Ten Daily Electronic Common Sense-Section 48

What is a stand-alone CAN controller?

IP Address: This is the IP of the NetFlow collector, and traffic will be sent here.
Port: This is the port used by the NetFlow collector, usually UDP port 2055, but may vary depending on the vendor collecting the data.
Switch IP Address: This configuration can be confusing. In a typical hardware environment, each switch has some kind of IP identity for management. By specifying the IP address here, the NetFlow collector will treat the VDS as a single entity. This IP is not necessarily a valid, routable IP, just as an identifier. For example, “1.1.1.1” is a valid entry.

What are the requirements for metal materials used to make thermal resistance?

1. The resistance temperature coefficient is large, and the resistance keeps a single value with the temperature change and preferably has a linear relationship;
2. The heat capacity is small;
3. The resistivity is as large as possible, so that the size of the component can be made smaller under the same sensitivity;
4. In the working range , Physical and chemical properties are stable;
5. It is easy to obtain relatively pure substances, the materials have good reproducibility and low prices.

What is the main responsibility of EPCglobal?

Adopt global unified standards to establish and maintain EPC networks in various industries. Through the development and management of EPC network standards, the automatic real-time identification of information in each link of the supply chain is ensured, and the efficiency of the logistics supply chain on a global scale is enhanced.

What are the two major categories of optical fiber in the sensor?

• The role of optical fiber in the sensor is divided into two categories: functional type (physical type) and non-functional type (structural type).
  • The functional type (physical property type) optical fiber sensor is a sensor composed of directly or indirectly modulating the intensity (amplitude), phase, polarization state, wavelength, etc. of the transmitted light in the optical fiber by using the measured physical quantity. Among them, the optical fiber not only plays the role of light transmission, but also is a sensitive element.
  • In the non-functional (structural) optical fiber sensor, the optical fiber is not a sensitive element, but only as a light transmission element. Generally, optical materials and sensitive elements are placed on the end face of the optical fiber or in the middle of two optical fibers to sense the change of the measured physical quantity, so that the intensity of transmitted light or reflected light changes accordingly for detection. Here the optical fiber is only used as the transmission circuit.

What is the test principle of COS functional test?

The input parameters are all legal and the conditions for execution are met. When the executed command should be able to be executed normally, check whether the tested command can correctly execute the designed functional steps.

How to address the internal registers of the MF RC500?

Can be addressed through a dedicated address bus. In this mode, the register bit UsePage-Select needs to be set to 1. Addressing within a page is allowed through the chip address pins A2, A1, and A0, and a paging mechanism is required to switch between registers of different pages.

What are the effects of fiber optic cables and connectors?

Fiber optic cables and connectors are immune to noise, light, RF interference, electromotive force (EMF), electromagnetic interference (EMI) and harmonics.

WWhat is a stand-alone CAN controller?

A stand-alone CAN controller is a controller integrated with a CAN protocol control module. All of its processor resources are used to implement and manage the communication functions specified by the CAN protocol specification.

Briefly describe the concept and classification of GPIB system devices?

There are various instruments and devices interconnected by GPIB bus. Some of them are very complex, such as computers, network analyzers, etc.; some are very simple, such as switches, attenuators and so on. But from the point of view of test system formation, they are all a logical unit in the system, only the test function is different. For the sake of simplicity and unity, the various devices that implement the IEEE488.2 protocol with different levels of complexity and functional capabilities are collectively referred to as “GPIB devices”. Simply put, any stand-alone device equipped with a GPIB interface is collectively referred to as a device. In the GPIB system, different devices undertake different tasks and perform different functions.
According to the different functions of the device in the system, it can be divided into three categories. 
(1) Controller device
(2) Speaker device
(3) Listener device
In a GPIB system, the role of a device is assigned by the controller in the system. Whether the device can implement the specified functions depends on whether the corresponding functional circuit is equipped in its GPIB interface circuit. The controller controls the work of the entire test system by sending a series of interface commands and management messages. For example, appoint devices as speakers and listeners. Arrange data exchange between them, receive service requests from them, etc. Each device (including computer interface cards) must have an address, so that the system controller can instruct which devices are speakers and which devices are listeners through addressing methods.

What are the characteristics of ladder diagrams?

• It can be concluded that the ladder diagram has the following characteristics:
  1. The vertical lines on both sides of the ladder diagram are called bus bars (sometimes only the left bus bar is drawn). Between the two busbars are the parallel logic rows (or steps) composed of the internal relay moving on and off contacts, and relay coils or functional instructions. Each logical line must start with a contact connected to the left bus and end with a coil or function command connected to the right bus.
  2. The left and right busbars in the relay control circuit diagram are power lines, and voltage is applied to each branch in the middle. When the branch is connected, current flows through the contacts and coils on the branch. However, the left and right busbars of the ladder diagram are not applied with voltage. When the branch in the ladder diagram is connected, there is no real current flowing, but an imaginary “current” for the convenience of analysis.
  3. The various devices (ie, soft components) used in the ladder diagram are called according to the corresponding names in the relay control circuit diagram, and are not real physical devices (ie, hardware relays). Each contact and coil in the ladder diagram corresponds to a storage unit of the component image register in the PLC storage area. If the storage unit is “1”, it means that the moving contact is closed (that is, the moving contact is disconnected). ) and the coil is energized; if it is “0”, the opposite is true.
  4. The state of the input relay in the ladder diagram uniquely depends on the on-off state of the corresponding input signal, and has nothing to do with the execution of the program. Therefore, the input relay cannot be driven by the program in the ladder diagram, that is, the coil of the input relay cannot appear.
  5. The auxiliary relay in the ladder diagram is equivalent to the intermediate relay in the relay control circuit diagram. It is used to save the intermediate result of the operation and cannot drive the external load. The external load can only be driven by the output relay.
  6. The contacts of each soft element in the ladder diagram have both moving and breaking. The number of moving and breaking contacts is infinite (and will not be damaged). How much is used, but the hard contacts of the input and output relays are limited and need to be allocated reasonably.
  7. According to the state and logical relationship of each contact in the ladder diagram, the ON/OFF state of the soft element corresponding to each coil in the diagram is obtained, which is called the logic operation of the ladder diagram. The logic operation of the ladder diagram is carried out in the order from top to bottom and from left to right, and the result of the operation can be used immediately by the subsequent logic operation. The logic operation is carried out according to the state in the element image register, not according to the state of the external input signal at the moment of operation.