1. Average cost per week
General-purpose Interface Bus: universal interface bus, which has two standards: ieee488 and iec625. The GUI standard consists of interfaces and bus. interfaces are composed of various Logical Circuits installed with each instrument and device for sending, receiving, encoding, and decoding of transmission information; the bus is a passive multi-core cable used to transmit various information.
In this test system, the bus on the agilente4447a spectrum analyzer conforms to the IEEE 488 standard and is a digital 24-foot parallel bus, it includes 8 data lines, 5 control signal lines, 3 hook lines, 7 ground lines, and 1 shielded line. It uses 8-bit Parallel Protocol, byte serial bidirectional hook and bidirectional asynchronous communication. The data unit is byte, and the data is transmitted as an ASCII string. The transmission speed is generally 250 ~ 500.
A controller (Computer) is used to control the bus and transmit instrument commands and data on the bus. The controller can address one speaker and one or more listeners, the data string is transmitted from the speaker to the listener on the bus.
The interface bus can be used to form a GUI instrument system. Its basic features include:
1) A bus can be used to connect to each other to form an automatic test system. In the system, the maximum number of instruments and equipment cannot exceed 15 (that is, the maximum number of instruments can be controlled by the GUI Controller), and the maximum length of the interconnect bus cannot exceed 20 meters;
2) Data Transmission adopts Parallel Bit (BIT) and serial byte (bit group) bidirectional asynchronous transmission mode, and its maximum transmission rate cannot exceed 1;
3) The message transmitted on the bus adopts the negative logic, the high level () is the logic "0", and the low level () is the logic "1 ";
4) address capacity. single-byte address: 31 speaker addresses and 31 listener addresses; dual-byte address: 961 speaker addresses and 961 listener addresses; for single-byte addresses, each device (including computer interface card) must have a 0 ~ The IP address of the port number between 30 and 30.
2. USB-GPIB Controller
Table Agilent 82357a technical indicators
General requirements |
|
Minimum System Requirements |
Windows 98 (SE)/ME/2000/XP/7 |
Software requirements |
Agilent Io libraries suite 14.0 or above |
Supported standards |
USB1.1 and USB2.0 IEEE 488.1 and IEEE 488.2 |
The error message returned when the error message returned. |
Parallel naming Pass Control Non-system controller mode |
General Features |
|
Power Supply |
USB Bus Power Supply Device, + 5 V, 500mA (max), 200mA (typical) |
Support for USB Hub |
Self-powered Hub |
Connection |
Standard 24-pin IEEE 488 Standard USB |
Cable |
2.5 m, shielded, connector rated 1500 Inserts |
Maximum data transmission rate |
More than 850kb/s |
Max connections |
Up to four 82357a instances on one computer |
Configuration |
Plug-and-play |
Indicator |
LED (ready, access, fail) |
USB (Universal Serial Bus) is a high-performance serial bus standard widely used, and is usually equipped with multiple USB interfaces on computers. It allows peripherals to connect to a computer without re-configuring the system. The computer can automatically identify the device and automatically install the corresponding driver.
The USB-GPIB controller (or USB-GPIB Interface Card) is essentially an interface protocol converter USB-GPIB controller to implement the function is to convert the USB communication protocol to the GUI protocol.
USB-GPIB controller has the following advantages:
1) the number of computer slots, addresses, and resource interruptions are not limited;
2) plug-and-play and hot swapping are supported to completely automate the connection between the host and the program-controlled device;
3) This is the best way to connect a computer to a Windows instrument and the fastest way to connect a computer to a Windows instrument.
The USB-GPIB Controller provides an effective way to introduce the unique advantages of USB into the automatic test system based on the average speed (0. In this test system, the USB-GPIB controller model used is Agilent 82357a. Table 3-1 provides some technical requirements for 82357a.
3. USB-GPIB communication between computer and spectrum analyzer
USB-GPIB communication between graph computer and spectrum analyzer
In this earth station antenna testing system, we only need point-to-point communication between computers and spectrum analyzers ., It is a system composed of computer, Gui cable, USB-GPIB controller and spectrum analyzer. Computer and controller, listener and speaker function, spectrum analyzer as the Speaker and listener, that is, the computer in each communication is always active, according to the need to send read/write commands to the USB-GPIB controller, however, the spectrum analyzer is always passive and responds to PC commands and data read/write requirements.
The general USB-GPIB controller is set to address 0, the spectrum analyzer can choose one from 1 to 30.