Application file packets

Applicable receivers:  All receivers

To send application files to the receiver, upload the files via the web interface, or create the application files with a custom software program.

Application files contain a collection of individual records that fully prescribe the operation of the receiver. Application files are transferred using the standard Data Collector Format packet format.

Each application file can be tailored to meet the requirements of separate and unique applications. Up to 12 application files can be stored within the receiver for activation at a later date.

The two important application files in the receiver are:

Name	Function
DEFAULT	Permanently stored application file containing the receiver’s factory default settings. This application file is used when the receiver is reset to the factory default settings.
CURRENT	Holds the current settings of the receiver.

Individual records within an existing application file can be updated using the software tools included with the receiver. For example, the OUTPUT MESSAGES record in an application file can be updated without affecting the parameter settings in other application file records.

Application files can be started immediately and/or the files can be stored for later use.

Once applications files are transferred into memory, command packets can be used to manage the files. Command packets are available for transferring, selecting, and deleting application files.

If any part of the application record data is invalid, then the receiver ignores the entire record. The receiver reads a record using the embedded length. Any extraneous data is ignored. This allows for backward compatibility when the record length is increased to add new functions.

If you are concerned about application files producing the same results on future receivers, make sure that the application records do not contain extraneous data.

Command Packet 64h is sent to create, replace, or report on an application file. The command packet requests the application file by System File Index.

For detailed information about application files and for guidelines about using application files to control remote devices, see Response 64h, APPFILE (Application file record report).

Packet paging

Since an application file contains a maximum of 248 bytes (all records are optional) of data and exceeds the byte limit for RS-232 Serial Interface Specification packets, Command Packet 64h is divided into several subpackets called pages. The PAGE INDEX byte (byte 5) identifies the packet page number and the MAXIMUM PAGE INDEX byte (byte 6) indicates the maximum number of pages in the report.

The first and subsequent pages are filled with a maximum of 248 bytes consisting of 3 bytes of page information and 245 bytes of application file data. The application file data is split wherever the 245 byte boundary falls. Therefore the remote device sending the Command Packet pages must construct the application file using the 248 byte pages before sending the file to the receiver.

To prevent data mismatches, each report packet is assigned a Transmission Block Identifier (byte 4) which gives the report pages a unique identity in the data stream. The software on the remote device can identify the pages associated with the report and reassemble the application file using bytes 4–6.

To save the Command Packet 64h in an application file format, the first two bytes of the file must indicate the length of the command packet in bytes. These bytes are in a little endian format as a UINT16. The bytes of the Command Packet 64h must then follow. All pages of the Command Packet 64h must be included in the file.