
Chapter 6
VXI-MXI-2/B Configuration and Installation
©
National Instruments Corporation
6-9
MXI-2 Configuration Reference Manual
If you change the S1 setting to drive CLK10 out the MXIbus, do not set the
W1 jumper setting to receive the MXIbus CLK10. Instead, use the settings
shown in Figure 6-4a or 6-4b as appropriate.
Caution
Do not configure more than one MXIbus device to drive the MXIbus CLK10.
Having a second device driving MXIbus CLK10 could damage the device.
Figure 6-6 shows the configuration settings for receiving and driving
MXIbus CLK10, respectively.
Figure 6-6.
Receiving or Driving MXIbus CLK10
Trigger Input Termination
You can use switch S5 to terminate the external trigger input SMB with
50
Ω
. Figure 6-7a shows the default setting for a nonterminated trigger
input SMB. Use the setting of Figure 6-7b to terminate the trigger
input SMB.
Figure 6-7.
SMB Trigger Input Termination
MXIbus Termination
The first and last MXIbus devices connected to the MXIbus—whether
using a single MXI-2 cable or daisy-chained MXI-2 cables—must
terminate the MXIbus. Any MXIbus devices in the middle of a MXIbus
daisy chain must
not
terminate the MXIbus.
The VXI-MXI-2/B automatically senses whether it is at either end of the
MXIbus cable to terminate the MXIbus. You can manually control MXIbus
termination by defeating the automatic circuitry. Use switches 3 and 4 of
a. Receive CLK10 from
MXIbus (Default)
MBCLK10
IN
OUT
S1
b. Drive MXIbus CLK10 from
VXIbus CLK10
MBCLK10
IN
OUT
S1
a. Non-Terminated External Trigger
Input SMB (Default)
b. Terminated External Trigger
Input SMB with 50
Ω
TERM
TRIGIN
S5
TERM
TRIGIN
S5
( = NO)
( = NO)