Using Front Panel Set-Ups; Store Set-Ups; Recall Set-Ups; Using The External Reference - Keithley 776 Instruction Manual

Operating Instructions
3-20. Using Front Panel Set-Ups
Setting up all parameters in a versatile instrument such
as the Model 776 may takes some time. The set-up time
is even longer when more than one set-up is required.
Model 776 incorporates a battev backed-up non-vola-
tile memory that preserves stored information up to
three years. It is possible to store complete front panel
set-ups in 10 different memory locations which are built
into the instrument especially for this purpose.
3-20-l.
Store
Set-Ups
First modify the front panel parameters as necessav to
perform your tasks. When all parameters are set and
checked. proceed to store this set-up as follows:
1. Depress the [ST01 push button and observe that the
display is modified to indicate the following:
StorE ?
(? appears flashing)
This reading indicates that the instrument is ready to
receive one memory location where front panel set-up
is to be stored. Set-ups may be stored in locations 0 to
9. Depressing [STOJ again cancels this function and the
instrument resumes normal operation.
2. Select one memory location from 0 to 9 and depress
the button which is marked with the selected number.
The instrument displays the following for one second:
StorE D
(Where D is the selected memory location)
This display indicates that the function generator
acknowledges the entered memom location. The instru-
ment then resumes normiil opcraiion.
3-20-2. Recall Set-Ups
Turning AC Mains power off does not affect the stored
data in the RAM. Therefore. front panel set-up which
were previously recorded by the user remain presened.
To recall a front panel set-up proceed
as follows:
I. Depress the [RCL] push button and observe that the
display is modified to indicate the following:
rEcALL ?
(?
appears
flashing)
This reading indicates that the instrument is ready to
recall the memory location where front panel set-up was
stored. Depressing the [RCLI button cancels this func-
tion and the instrument resumes normal operation.
2. Select one mcmo~ location from 0 to 9 so as to recall
the desired set-up. and depress the button which is
marked with the selected number. The instrument dis-
plays the following for One second:
rEcALL D
(Where D is the selected
memory location)
The instrument then recalls the parameters that were
previously stored in the selected memory location and
updates front panel indicators with the recalled parame-
ters.
3-22. Using An External Reference
Generally. Model 776 provides two accuracy grades for
the internal time base: stabilized clock. or an optional
temperature compensated crystal oscillator (TCXO).
The best accuracy. over the specified temperature oper-
ating range. that may be achieved with the TCXO is I
PPM. or 0.1 PPM -accuracy which will satisfy the most
demanding requirements. With special applications.
however. where such inaccuracies may become a limil-
ing factor. an external reference ma) provide a better
solution. An EXT REF comiector is available on the rear
panel. However. before applying an esternal rcfcrcncc
signal. it is first neccssaq to open the top cover and
change a switch setting. The procedure of changing this
switch is given in Section 5 of this manual.
3-23. Changing GPIB Address
GPIB address is modified using front panel program-
ming. The non-volatile memov stores the GPIB ad-
dress. Conventional address switches are not provided.
Detailed instructions how to change the GPIB address
are given in Section 4 paragraph -i-7.
3-11