The correct answer is: A. all of the logic status is maintained in memory.
A programmable controller (PLC) is a solid-state electronic device that uses a programmable processor to control various types of machinery. PLCs are used in a wide variety of industries, including manufacturing, process control, and building automation.
One of the key features of a PLC is that it maintains all of the logic status in memory. This means that the PLC can be programmed to perform complex logic operations, and the results of those operations will be stored in memory. This makes PLCs very versatile and powerful devices.
Option B is incorrect because latched data can be stored in memory without the need for an external latching relay. Option C is incorrect because PLCs can perform a variety of mathematical operations. Option D is incorrect because not all of the above statements are true. Option E is incorrect because the correct answer is A.
Here is a more detailed explanation of each option:
- Option A: All of the logic status is maintained in memory. This is a key feature of PLCs, and it allows them to perform complex logic operations.
- Option B: Any latched data must be done using an external latching relay. This is not true. Latched data can be stored in memory without the need for an external latching relay.
- Option C: Mathematics cannot be performed. This is not true. PLCs can perform a variety of mathematical operations.
- Option D: All of the above. This is not true, because option B is incorrect.
- Option E: None of the above. This is not true, because option A is correct.