ci-server-engineer/.claude/skills/class-object-engineering/tasks/traditional-class.md

task	version	source	status
Write a Traditional class with prompts, signals built from the object name, and items created from a template	R1.05 (first written for R1.03)	IM 36K10P10-01EN 4th ed. (Feb. 2026) §1–§5, §8, §10, §11.2.8 (only contact information changed since R1.03); IM 36K10L10-01EN; practiced with CI-Eng-Sample class CIENG_TANK 2026-09-30	verified on R1.03 (2026-09-30); re-tested on R1.05 2026-10-08 (CIENG_TANK compiled on load, TANK1.CALC.VOLUME created, level 50 gave volume 100, object removed with its items). Refused object, PRINT with %%, and the runtime attribute change (§3) were not re-tested on R1.05

Traditional class: prompts, signals, created items

Worked example: class CIENG_TANK and object CI-Eng-Sample.TANK1.CALC (examples/CI-Eng-Sample/06_class_df.qli, 07_object_df.qli). Loading and removing: task load-class-object.md. Language reference: knowledge/manuals/IM36K10P10-01EN.md.

1. Design

One class = one kind of equipment; one object per piece of equipment. Put the variable parts (which items, which settings) in the class prolog so they are fixed when each object is created:

Need	Use
Setting per object, asked at creation	ATTRIBUTE x OBJECT FLOAT; + PROMPT x QUERY "…"; → ATTR_VALUE_n in OBJECT_DF
Setting shared by all objects	ATTRIBUTE x CLASS …;
Existing item next to the object	`SIGNAL s := SECTION
New item per object	SIGNAL s := FROM "<template item>" MAKE "FIELD" EQUAL value …;
Refuse bad input	IF … THEN ERROR "text"; ENDIF; in the class prolog
Periodic run	trigger group on the class (TRIGGER_1) or object
Run on a change	TRIGGER VALUE (or STATUS, UPDATE …) on the signal

Template items: keep them in their own section (sample: CI-Eng-Sample.TEMPLATES.TPL_REAL) and load them before the class.

2. Example

CLASS CIENG_TANK;
  PROLOG
    ATTRIBUTE CAPACITY OBJECT FLOAT;
    PROMPT CAPACITY QUERY "Tank capacity (m3)";
    SIGNAL LEVEL := SECTION || ".LEVEL" TRIGGER VALUE;
    SIGNAL VOLUME := FROM "CI-Eng-Sample.TEMPLATES.TPL_REAL" MAKE
      "DESCRIPTION" EQUAL "Tank volume (m3), class CIENG_TANK";
    IF CAPACITY <= 0 THEN
      ERROR "CIENG_TANK: capacity must be > 0";
    ENDIF;
  BODY
    METHOD CALC;
      BODY
        VOLUME := LEVEL * CAPACITY / 100.0;
        IF LEVEL >=: 80.0 THEN
          PRINT "CIENG_TANK ", SECTION, ": level reached 80 pct, volume ", VOLUME;
        ENDIF;
    ENDMETHOD CALC;
ENDCLASS CIENG_TANK;

Object CI-Eng-Sample.TANK1.CALC with ATTR_VALUE_1 = "200":

• SECTION = CI-Eng-Sample.TANK1, so LEVEL → CI-Eng-Sample.TANK1.LEVEL.
• VOLUME has no "NAME", so the item is CI-Eng-Sample.TANK1.CALC.VOLUME; the section TANK1.CALC is created too. Both are deleted with the object.
• LEVEL 50 → VOLUME 100; 82 → 164.
• >=: prints once when the level crosses 80 (message in umhlog.log, sender OPCEXE1).

Rules learned on the test system:

• A single % in PRINT text cuts the message at that point; write %% for a literal percent sign (verified; \% does not work, ISS-025).
• An object at root level has an empty SECTION; build names with an IF then (release notes).
• Item names in SIGNAL strings must match exactly; an item that does not exist makes the object creation fail.

3. Check and operate

• Signals → items: export OBJECT_SIGNAL_DF with filter 'OBJECT = "<object>"' (sample: …CALC:LEVEL → CI-Eng-Sample.TANK1.LEVEL, …CALC:VOLUME → …CALC.VOLUME).
• Attribute values: export OBJECT_ATTR_VAL (same filter); record name <object>:<attribute>, field ATTR_VALUE.
• Change an attribute of a running object (verified): dssqld -m on OBJECT_ATTR_VAL:

  @FIELDS
  NAME,ATTR_VALUE
  
  @OBJECT_ATTR_VAL
  "CI-Eng-Sample.TANK1.CALC:CAPACITY","400"
  

  The new value is used from the next run (level 50 → volume 200). Do not change attributes that were used to build signal names: the signal keeps its old item (P10 §8.3).
• Class-wide attributes: CLASS_ATTR_VAL (<class>:<attribute>), not practiced.
• Refused object: loading ATTR_VALUE_1 = "0" gave Errors 1 with OPC-E-INFO, CIENG_TANK: capacity must be > 0 in the .qlo; nothing was created.

Changing the class source later: task change-reset-class.md.