Design and Application of HIRFL-CSR Vacuum Control System

　　introduction

　　The installation and leak detection of non-standard parts and standard equipment of the main ring vacuum system of the HIRFL-CSR (Lanzhou Heavy Ion Accelerator Cooling Storage Ring Project), a major national "Ninth Five-Year Plan" scientific project, was completed in early 2004. After baking, the vacuum degree reached an ultra-high vacuum environment of 10-11mbar. There are hundreds of high/low vacuum pumps placed on the accelerator injection line, the main ring vacuum cavity and the beam transport line, and nearly a hundred vacuum gauges and high vacuum power supplies that need to be detected and controlled. In order to realize the remote opening/closing of various vacuum gauges and high vacuum power supplies, the vacuum gauge readings and status are regularly detected, and abnormal (set point out of bounds) alarms and prompts need to be provided to the central control center. During operation, a vacuum failure in any beam line of the ultra-high vacuum system will cause serious consequences such as beam loss, instrument damage, and accelerator shutdown. Therefore, the accelerator must have a fast-response, safe and reliable vacuum protection and control system.

　　1 System Hardware Composition

　　The core of this control system is the independently designed control module VAC400 based on MSP430F149, which is compatible with various vacuum gauges, vacuum pumps and high vacuum power supply requirements. Each module is connected to one or more vacuum gauges or vacuum pumps to collect their analog/digital quantities and status codes. The data is uploaded to the central control machine via the RS-485 serial bus for online monitoring/display, and the measurement and control commands sent by the central control machine are directly applied to the vacuum gauge, power supply or solenoid valve to complete the patrol detection and control. Each VAC400 has a unique identification code (or address). Each RS-485 line can connect up to 32 VAC400 modules. In each communication cycle, only one slave computer is allowed to communicate with the host computer. The communication connection adopts handshake mode. The data collected by ADC is continuously and automatically updated and sent to the host computer for reading and display. The communication rate between VAC400 and vacuum gauge is 9600bps. INTRANET users can access the host computer to operate specific functions of specific vacuum gauges.

　　2 System Software Design

　　The key to the design of the system software is to design the control commands for different instruments and equipment, such as the vacuum gauge IM520, vacuum gauge IT23 and vacuum pump GST-03L, and to output the results consistent with the data type and unit actually displayed by the controlled instrument. At the same time, when the central control center issues other operation commands for this device or other devices, it needs to be able to generate interrupt execution and obtain the corresponding data. For different controlled devices, we change the corresponding main function part injection module, thereby realizing complex and changeable system tasks.

　　2.1 Vacuum gauge IM520 control part program

　　The system needs to obtain the vacuum value data of the vacuum gauge IM520, and the vacuum value and the voltage value have a complex functional relationship. Since MSP430 cannot calculate complex functions, only the voltage value is displayed by MSP430, and the subsequent conversion needs to be designed by other software. The ADC register of MSP430 can display hexadecimal integers. The human-computer interaction interface requires an intuitive decimal floating-point voltage value with three decimal places. The following ADC function implements this function:

　　void ADC（void）

　　｛ unsigned tra[4]; int j;

　　TXBUF1=ADDRESS; // Output the module name and add ";" and a space after it

　　while （（UTCTL1&0x01）==0）;

　　TXBUF1=58;

　　while （（UTCTL1&0x01）==0）;

　　TXBUF1=' ';

　　while （（UTCTL1&0x01）==0）;

　　if (Buffer[2]=='r') //Determine whether to input the command to read ADC data

　　｛

　　for（i=0;i<4;i++）

　　{ADC12CTL0 &=～ 0x02; //First reset the ADC conversion enable when setting

　　ADvalue[i]=ADC12MEM[i]; //Read data

　　/*Convert the read hexadecimal number into a decimal floating point number with three decimal places*/

　　tra[i]=ADvalue[i]＊10000.00/4095.00;

　　ADbit[0]=between[i]%10;

　　ADbit[1]=（between[i]/10）%10;

　　ADbit[2]=（between[i]/100）%10;

　　ADbit[3]=22;

　　ADbit[4]=（between[i]/1000）%10;

　　/＊Loop output the data in ADC12MEMx＊/

　　for（j=4;j>=0;j——）

　　｛

　　TXBUF1=Hex2ASCII（ADbit[j]）;

　　while （（UTCTL1&0x01）==0）;

　　｝

　　TXBUF1=' '; // Output space and the next set of ADC data are separated

　　while （（UTCTL1&0x01）==0）;

　　｝

　　TXBUF1=13; //Wrap after displaying data and execute the next cycle display

　　while （（UTCTL1&0x01）==0）;

　　ADC12CTL0 |= 0x02; } // Enable ADC conversion

　　｝

　　The data of the vacuum equipment monitored by the vacuum gauge needs to be automatically transmitted to the central control center in order to achieve real-time monitoring. The following program part realizes that the control module with MSP430 F149 as the core automatically transmits data to the remote control computer. [page]

　　void main（void）

　　｛ int i=0,j=0;

　　WDTCTL=WDTPW+WDTHOLD; //Stop watchdog

　　_EINT(); //Open the general interrupt

　　Init(); //Initialize ADC

　　ADC12CTL0 |= 0x01; //Start conversion

　　while（1）

　　{P4OUT &=～0xC0; //Indicates that the LED is off

　　display: stop1=0; //goto loop structure entry

　　delay（0xFFFF); //delay program call

　　if（stop1==0）

　　{IE2 &= ~URXIE1; //Stop USART1 RX interrupt P3OUT |= 0x01;

　　ADC(); //Call ADC function

　　Buffer[2]='r'; //A command to read data from the vacuum gauge IM520 that is different from other tasks

　　Command key characters

　　delay（0x1FFF）;

　　ADC（）;

　　Buffer[2]=‘r‘;

　　IE2 |= URXIE1; //Enable USART1 RX interrupt

　　P3OUT &=～0x01;

　　｝

　　else goto display; ｝

　　｝

　　2.2 Vacuum gauge IT23 control part program

　　The COMBIVAC IT23 vacuum gauge is a three-way vacuum gauge input, front panel or RS-232C (9-pin D-type port 9600bps) interface control and data readout. The front panel LCD displays four items: Torr, Micron, Pa and mbar. And the remote control machine needs to input the "uni w mbar or Torr or Pa or Micron" operation command to convert and read out various types of data content online.

　　void main（void）

　　{ char IT[4][15]={"uni w mbar\\0","mes 1\\0","mes 2\\0","mes 3\\0"}; // Vacuum gauge IT23 operation command

　　int i=0,j=0;

　　/…Same as the control part of vacuum gauge IM520…/

　　display: delay（0x1FFFF）;

　　if（stop1==0）

　　｛ IE2 &= ～URXIE1;

　　P3OUT |=0x01;

　　for（j=0;j<5;j++） //Loop and execute the command and display the data

　　｛

　　for（i=0;IT[j][i]!=‘\\0‘;i++）

　　｛ Buffer[2]=‘w‘;

　　OperateIT23（）;

　　TXBUF0 =IT[j][i];

　　while （（UTCTL0&0x01）==0）;

　　｝

　　/…Same as the control part of vacuum gauge IM520…/

　　else goto display; ｝

　　｝

　　3 Conclusion

　　The operation shows that the data obtained by the vacuum control system based on MSP430F149 has good accuracy and stability, and it can complete the real-time monitoring and display tasks of vacuum equipment. Due to the advantages of low cost, high speed, low power consumption and high precision, the system can also be applied to safety protection detection, access control interlocking linkage and water and electricity detection systems.