^HL / ~HL - Return RFID Data Log to Host
Returns the printer's log of RFID read and write operations to the host.
An RFID printer writes a record of each tag operation into RAM. ^HL requests
that log, clears it, and starts a new one. The read is destructive, so two hosts
that poll the same printer each get only part of the history. Nothing from this
command reaches the printed image.
Syntax
^HLAlso accepted with the other prefix: ~HL.
Support
Accepted and skipped, because it configures the printer rather than the label. It cannot change the rendered output, and Labelary skips it too.
Returns a log held in printer RAM over the host channel. This service has no printer, no log and no host channel, and nothing about it reaches the label image. The renderer does not parse this command. It reports IGNORED_COMMAND at info severity, which does not reach X-Warnings. Labelary is also silent, so the rendered label is identical in both engines and with or without the command. — not pinned by a test
Labelary renders this command.
Parameters
^HL / ~HL takes no arguments.
Behavior
Each logged operation is one line with the form C,EEEE,DDDD…: the operation, the
RFID error code, and the data read or written. The operation is R for a read,
W for a write, and L for a lock. The data uses the format of the ^RF command
behind it, which is ASCII, hexadecimal, or EPC. The log is therefore readable only
together with that format.
Two conditions lose the log. The printer clears it automatically above 64 KB,
approximately 2000 operations, and writes the line Logfile automatically reset
in place of the history. The log also sits in RAM, and a power cycle discards it.
Retrieve it frequently.
Both prefixes name the same command. ~HL acts when the printer reads it, which
is the usual reason to use it in a queue of formats.
Example
The log request sits outside the label format, and the label prints as though it were not there:
~HL
^XA
^FO50,50^A0N,30,30^FDPallet 4472^FS
^XZ
Related commands
^HRCalibrate RFID Tag PositionRuns RFID tag calibration and returns the resulting position and power table to the host.^RFRead or Write RFID FormatReads a tag, encodes a tag, or declares the access password used by later lock commands.^RWSet RF Power Levels for Read and WriteSets the radio power used for reading and writing tags, and picks the antenna element.^HHConfiguration Label ReturnSends the printer's configuration back to the host as text.