Thank you for attending FieldComm Group’s webinar. Here are some of the questions from our members who attended. If you have further questions, please visit the Member Support Portal at for additional FDI development resources.

The webinar recording FDI Device Package Development - Upload/Download and Offline Configuration is available at this link on our YouTube channel: FCG-TV 2021 Webinar Series - YouTube

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FDI Device Package Developer Q&A 

FDI Device Package Developer Q&A 

Q: We have some parameters that are password protected.  You must enter a password through the device's local user interface or through HART.  The password is a write-only variable.  Currently, to satisfy the UL/DL requirements a workaround to skip these are used if PW is 0 or null.  Will there be an interactive DL/UL in the future?

An Interactive download menu has been added to the FDI specifications (Edition 1.3). 

Q: When downloading a Bit Enumerated Parameter to the Device, do we expect Hosts to read the Device's Bit values first (then merge it to our offline Bit value) before applying the offline Bit values to the Device? or should we expect hosts to replace the Bit parameters to the device?

The offline data set will be written to the device during the download. The data available prior to starting the download could be from an upload from the device, edited values via the offline_root_menu, or a combination of these inputs. A bit enumerated variable is treated same in offline as for online.  If a user makes edits to a bit-enum value in an offline session, the offline data set will maintain the state of each individual bit within the whole value, and write the whole offline value (set of all bit enums) as one to the device.  If there is any merging of bit values necessary for some special reason, this would need to be done programmatically in the EDD.

Q: Is it possible to clone 2 devices of the same family using the Upload and Download Menu Parameters?   

Using bulk download, it is possible to apply the same configuration to multiple instances of the same device type and revision, using an appropriate EDD or FDI Device Package for those instruments.

Q: Is it possible to see the offline and online parameters of the device for comparison? 

Yes, using the FDI RRTE (Reference Runtime Environment) a developer can update an offline parameter, perform the download to the device, then switch to the appropriate online menu to see the online parameter value changed due to the download.

Q: Should we use Actions on Menus or Variables? 

Yes. You can include PRE/POST READ/WRITE Actions on download variables or download menus, however, they cannot contain user interactions for a non-interactive download.  Actions on the upload/download menus are strictly called during the transfer process. There are other differences and the EDD writer should review EDD Interpretation Specification [FCG TS61804-4, Ed 2.0, chapter at]

Q: Please clarify how the order of the menu affects the order of parameter writing?  

See the EDD Interpretation Specification [FCG TS61804-4, Ed 2.0, chapter at]. The order of the items to be written shall be determined according to the download menu. VARIABLEs, LISTs, RECORDs, or value arrays should be written to the device in the order in which they appear in the download menu. If the item is a MENU, the sub-menu should be processed in the same way as the download menu.   

Q: Is it necessary to have all the variables defined in the upload and download menus also appear in the offline_root_menu? 

Yes, this is recommended so that the user can inspect the data being transferred to and from the device.  The upload and download menus do not generate a user interface. The offline_root_menu provides UI for the end-user to review and change values in the offline data set which will be transferred to the device.

Q: Is Validity applicable to the upload or download menus? 

The Validity attribute only applies to the offline_root_menu. The upload and download menus are not visible to the user.  See the EDD Interpretation Specification [FCG TS61804-4, Ed 2.0, chapter at ] for further details.

Q: Can you rename the upload and download menus? 

No. The standardized menus have specific names so that the Tokenizers recognize them and appropriately assign symbol IDs. 

Q: What strategy we should follow while designing the offline menu? What kind of variables can be excluded while designing an offline menu? 

The Offline root menu, and consequently the upload and download menus, are meant for commissioning or configuring the device. You can exclude dynamic process variables as they do not typically influence the device configuration. Variables that are only meaningful to configure for an online device can also be excluded.  For example, variables related to input or output calibrations (trims) may be excluded from the offline (and upload/download) menus if their values cannot be determined in an offline configuration. You need to have a physical device to perform calibrations.