A distributed output should never depend on an undefined network condition. Titania provides configurable communications watchdog behaviour, per-channel power-up values and per-channel communications-loss safe values so the machine response can be engineered and tested.
Determine the correct state
The safest electrical state is not always OFF. A valve may need to close, open or hold; an alarm may need to energise; a brake may require power. Determine the required response through process, machine and functional-safety assessment before configuration.
Set watchdog timing
Choose a watchdog interval longer than normal communication jitter but short enough to meet the operational response requirement. Include gateway, PLC scan, network retry and maintenance-mode behaviour in the calculation.
Test failure scenarios
- Disconnect the RS-485 line and confirm the safe value.
- Stop the master application and verify watchdog expiry.
- Cycle field power and confirm the configured power-up state.
- Restore communication and verify controlled recovery without output chatter.
- Read output-command and driver-fault status during each test.
Document responsibility
Record the owner of each safe-state decision, the approved output value, watchdog time, recovery rule and test result. Changes should be controlled because they alter machine failure behaviour.
Technical basis: Titania Modbus DI-8 DO-8 datasheet TTN-DS-2026-001, issued 19 July 2026. Confirm the current hardware, firmware and controlled document revision before implementation.
