Racal Instruments 3156B, Руководство пользователя

Страница: 67 / 385

3156B User Manual
Racal Instrument © 2005 Using the Instrument 3-17
The 3156B was designed in a way to allow different waveforms and functions
to be output from each channel, for example, if channel 1 is programmed to
output an arbitrary waveform, the other channel can be programmed to
output sequenced waveforms. However, since there is only one clock source
in the instrument, there are some function combinations that will not be
possible to run simultaneously on both channels and if programmed so will
issue a setting conflict error message. The inter-channel dependencies or the
conditions that cause setting conflicts are summarized in Table 3-1.
When programming the waveform type, you also must consider the run mode
as some combinations legal waveform types may cause conflicts with run
mode types. For example, arbitrary and sequenced waveforms may not
conflict in continuous run mode but if run mode is changed to burst, an error
will occur. The conditions that will cause the run mode to generate a settings
conflict errors are summarized in Table 3-1 as well.
There are three function calls that are available for programming the output
type. The most important points before you start writing your programming
routines is to decide if both channels will be programmed to output two
different output types or if they will share the same output type and run
modes. Here are the three options:
1. The
ri3156b_set_global_operating_mode ()
- has five variables: Channel
1 waveform, Channel 2 waveform, Carrier Run Mode and Operate
Enable Source. This function call is the best to use if channels need to be
programmed with different functionality
2. The
ri3156b_set_common_waveform_mode ()
- has only one variable
that sets both channels simultaneously to the same waveform mode. This
function call would be the best to use if channels need to be programmed
with the same functionality.
3. The
ri3156b_set_common_waveform_mode ()
- allows separate
programming of each channel to a different waveform mode. From all
functions, this is the least recommended function to be used as it may
cause setting conflict errors should one not fully understand the limitation
of the product. For example, the default waveform mode is Standard. If
you use this function call to change the waveform mode to arbitrary, the
3156B will immediately generate an error because it has only one sample
clock source while Standard and Arbitrary waveforms use two different
sample clock settings and therefore, this call will generate an error. The
Set Active Channel command is required to program each channel
separately.
The WaveCAD Main Panel can be used for selecting the output type. Note
however, that WaveCAD is using the function call
ri3156b_set_common_waveform_mode ()
to set up both channel
simultaneously so if you need to set up the 3156B to output different
waveform types from each channel, the only way to use WaveCAD is from its
function call editor, as explained in Chapter 4.