Module Management

A module is one configured instance of the application. It owns the matching operation, with its own settings and results:

hdvisionsystems/lumiscan-object-finder/<module-id>/find-object/...

Creating a template is not per module: it writes into the one directory every module shares, so it lives on the system node as system/create-object. See Creating an Object.

Modules can be created and removed while the application runs. A fresh installation serves one module, named module-1.

On ctrlX OS, one licence covers ten modules. The eleventh module acquires a second licence of the same key, and a module is refused with status -11 when no licence on the device covers it.

The management node sits outside the modules:

hdvisionsystems/lumiscan-object-finder/system/

Nodes

Node Type Description

modules

string array

The modules that currently exist

create-object/execute

method

Cut a template out of a live image and save it into object-dir, for every module to use. See Creating an Object

create-module/execute

method

Create a module and its node subtree

create-module/input/module-id

string

Name of the module to create. Lower case letters, digits, - and _ only; must not be system and must not already exist

remove-module/execute

method

Remove a module and its node subtree

remove-module/input/module-id

string

Name of the module to remove

save-current-modules/execute

method

Persist the module list, so the same modules are recreated on the next start

save-module-inputs/execute

method

Persist one module’s settings

save-module-inputs/input/module-id

string

Name of the module whose settings to save

Every method also has output/status-code and output/status-text.

Creating a module

  1. Set system/create-module/input/module-id to the new name

  2. Write to system/create-module/execute

  3. Check system/create-module/output/status-code is 1

The module is live at once, with default settings, and appears in system/modules. It is not permanent until the module list is saved.

Removing a module is the mirror image, through remove-module. A module is refused with -1 (busy) while one of its own operations is running, rather than having its nodes destroyed mid-execution.

A module created now is a new module: it starts with the default input values, even if a module of that name existed before and its settings were saved. Those settings stay on disk until the removal is made permanent - save-current-modules deletes the saved inputs of every module the new list no longer names, because until the list is written a removal is not permanent and a restart brings the module back with its settings intact.

Saving

Two things are saved separately, and both must be saved to survive a restart:

  • the module list - save-current-modules, so the same modules are recreated;

  • each module’s settings - save-module-inputs, once per module.

To save a module’s settings:

  1. Set system/save-module-inputs/input/module-id

  2. Write to system/save-module-inputs/execute

  3. Check system/save-module-inputs/output/status-code is 1

Every input of that module is written to the application configuration directory and restored on the next start. Results are not saved - they are produced by the next run. A module’s image stream settings are saved in the same file, by the stream’s own methods - see Kept in the settings file.

A setting whose node no longer exists after a software update is skipped with a log entry, so an older configuration never prevents the application from starting.

Why the address contains a module even with one module

The <module-id> level is always present, so addresses do not change when a second module is added: a program written today against module-1 keeps working. It also matches the path convention the other LumiScan applications document, see Addresses and Modules. How the finders' modules differ from those of the Cam Driver, AI Object Matching and Calibration is summarised in Settings, Modules and Restart.

What is shared between modules

Modules are independent in everything except templates. system/object-dir names one directory for the whole application, system/create-object writes into it, and every module searches it, so a template only ever has to be created once. See Object Storage.