Alarms, trips and interlocks
Цель: Изучить тему «Alarms, trips and interlocks» и закрепить её практическими заданиями и самопроверкой.
2 акад. часа чтение и разбор теории, решение задач, работа со схемой или виртуальным стендом и проверка понимания.
Основной материал
Alarm asks operator to act; trip acts automatically. Interlock prevents unsafe command or sequence. Confusing them creates poor safety design.
Example
High temperature alarm warns at 90 °C. HH trip at 100 °C closes feed and opens cooling. Start permissive prevents pump if suction valve closed. These are different functions.
Bypass management
Maintenance may require bypass/inhibit, but uncontrolled bypass defeats protection. Good system records bypass, user, reason, timeout and prominent indication.
Практическая работа
For compressor define one alarm, one shutdown, one start permissive and one maintenance bypass. Explain difference.
Самопроверка
• Alarm vs trip?
• What is permissive?
• What is interlock?
• Why bypass control?
• What information record for bypass?
Что нужно запомнить
- Start permissive prevents pump if suction valve closed.
- Maintenance may require bypass/inhibit, but uncontrolled bypass defeats protection.
- Good system records bypass, user, reason, timeout and prominent indication.
- For compressor define one alarm, one shutdown, one start permissive and one maintenance bypass.