Help for Keithley LabTracer:

A. Basic Functionality
	-Example
B. Main Window
C. Definition Tab
D. Sheet Tab
E. Graph Tab
F. Options Tab
G. Troubleshooting

	A. Basic Functionality.
LabTracer is designed to allow curvetracing and characterization
of devices and circuits.  In this program SMU refers to a 
Source-Measure Unit.  Any Keithley Instruments SourceMeter
can be connected via GPIB and used as one of the SMUs. A 
maximum of 4 SMUs are used in this application, but curvetracing
requires only 2 and simple IV sweeps can be done with only one 
SMU. When connecting your SMUs to your device, make certain that
your sweeping SMU has the same GPIB address setting as shown in
the SMU1 Setup window.  Connect only the INPUT/OUTPUT HI and LO
terminals to your device. The SMU matching the address for SMU2
should be connected to bias your device using the INPUT/OUTPUT 
HI and LO terminals only.    

Example:  You want to sweep the Collector-Emitter Voltage of a 
transistor at different Emitter-Base currents and compare the 
results.  First, connect the Collector to OUTPUT HI on SMU1 and
connect the transistor Emitter to OUTPUT LO on both SMU1 and SMU2.
Now, connect the Base to OUTPUT HI on SMU2.  Once, connected in 
this application select 2 Connected SMUs from the options panel. 
Then, under the definition tab, click SMU1 setup. Enter the 
parameters for your voltage sweep including the current 
range/compliance.  Verify that the GPIB address matches your 
sweeping SourceMeter and make certain the GPIB timeout is long 
enough to complete the sweep. When your changes are completed 
click "OK". If you do not want to save your changes click 
"cancel". Now enter SMU2 setup. Depending on the type of 
transistor you may want to bias the base with current or voltage 
in the negative or positive direction. As a point of reference a 
positive current source value for the SMUmeans that current is 
forced out of the OUTPUT HI and back into the OUTPUT LO. Enter 
the appropriate values, check the parameters as you did for SMU1, 
and click "ok". After setting up both SMUs and connecting your 
device click "Execute" at the top of the main window. The percent 
complete indicator will appear and monitor progress during the 
sweep. SMU2 will bias its starting value, then SMU1 will sweep 
the voltage.  SMU2 will go to its next value and another sweep 
will occur.  This continues until SMU2 reaches its "stop" value. 
After sweeping the voltage at the "stop" value the data is 
returned to the "datasheet" on the sheet tab and the last eight 
curves are placed on the graph tab. You can watch the graphs 
update one at a time during execution. To save the "datasheet" to 
a tab delimited file go to the "sheet" tab and click save. Select 
a file name and location and your file is saved. This file can be 
opened in MSExcel, Notepad, or any spreadsheet program.  To save 
the graph go to the graph tab and click "inspect". Then under edit 
select copy. Now paste the picture into MSPaint or paste the data 
into your lab document. To save the setup so you can recall it 
later for further testing go to the "options" tab and click "save". 
Select a location and file name and your file is saved 
(*NOTE: saving the configuration DOES NOT save the data, only the 
setup. Data must be saved separately as above.).


 	B. Main Window
This section explains the displays and buttons on the main window.
"# of sweeps" = displays number of sweeps to be executed. Set bias
		points on SMU2 to change # of sweeps.
"points per sweep" = # of points in a sweep.  Defined by the sweep
		parameters in SMU1 setup.
"Execute" = Starts sweep procedure. Runs all sweep cycles before
		stopping.
"Clear Data" = Clears the graph and datasheet objects of all data.
"Abort" = During a sweep this button will halt the test after this
		step value is complete.
"Exit" = Ends program
"Keithley LabTracer" = Application title display (No function)

	C. Definition Tab
This explains the displays and buttons on the definition tab.
"change Graphic" = allows you to change the graphic being shown 
		between the SMU setup buttons. Use the graphic as
		a guide for connecting the SMUs to your device.
		You can create your own bitmaps to insert for 
		specialized testing.

"SMU1 Setup" = This opens the setup window for the Sweeping SMU. 
	"GPIB Address" = The address where SMU1 can be located.
	"Timeout(s)" = the time in seconds before an error occurs.
	"start/level" = the value at which to start the sweep. In 
		Volts or Amps depending on selected function.
	"Stop" = The last value for the sweep. units as above.
	"step" = The increment between two sweep values in Volts 
		or Amps as above.  Use negative numbers to step 
		down and positive to step up.

		*Note I: If the start and stop values can not be 
		evenly divided by the step increment a warning
		will appear and the stop value will be changed.

		*Note II: If the sign (+/-) of the step value 
		does not go toward the stop value it will be
		changed so the sweep can be completed.

	"I or V Range/Compliance" = The max allowable current 
		during a voltage sweep or the max voltage during 
		a current sweep.  These barriers protect the 
		devices and operators in case of error or 
		misconnection. This also dictates the measurement
		range used unless autoranging is selected.
	"Autorange" = This setting allows the sweeping SMU to 
		change ranges during a sweep.
	"ForceFunction"= The type of sweep either voltage or 
		current.
	"Sweep" = linear or logarithmic. Using logarithmic
		DISABLES the step parameter.

"SMU2 Setup" = This opens the setup window for the Strpping SMU. 
EXCEPT AS LISTED BELOW FUNCTION IS THE SAME AS SMU1.
	"Active Bias?" = allows user to disable this SMU during
		this test sequence.
	"Calculated # of sweeps" = a display for the sweep number.
		Can not be edited, but changes as other parameters
		alter the sweep count.
	"ForceFunction"= The type of source stepping sets to 
		either voltage or current.

		*NOTE: Autoranging is only available on SMU1.

"SMU3 Setup" = This opens the setup window for the SMU. 
EXCEPT AS LISTED BELOW FUNCTION IS THE SAME AS SMU2.
	"Level" = level is the source value for this SMU.
		
		*NOTE: This SMU does not sweep or source multiple
		values during one cycle.  It is best used as a 
		constant source or a forced Ground depending on 
		the needs of the device.

"SMU4 Setup" = This opens the setup window for the SMU. 
BUTTONS FUNCTION THE SAME AS ON SMU3.

"Data Configuration" = This window allows you to set the timing
	and data collection for the test. Set the NPLCs (number
	of power line cycles) to a rate for integrating your 
	measurement in terms of the power line cycle. For instance,
	1 NPLC means that the measurement is averaged over 16.6 ms
	when on a 60 Hz power line. The larger this number the more
	accurate the measurements will be, but the longer they will 
	take.

"Delay" = This is the settling time between source and measurement. 
	The longer this period the better the measurement. Whatever
	time you enter is added to each measurement.

"Source Ranging" = The range setting used for the force function. 
	The SourceMeters can source closer to the assigned value in
	the smallest range, but setting a best fixed range gives you
	more consistent timing.

Data buttons = A test returns only the data selected on this window.
	If an SMU is not in use or disabled on its setup panel, then 
	the data buttons will not be enabled. You can also select 
	a timestamp and a formula to be returned. If you select the 
	formula continue by clicking on the formula button and 
	defining your formula.

Formulator Window
	This formula window lets you input a formula that will return
	data you can see in the table or graph. You can use any 
	active data series (i.e. SMU1 Voltage) and any Testpoint
	function. To see a list of functions open TESTPT.HLP in the
	install pack for this software. Some functions are listed on
	this page. By clicking the button the correct syntax for the
	formula call is appended to your formula string.

*On all these windows OK saves changes and returns you to the
previous window while CANCEL returns values to their previous
state before closing the window.


	D. Sheet Tab
This sheet displays the data from a test.
	"SAVE DATA" = saves data to a tab delimited file.
	"DataSheet" = actual spreadsheet for the data.
	
	E. Graph Tab
This tab displays the graphs of the last 8 sweeps of data collected.
	"INSPECT" = This button opens the graph so you can zoom,
		print, or copy it to the clipboard.  Simply,
		close the graph window when you are done.

	F. Options Tab
This tab offers general options for application management.
	"Connected SMUs:" = select # of SMUs you have connected
		to the PC running the software.
	"save as" = allows user to save the configuration as a file.
	"open test file" = open a configuration from a saved file.
	"help" = accesses this help file.

	G. Troubleshooting
This is a list of common error messages:
	
	*After receiving any error it may be necessary to reboot 
		the SourceMeter before continuing. This will
		clear the error and make corrections possible.
	
	"GPIB Timeout" = The SMU did not respond to a command.
		Double check that the GPIB address set in setup
		matches the address the SMU is set to use. Read
		your manual to change GPIB address of the 
		instrument. Also, the instrument could be in the 
		middle of a sweep and did not finish before the
		timeout period expired. If so, simply click retry 
		when the SMU is done taking readings. If the 
		triggerlink cable is not properly connected between
		all SMUs, then they will not complete the test and 
		will freeze mid cycle. To correct this reboot the
		instruments, cancel the timeout error and setup 
		the instruments again after properly installing the
		triggerlink cable. Lastly, make sure the GPIB 
		cables are firmly attached to both the SMUs and 
		the PC.	If you have disconnected or changed the
		GPIB address of instruments after starting this 
		application then cancel and setup the SMUs again.

	"Divide by zero" or "Math function error"
		This is a very common error caused by an
		incorrect variable or formula. If you see this 
		error when running a test, that means that the
		formula is turned on and either not defined or
		not correctly defined. You can ignore this error
		continue your test. To eliminate the error either
		turn off the formula or redefine it according to
		the function syntax defined in the TESTPT.HLP
		file in the install pack. This error can also 
		occur on a limited range function like the 
		natural log. If your formula takes the natural
		log of data that is negative the program will 
		throw a range error like this and warn you that
		it put zeros in for the answer.	
			If you see this error in the SMU setup 
		windows it usually means you are using a 
		logarithmic sweep and the range error is
		stopping the program from calculating the 
		sweep parameters. You can ignore this message
		and then go fix the bad data. You can NOT 
		perform a logarithmic sweep that begins or ends
		at or below zero.

	"No GPIB Board Present" = Your GPIB card is not 
		installed correctly or your GPIB card is not 
		compatible with this software version. Call 
		Keithley Instruments (1-888-KEITHLEY) for further 
		support or visit www.keithley.com.

	"At least 1 SMU has never been initialized." and "You have
		opened setup but not made any changes." =
		These errors mean that the test was executed before
		all SMUs were in a proper configured state. The
		test will continue using the last settings saved or
		you can cancel the test and make more changes.

List of possible problems:
	
	1> My source does not sweep all the way according to the
		data or the graph.  It is being limited.

		>Check the range/compliance value for each SMU. 
		Your measurement can never go above this value
		even with autoranging on.  Your source stopped 
		increasing its output when it went into compliance.

	2> My measurement accuracy is not good enough. How can I 
		improve it?

		>If this is happening on SMU1 try using autoranging.
		This will give you the best measurement at each
		point.  On the other SMUs lower the compliance 
		value until the data improves. It may be necessary to
		divide your sweep into portions using different 
		ranges. Data may also be improved by selecting a 
		higher value for either NPLCs or delay in the data
		configuration window.

	3> The SourceMeter beeps and sends an error when I 
		configure it.
		
		>The two causes for this are either the instrument is
	in an unstable state or one of the parameters you are
	sending it is outside it's capabilities. Power cycle 	
	the SourceMeter and set it up again. If you still get
	the error, then compare the parameters with the 
	specifications of your instrument found on page 3.3
	of your manual.  For instance, the 2400 has a maximum 
	source voltage at 210 V with a maximum compliance of 
	105 mA or 21 V at a compliance of 1.05 A. As a voltage 
	source, the parameters must be in +/- 5 microV 
	increments which means the lowest non-zero source 
	voltage for a 2400 is .000005 V.  The lowest current 
	source level is +/- 50 pA. To source smaller levels 
	you need a 6430 or other more sensitive SourceMeter.

	4> How can I make a Gummel Plot using this software?
	
		>To make a Gummel plot where you would typically
	sweep 2 SMUs simultaneously using Labtracer you need to set
	the sweeping SMU on the devices third contact and by 
	holding the other two points at bias levels you can 
	create the same effect on the device. Simply adjust 
	the sweep so that the correct potentials appear on the
	device.  

	5> I see oscillations in my measurements, what is 
		happening?
		
		>This is usually the effect of using the 0.01 or
	0.1 NPLC setting in data configuration. These settings
	give you faster measurements but the tradeoff is the 
	instrument can not as easily reject the noise from the
	power line (50 or 60 Hz). Depending on the signal level
	this may cause oscillations in your data. Also, make 
	certain the SourceMeter are grounded to the same outlet.
	Differences in the grounding or floating the grounds 
	will greatly increase these oscillations.

	6> The data I'm saving isn't getting saved over the old
		data I am replacing. Where is it?

		>The data is appended to the files. Data is not
	routinely overwritten in this program. Scroll down in 
	notepad or Excel to find the header for the data you
	want to inspect.