Tabor Electronics 5251, User Manual

Page: 151 / 298

4
Remote Programming Reference
Instrument Control Commands
4-17
Parameters
Name Type Default Description
INTernal Discrete INT Selects an internal source. The internal source could
be either the standard 100ppm oscillator, or the
optional 1ppm TCXO
EXTernal Discrete Activates the external reference input. An external
reference must be connected to the 5251 for it to
continue normal operation
Response
The 5251 will return INT, or EXT depending on the present 5251 setting.
FREQuency{<freq>|MINimum|MAXimum}(?)
Description
This command modifies the frequency of the standard waveforms in units of hertz (Hz). It has no affect on
arbitrary waveforms.
Parameters
Name Range Type Default Description
<freq> 10e-3 to
100e6 Numeric 1e6 Will set the frequency of the standard waveform in
units of Hz. Although the display resolution for the
frequency setting is 9 digits only, the frequency
command can be used with resolutions up to 14
digits. The accuracy of the instrument however, can
only be tested to this accuracy using an external
reference that provides the necessary accuracy and
stability
<MINimum> Discrete Will set the frequency of the standard waveform to
the lowest possible frequency (10e-3).
<MAXimum> Discrete Will set the frequency of the standard waveform to
the highest possible frequency (100e6).
Response
The 5251 will return the present frequency value. The returned value will be in standard scientific format (for
example: 100mHz would be returned as 100e-3 – positive numbers are unsigned).