National Instruments NI-FBUS User Manual

Page 116

Appendix B

Troubleshooting and Common Questions

B-7

NI-FBUS Configurator User Manual

I have assigned an address to my device, but the NI-FBUS
Configurator is not seeing the device. Why?

In the NI-FBUS Interface Configuration utility, there is an advanced
parameter called

First

Unpolled

Node

. After the node is specified

by this parameter, the NI-FBUS Configurator will not poll the subsequent
N nodes, where N is the

NumUnpolledNodes

. Make sure that your device

address is being polled. The default is 0x25.

The second possibility is that the timing parameters (T1, T2, T3) are
improperly set. The default for these are 0x40000, 0x40000, and 0x30000,
respectively. Other settings to try are 0x60000, 0x60000, and 0x35000.
If these parameters are set inappropriately, an identify message can go out
before the device is at its address, resulting in the device missing its chance
to identify itself. This problem causes the Set Address sequence to fail. This
problem has in particular been seen with the Fisher Rosemount
3244MS rev3.

How can I get a slow device onto the bus?

There are timing parameters (MIB parameters) that can be set for the link,
including the minimum interPDU delay, the maximum response time, and
the slot time. This allows you to accommodate devices with slower
response times.

I am getting an error

DD_SIZE_MISMATCH_ERROR

The device description file installed in your machine does not match the
device.

Open the resource block for the mismatched device.

Check the

MANUFAC_ID

DEV_TYPE

DEV_REV

, and

DD_REV

Open the NI-FBUS Interface Configuration utility and click the
DD Info button.

Find the

.ffo

file in the base directory for the device description.

Compare the

.ffo

revision number with the manufacturer ID, device

type, device revision, and device description revision from the resource
block. If the revisions are different, import the device description file
for the correct revision of the device. If they are the same revision,
contact the device vendor to get correct device description files.