Rangex - Keithley 4200A-SCS Reference Manual

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Model 4200A-SCS Parameter Analyzer Reference Manual

rangeX

This command selects a range and prevents the selected instrument from autoranging.

int rangei(int instr_id, double range);

int rangev(int instr_id, double range);

Use the rangeX command to eliminate the time required by automatic range selection on a

measuring instrument. Because the rangeX command prevents autoranging, an overrange condition

can occur (for example, when measuring 10 V on a 2 V range). The value 1.0e+22 is returned when

this occurs.

The rangeX command can also reference a source, because a source-measure unit (SMU) can be

either of the following:

Simultaneously a voltage source, voltmeter, and current meter.

Simultaneously a current source, current meter, and voltmeter.

The range of a SMU is the same for the source and the measure commands.

Compliance limits – When selecting a range below the limit value, whether it is explicitly programmed

or the default value, an instrument temporarily uses the full scale value of the range as the limit. This

does not change the programmed limit value, and if the instrument range is restored to a value higher

than the programmed limit value, the instrument again uses the programmed limit value. See

Compliance limits

When changing the instrument range, be careful not to overrange the instrument. For example, a test

initially performed on the 10 mA range with a 5 mA limit is changed to test in the 1 mA range with a

1 mA limit. Notice that the limit is lowered from 5 mA to 1 mA to avoid overranging the 1 mA setting.

When source mode of the SMU changes, the measure range may change. This change minimizes

variations in the SMU output level. The source mode of the SMU refers to its voltage sourcing or

current sourcing capability. Changing the source mode means using a command (such as forceX) to

change the SMU mode from forcing voltage to forcing current (or from forcing current to forcing

voltage). For example, if the SMU is programmed to force voltage (forcev), and then is programmed

with to force current (forcei), to ensure a consistent output signal, the previously programmed

current measure range may change. Make sure the correct measure range is set by sending the

rangeX command after switching the source mode. The commands that can change the source

mode are asweepX, bsweepX, forceX, pulseX, searchX, and sweepX.

4200A-901-01 Rev. C / February 2017

The instrument identification code

The value of the highest measurement to be made (the most appropriate range for

this measurement is selected); if range is set to 0, the instrument autoranges

(on page 3-3) for more information.

Section 13: LPT library function reference