User manual

Chapter 6 System Configuration
VXI-MXI-2 User Manual 6-8 © National Instruments Corporation
2. Determine the number of logical addresses required by the root
device. If the RM is a PC with a MXIbus interface, the total
number of logical addresses required is 1. If the RM is in a VXIbus
mainframe, determine the number of logical addresses required by
all devices in that mainframe. Fill in that number in the appropriate
space in the RM block as shown in Figure 6-7. If you are using the
Base/Size format of the windows, round that number to the next
highest power of two and place that number in the appropriate
space.
Note: If your RM is a PC with a MXIbus interface and you have more than one
VXIbus mainframe on Level 1, you must change the logical addresses of
both VXI-MXI-2 interfaces so that they are not at the default of 1. Select a
logical address that is greater than or equal to the number of logical
addresses required by the mainframe.
In the example system, the multiframe RM is installed in VXIbus
Mainframe #1 and that frame requires 12 logical addresses. We
rounded the value 12 to the next highest power of two and entered
the number 16 into the table.
3. Next, fill in the blanks for the number of logical addresses required
by the first-level MXIbus devices. Using a separate worksheet for
each MXIbus link on Level 1, fill in the blanks for the number of
logical addresses required by the devices on each MXIbus link.
Remember, you do not need to round numbers to the next power of
two if you are using the High/Low format for the windows.
The example system has two MXIbus links on the first level:
MXIbus #1 and MXIbus #2. Figure 6-8 is the worksheet for
MXIbus #1 and Figure 6-9 is the worksheet for MXIbus #2. We
listed the devices on the MXIbus link and entered the number of
logical addresses required by each device into the appropriate
spaces. We then rounded the number of logical addresses up to the
next power of two and entered this number into the table.
4. Fill out a separate worksheet for second-level MXIbus links and
put the results in the appropriate places on the worksheet for the
first-level device to which they are connected. Determine the total
number of logical addresses required for the first-level device by
adding the numbers with “+” next to them. If you are using
Base/Size window formats, round this number to the next highest
power of two and place it in the appropriate space on the
worksheet.