The Realization Of Program-controlled Matrix Switch

In automatic testing feild, switch system controls the direction of signal transmission,it is the bridge between control system and units under test, and it is also an importantinterface comonent of testing system. Matrix switches are applied in many kinds ofdifferent industrial test occasions and gets more and more favour of professionals, becauseit can be suit for extensive area and its operating methods is very universal. Matrix switchis a kind of switch device with a structure that row and column cross arrangement. It’severy crosspoint connect a specific row or column so its every crossconnect node canoperate independently, and the routing of signal can be realized by seting up differentcrosspoints. Matrix switch is the indispensable component of a testing system and it’s alsothe critical part to realize the generality function, so people expect that this kind of switchsystem can be more portable, have higher speed and some other advantages.This paper designed a programmable matrix switch system, by which users canchoose any one or more module unit to test, and the system can control thousands of unitsat the same time, and can expand more control unit according to the actual need of the testobject. This paper introduces the system selectied scheme and the main communicationprotocols, the principle and function of each module in the software and hardware systemis discussed in detail. This system selected the embedded microcontrollerSTM32F103RET6which is famous for the high performance and low power consumptionas it’s controller chip, and made full use of its own peripheral modules to reduce the wasteof resources. Through the transplantation of TCP/IP protocol stack LwIP and the use ofENC424J600, conveniently realize the network communication between the PC andprogrammable matrix switch. Choose reed relays as switching device at the matriccrosspoint in the switch unit which can expanded by system, and the on-off order can beexecuted through the drive of shift registers. The control unit receive control commands from the PC, and transfer these commands to the switch by the SPI bus with serial dataform, and then connect the measured unit to execute assigned control. The control of PCoperating is realized by programming Python language, its interface is clear, simple andeasy to handle. The matrix switch system can be applied to many industrial test area, it canrealize the test requirements such as the voltage, current, load and so on. At last, brieflydescrip the system test method.