Performance problems, Missing link – National Instruments NI-FBUS User Manual

Page 120

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Appendix B

Troubleshooting and Common Questions

© National Instruments Corporation

B-11

NI-FBUS Configurator User Manual

problem because it takes the device less time to be recognized at the new
address.

For testing purposes, setting the

NumOfUnpolledNodes

to zero ensures

that all addresses will be checked. Once the device is found, you will
probably want to advise the

NumOfUnpolledNodes

and/or

FirstUnpolledNode

to avoid the performance slowdown discussed

above.

Performance Problems

The control is slow.

The macrocycle time might be too long. Edit the function block schedule
and decrease the macrocycle time. For more information about editing the
schedule, refer to the

View and Edit a Schedule

section of Chapter 2,

Using the NI-FBUS Configurator

.

Missing Link

Your interface(s) does not appear in the Add Links dialog box.

You may need to upgrade your software key to support the additional links.
If you purchased additional licenses to access more than the default number
of links, contact National Instruments to obtain a new software key.

A device believed to be a link master does not show up in the network
parameters window.

For a link master device to receive the schedule, it must be configured to
receive it. This setting is made by double-clicking Network Parameters in
the configuration tree and ensuring that the checkboxes for the appropriate
link master devices are checked. If a device does not appear in this list,
complete the following steps:

1.

Right-click the interface in the configuration tree and select Advanced
View
. The MIB parameters appear underneath the interface board.

2.

Double-click the MIB to bring up another window. Look at the
parameter called

BOOT_OPERAT_FUNCTIONAL_CLASS

. The value

2

indicates that the device identifies itself as a link master. If this
parameter does not equal

2

, the device is not identifying itself as a link

master. Contact your device manufacturer.

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