<正>The vacuum measurement and control system of the cluster target system is made up of many vacuum gauges, vacuum valves and vacuum pumps. There are two kinds of vacuum measurement and control unit, TPG261 and TPG256A. The first one just has one channel, and the other one has six channels. Both of them support RS232C interface which allows for operating the TPG261 or TPG256A via a HOST or terminal and can be also used for updating the firmware.