Production Inhibit Timer and Transmission Trigger Timer behavior in Class 0/1 I/O does not fully align with CIP timing semantics

The current Class 0/1 producer timing behavior shows inconsistencies in how application-triggered production, Production Inhibit Time, and periodic transmission triggering interact.
This can cause unexpected produced-frame timing under mixed APP/TTT activity.

Especially the case where the PIT is running and the TTT expires should not trigger message production.

From a product perspective, the core issue is not a single send decision, but the overall timer interaction model:

• Application updates should be rate-limited by Production Inhibit Time.
• Periodic transmission triggering should ensure consumer watchdog continuity.
• Pending data semantics should remain deterministic when updates occur during an active inhibit window.
• Timer behavior should be consistent and predictable under all combinations of APP update, PIT active/expired, and TTT expiry events.

Background:

CIP defines distinct roles for these timing mechanisms:

• Production Inhibit Time provides minimum spacing for application-driven production.
• Transmission Trigger Timer provides periodic trigger behavior to avoid long running silence.
• The combined behavior must remain coherent across edge cases, especially when events overlap in time.

The issue was identified during a timing-model review against CIP Volume 1 and scenario-based event/state analysis.
The implementation needs to be aligned with the intended behavioral model so that produced traffic remains compliant, deterministic, and low-jitter while preserving correct inhibit semantics.