zpl.tools
Media and sensors

^JS - Sensor Select

Chooses between the reflective and transmissive media sensors.

^JS picks which of the printer's two media sensors looks for the label break. The transmissive sensor shines through the stock and sees a gap or web. The reflective sensor bounces light off the back of the liner and sees a black mark. The stock decides which one is correct, so ^JS and ^MN must agree.

Note the prefix. ^JS selects a sensor, and ~JS sets the backfeed sequence. The two commands are unrelated and share a mnemonic.

Syntax

^JSa

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.

This command selects the hardware that tells the printer where the label break is. A render has no sensor and no media. This command is not the same command as ~JS. The command ~JS sets the backfeed sequence. 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

aActive sensoroptional · one of a set

This argument sets which sensor reads the media. The reflective sensor suits black marks on the back of the liner. The transmissive sensor suits gaps and webs.

Default
A on Z-Series printers and R on the S4M
Invalid value
not documented, and we have not measured it. The renderer does not parse this command, and no measurement covers an unrecognized letter.
Test coverage
No documented value is exercised by a test (A, R, T).
A
Auto-select
R
Reflective media sensor
T
Transmissive media sensor

Behavior

The guide restricts the command to Z-Series and S4M printers, and gives their defaults separately: A on the Z-Series, R on the S4M. The guide documents no other printer.

The pair with ^MN is the whole point. Mark-sensing stock, ^MNM, needs the reflective sensor, and web-sensing stock, ^MNW or ^MNY, needs the transmissive one. A leaves the decision to the printer during calibration, which is the safe choice when the stock varies between jobs. ^SS and ^SI then tune the thresholds and LED intensities of the active sensor.

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.

Example

Automatic sensor selection ahead of a label:

^XA
^JSA
^FO50,50^A0N,40,40^FDAuto sensor^FS
^XZ

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