~HD - Head Diagnostic
Sends a power-supply and head-temperature report back to the host.
~HD returns the printer's power-supply and printhead temperature figures over the
link, for a terminal emulator. It is a diagnostic aid for an operator at a console,
not something a label format needs: the reply goes to the host, never onto the
media.
Syntax
~HDSupport
Accepted and skipped, because it configures the printer rather than the label. It cannot change the rendered output, and Labelary skips it too.
Returns power-supply and head-temperature figures over the printer's link. This service has no printhead, and nothing it could report changes the label. 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. — not pinned by a test
Labelary renders this command.
Parameters
~HD takes no arguments.
Behavior
The guide gives no reply layout, only that the printer returns status information
about the power supply and the head temperature. The guide specifies the three
strings of ~HS byte by byte, but ~HD answers a person rather than a parser.
A render request has no printhead and no terminal. The renderer ignores the command,
and the page is unchanged. It reports IGNORED_COMMAND at info severity, which does
not reach X-Warnings. Labelary is also silent. On real hardware ~HQ JT and
~HQ PH are the modern printhead reports, and neither has a counterpart here.
Example
The command is inert, so the label is whatever the rest of the format draws.
^XA
~HD
^FO50,50^A0N,40,40^FDHead diagnostic^FS
^XZ
Related commands
~HSHost Status ReturnSends three status strings describing the printer's current state back to the host.~HQHost QuerySends one of ten named printer reports back to the host.~JNHead Test FatalTurns the printhead element test on, so that a failed element halts the printer.