Ten Daily Electronic Common Sense-Section 87

What are the two main ways to measure temperature in the clinic?

There are two main ways to measure temperature in clinical practice: contact and non-contact.
The former mainly places sensors such as thermistors and thermocouples on the target site. The purpose of direct temperature measurement is achieved by the use of heat conduction.
The latter mainly uses pyroelectric sensors. The purpose of indirect temperature measurement is achieved by the received heat (infrared rays) radiated from the measured part.

What is the suspension system usually composed of?

Elastic elements, damping elements and guiding elements.

What are the external terminal parts of the PLC and what is the function?

External terminals include PLC power terminals (L, N, 〨), DC 24V power terminals (24, COM) for external sensors, input terminals (X), output terminals (Y), etc.
The external terminal mainly completes the connection of input/output (ie I/O) signals. It is a bridge between PLC and external devices (input devices, output devices).

What are the common sensor interface circuits?

Impedance matcher, bridge circuit, amplifier circuit, switching output circuit, analog output circuit, digital output circuit, serial output circuit.

What are the characteristics of a single sensor node?

Concurrency is dense and modularity is high.

What are the precautions for using the circuit block connection instructions in the PLC?

1. ORB is a parallel connection command for series circuit blocks, and ANB is a series connection command for parallel circuit blocks. None of them have operating elements and can be reused many times.
2. The ORB instruction is to connect the series circuit block in parallel with the previous circuit, which is equivalent to a vertical connection on the right side of the circuit block. The initial contact of the series circuit block should use the LD or LDI instruction. After completing the internal connection of the circuit block, use the ORB instruction to connect it in parallel with the previous circuit.
3. The ANB instruction is to connect the parallel circuit block in series with the previous circuit, which is equivalent to the series connection between the two circuits. The starting contact of the parallel circuit block should use the ID or LDI instruction. After completing the internal connection of the circuit block, use the ANB instruction to connect it in series with the previous circuit.
4. ORB and ANB instructions can be used repeatedly, but when using ORB continuously, it should be limited to less than 8 times.

How to classify ARM instructions?

ARM’s fixed-point instruction set and ARM’s floating-point instruction set.

What is the construction and electrical characteristics of the transformer?

The structure of the transformer is relatively simple, mainly composed of an iron core and a wire.
The coil, also known as the winding, is wound on the iron core and transmits the alternating magnetic flux it generates through the iron core.
Coils are divided into primary coils and secondary coils. The primary coil is also called the primary coil or primary winding. The secondary coil is also called the secondary coil or secondary winding. The coil connected to the power supply (or signal source) is called the primary coil. The coil connected to the load is called the secondary coil.  
The iron core is formed by laminating many silicon steel sheets. The silicon steel sheets are insulated from each other in order to reduce the eddy current loss caused by the alternating magnetic field on the iron core.

What are the precautions for using the MEP/MEF pulse calculation instruction?

1. The (L)MEP(MEF) instruction will output pulses at the rising (falling) edge of the operation result without this instruction.
2. The MEP (MEF) instruction cannot be directly connected to the bus, and its position in the ladder diagram is the same as that of the AND instruction.

What is the piezoelectric effect?

Usually, some substances are mechanically deformed by an external force in a certain direction. A polarization phenomenon occurs inside, and at the same time an electric charge is generated on its surface.
When the external force is removed, these substances return to their uncharged state. This phenomenon of converting mechanical energy into electrical energy is called the piezoelectric effect.