed output and use the
SOUR:SWE:RANG command for the pulse sweep output. Details on these com-
mands are provided in Table 5-4.
Return to Section 5 topics
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