The correct answer is: A. has a reliable long life compared to relay logic.
A PC in industrial control has a number of advantages over relay logic, including:
- Reliability: PCs are much more reliable than relay logic. Relays are mechanical devices that can wear out over time, while PCs are electronic devices that are much more durable.
- Long life: PCs have a much longer life than relay logic. Relays typically have a lifespan of 10-15 years, while PCs can last for 20 years or more.
- Flexibility: PCs are much more flexible than relay logic. Relay logic is a fixed system that cannot be easily changed, while PCs can be easily programmed to change their function.
- Cost: PCs are much more cost-effective than relay logic. The initial cost of a PC is higher than the cost of relay logic, but the long-term cost of ownership is much lower.
- Ease of use: PCs are much easier to use than relay logic. Relay logic requires specialized training to operate, while PCs can be used by anyone with basic computer skills.
B. is very difficult for the inexperienced programmer to understand is not an advantage of a PC in industrial control. PCs can be difficult to program, but this is not necessarily an advantage. In fact, it can be a disadvantage if the programmer does not have the necessary skills.
C. is unreliable because there are no moving parts is not an advantage of a PC in industrial control. PCs are reliable, but they are not immune to failure. In fact, PCs are more likely to fail than relay logic because they have more components.
D. All of the above is not the correct answer. Only option A is an advantage of a PC in industrial control.