User Manual

123B/124B/125B
Users Manual
42
Zooming Harmonics
If the harmonics bars screen is shown, you can zoom
vertically for a more detailed view. Use
YZ to zoom in
or zoom out.
The scale at the left side changes when zooming in or
out.
Fieldbus Mode
Fieldbuses are bi-directional, digital, serial control
networks used in process control and industrial
automation.
The Test Tool can indicate the status of the following
aspects of the OSI model Physical Layer:
• Voltage levels (bias, high level, low level)
• Bit width – baud rate
• Rise and fall time
• Distortion
The Test Tool can show the bus signal waveform in the
Eye-pattern mode, see page 47.
The Test Tool operates in full automatic (ranging and
triggering) mode. Test limits are preset, but can be
changed, see page 47.
For supported bus types and protocols see Table 9.
For extended information on Fieldbuses and fieldbus
measurement, see Appendix A of this manual.
Note
To check a suspected cable you can make
resistance measurements and capacitance
measurements using the Scope/Meter mode.
To do fieldbus measurements:
1. Push  to open the MENU.
2. Use YZ to highlight BUSHEALTH.
3. Push  to open the BUS HEALTH menu.
4. Use
YZ to highlight the bus type.
Select User1 or User2 to create a customized set of
limits to test nonstandard bus systems. See page 48
for information about how to set the test limits.
Default settings are RS232 for User1 and Foundation
Fieldbus H1 for User2.
5. Push  to make the change.
For bus types with additional options, a secondary
menu is available. Use
YZ to highlight the option
and  to make the change.
An example of the screen is shown in Table 10.
6. Connect the inputs as shown in Figure 8, setup 4.