^JT - Head Test Interval

Schedules how often the printhead element test runs, and which elements it covers.

^JT schedules the printhead element test: how many labels apart it runs, and optionally which range of elements it covers. The interval is the point of the command, because the printer runs no automatic test by default and a four-digit count turns it on.

Syntax

^JT####,a,b,c

Support

Recognised, deliberately skippedparsed: none · state: none · rendered: none

Accepted and skipped, because it configures the printer rather than the label. It cannot change the rendered output, and Labelary skips it too.

The command schedules a hardware self-test. 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

####Test intervaloptional · integer

Labels between automatic printhead tests, as a four-digit number. Zero disables the test.

Default: 0000
Accepted range: 0 to 9999 labels
Invalid value: not documented, and we have not measured it. The renderer does not parse or measure this command. The printer ignores a value above 9999. The guide does not state what it uses instead.
Test coverage: No test at the minimum, maximum or one step outside the range.

aManual element rangeoptional · Y or N

Whether the command gives the tested element range explicitly, or the printer chooses it.

Default: N
Invalid value: not documented, and we have not measured it. The renderer does not parse or measure this command. The guide gives N as the power-up value, not a per-command default.
Test coverage: No documented value is exercised by a test (Y, N).

Y: Use the range in the next two arguments
N: Let the printer choose the range (default)

bFirst elementoptional · integer

First printhead element to test, for a manual range.

Default: 0
Accepted range: 0 to 9999
Invalid value: not documented, and we have not measured it. The renderer does not parse or measure this command.
Test coverage: No test at the minimum, maximum or one step outside the range.

cLast elementoptional · integer

Last printhead element to test, for a manual range.

Default: 9999
Accepted range: 0 to 9999
Invalid value: not documented, and we have not measured it. The renderer does not parse or measure this command.
Test coverage: No test at the minimum, maximum or one step outside the range.

Behavior

The guide adds a detail the interval hides: ^JT runs a test on the very next label, unless the count is 0. The command is both a schedule and a trigger.

With a set to N the printer picks the range itself, from the elements it used since the last test. With Y the range comes from b and c, which can cover one area of the label or the whole print width. A last element beyond the configured print width is not an error: the test stops at the print width.

The guide states that the printer ignores an interval above 9999, but does not state what it uses instead.

Example

A test every 100 labels over the full element range, set explicitly:

^XA
^JT0100,Y,0,9999
^FO50,50^A0N,40,40^FDTest every 100^FS
^XZ

Open in viewer

~JN Head Test FatalTurns the printhead element test on, so that a failed element halts the printer.
~JO Head Test Non-FatalTurns the printhead element test back off, so a failed element no longer stops the printer.
^JH Early Warning SettingsConfigures the consumable and maintenance warnings the printer reports as media, ribbon and printhead wear out.