Serial Communications
3-3
690+ Series Frequency Inverter
File Read (FR)
Reading a file is achieved using the FR mnemonic. The FR write command is used to specify
the name of the file to read. For example, to read the Configuration file “APPLICATION” from
a drive at address 00 (note the address is always entered twice, so if the address is 01 you enter
0011):
Request:
0 0 0 0 [STX] F R [FS] 0 [GS] [GS]‘ A P P L I C A T I O N . C F G [ETX] [BCC]
On receiving this command the drive will read the specified file from the file-store into a RAM
buffer. If the file is protected or is not found then the drive will reply with a NAK.
Request:
The FR read command is then used to read the file from the RAM buffer:
0 0 0 0 F R [ENQ]
[ENQ]
is the enquiry character, 0x05
Response:
A: [STX] F R [FS] 0 [GS] [GS] file_name [RS] file length [RS] protected flag [EXT] [BCC]
B: [STX] F R [FS] 1 [GS] block_number [RS] block_data [EXT] [BCC]
C: [STX] F R [FS] –1 [EXT] [BCC]
Response A
is returned following the first FR read command after a FR write. It has an action of
0 indicating that this is the start of the read process. This reply contains the file name, the file
length and the file protected flag.
Response B
is returned while data is being transferred.
Response C
is returned once all data has been transferred. This has an action of –1 indicating
that file transfer has finished.
Should the receiving equipment notice a communications failure, such as a missing block, a
transfer may be restarted using the FR write command. The FR write command may contain a
block number if you want to restart the transfer from a block other than 0.
File Write (FW)
The file write command FW is used to write file data to the drive. This mirrors the use of the FR
command. The format of the message is:
Request:
A: 0000 [STX] F W [FS] 0 [GS] [GS] name [RS] length [RS] protected [EXT] [BCC]
B: 0000 [STX] F W [FS] 1 [GS] block_number [RS] block_data [EXT] [BCC]
C: 0000 [STX] F W [FS] –1 [EXT] [BCC]
Request A
is used to initiate a write. This has an action of 0 and contains the file name, the file
length and the file protected flag.
Request B
is used to transfer the file data in blocks of up to 64 ascii hex characters.
Request C
is used to indicate that the file transfer is complete and that the file should be
committed to non-volatile data. On receiving this request the drive validates the contents of the
file data. The data is expected to be in the same format as that returned by the FR command.
This includes a checksum that is used by this validation process. If the file data is valid then it is
written to the file store. As part of this process, the file store automatically creates a backup of
any existing configuration of the same name as that being written. This backup copy will be
used if the file save fails.
