- 2079 Baisakh · 2+6 marks
MBI features; open vs closed loop compared
Short answer
Features: programmable, intelligent decision, high accuracy, multi-channel, data storage and communication, self-test. Open loop has no feedback, is simpler, cheaper, always stable (e.g., washing machine, traffic light). Closed loop uses feedback for error correction, higher accuracy (e.g., furnace temperature control).
What are the basic features of MBI system? Compare open loop and closed loop microprocessor based system with suitable examples.
Basic features of an MBI system
- Programmable and flexible: functions change by software.
- Intelligence: decision making, limit checks, alarms, linearisation.
- High accuracy, stability and repeatability; software calibration.
- Multi-channel handling by multiplexing.
- Data storage, display, printing and communication links.
- Self-test and diagnosis; low cost, size and power.
Open loop vs closed loop microprocessor systems
Open: Set -> [uP] -> [DAC/Driver] -> [Actuator] -> Process
Closed: Set ->(+)-> [uP] -> [DAC] -> [Actuator] -> Process
^- |
+---- [ADC] <- [Conditioner] <- [Sensor]-+
| Point | Open loop | Closed loop |
|---|---|---|
| Feedback | Absent | Present |
| Sensor and ADC | Not needed | Needed |
| Accuracy | Depends on calibration | High |
| Disturbance | Not corrected | Corrected |
| Cost, complexity | Low | Higher |
| Stability | Always stable | Needs tuning |
| Example | Automatic washing machine cycle, traffic light, stepper motor positioning | Room or oven temperature controller, motor speed control, liquid level control |
✓ Answer checked by Claude Sonnet 5.5
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