NI Configurator- Multi-DD versions of same device gets confused

[craiglar]

Has anyone else seen that if you have multiple DD versions of the same Device Type on the same FF segment, NIFBUS and NI Configurator cannot keep them straight?  It appears to load only the DD for the first device it encounters on the network, and then tries to use that DD for all other devices.

This will cause DD Mismatch Errors in the subsequent devices.

I need a fix, or workaround for this problem for a customer in South Africa.

[fieldbus]

When you talked about "multiple DD versions of the same Device Type", do you mean the DD files have the same Device Revision but have different DD Revision like 0301.ffo/0301.sym and 0302.ffo/0302.sym?

If yes, then I'd like to quote FF policy document FF-625 (Rev 1.0) "DD/CF Revision Policy", which states "The DD_REV parameter shall specify the minimum DD Revision (bb) that should be used for a device" and "This value may be greater than that found in the Resource Block if this DD has been revised".

According to this document,  the host is recommended to chose the highest values of DD_REVISION; in this case, Configurator would choose 0302.ffo/0302.sym even the DD_REVISION of the device is 01 (DD 0301). Because the DD files in higher revision are supposed to be backward compatible, so the newer DD files should work well with the device with older DD_REVISION.

If your problem is not the case, then probably the Configurator has some problems, please provide further information about the errors. Thanks.

[craiglar]

In the above problem, the DDs are both registered, and ITK certified.  The older version DD is 0502.ffo. The newest DD is 0601.ffo.  This should fully comply wiht the FF requirements.

[craiglar]

I have discovered a workaround that seems to at least get the job done.

The problem is somehow related to the device address.  NI Configurator is only using the DD of the first device version it encounters.  It then tries to apply the same DD to the other version devices.

The workaround is to swap the address of the devices each time you need to work on them.  Move one of the desired version device's address to be lower than the other version, stop and restart NI Configurator.  It will now read the correct DD for the 'new' lowest address device and let you work with those version devices.  To work on the other version, you swap the address again, restart NI Configurator, and work on those devices.

Tedious, but it appears to let you get the job done.  This information has been passed on to NI support to help them track down the cause of the behavior.

[fieldbus]

It turns out to be a bug of Configurator. As a fact, it only occured between 0601 DD and 0502 DD; but there is no problem between 0601 DD and 0501 DD. 

To be more specific, the problem only happens if the sums of DEV_REV and DD_REV of the two DD files are the same, for example: the sums of 0601 DD and 0502 DD are the same (7), then there will be a problem if you use both of them; but the sums of 0601 DD and 0501 DD are different (7 and 6), thus there is no problem if you use 0601 and 0501 devices together.

NI has accepted this bug and will release the fix in the next version (Configurator v3.2).

Thanks for the workaround although it is tedious as you said. Good news is that this bug does not affect most of FF instruments or their DDs.