1. Introduction
The neutrality ties pours into the acceleration power source is a set of high-pressured high efficiency pulse power source which extremely fusion test installation (EAST) develops for national greatly scientific project superconductivity Tocker the Mark. This power source uses Pulse Step the Modulation[1] technology, becomes (Figure with 80 same 1100v/100A output’s power source module series 1), its specified output is: 80kv/80A, maximum pulse width 1000s. Because this power source puts in high-pressured, under the strong electromagnetic interference environment, therefore, must carry on the real-time monitoring to various power sources module condition, guarantees this electrical power system’s security and stability. Through to each kind of plan’s comparison, uses the computer RS232 mouth and DSP (Digital Signal Processor, digital signal processor) the RS232 mouth sets up the optical fiber network through the optical fiber switch. The overall system has the structure to be simple, the performance-to-price ratio is high, easy to expand, anti-jamming strong and so on merits.
Figure 1 acceleration extremely power source diagram and voltage output wave shape
1. Optical fiber network architecture
2.1 optical fiber network hardware
This optical fiber data acquisition network uses RS232 main line’s Shan Zhu much from the structure, the master station with PC machine, from the station with DSP, uses the multi-mold fibre-optic link, sets up always the linear optical fiber net. The optical fiber switch is 1 point 2 switch which manufacture, computer’s RS232 mouth data conversion light signal. DSP uses TI Corporation’s LF2407A.
This optical fiber network includes: Master station computer, single-channel optical fiber switch, 1 point 8 optical fiber switch and DSP composition. The network topology sees (Figure 2).
Figure 2 network architecture analysis situs chart
The DSP hardware system structure includes: A/D conversion fraction, the SCI connection, the I/O mouth and so on as shown in Figure 3. DSP needs to realize the function has, to power source module 8 switch quantity condition monitoring; Inputs terminal voltage’s monitor to the power source module, decided whether can close IGBT; Controls IGBT, the CKJ analysis and synthesis; Carries on the communication with the master station computer.
Figure 3 DSP hardware system structure
2.2 optical fiber network software
The master station uses LabVIEW compilation Windows system’s data acquisition contact surface [2] (Figure 4), simple easy to use. May according to need to establish the different parameter. Uses TI Corporation from the station in view of TMS320C2XX development set of integrated development environment CC (CODE COMPOSE) [3]. CC uses the graphical interface, provides the edition instruction, the parameter revision tool, can carry on the instruction level to TMS320C2000 series DSP the simulation and carries on the visualization the real-time data analysis, may raise exploiter’s working efficiency greatly, reduces the system development cycle.
The DSP multi-processor communication has two methods: Free line pattern and address position pattern [4]. Because the address position pattern under the high transmitting speed, the program speed is insufficient to avoid in the transmission class a 10bit free time, and the free line pattern and the RS232 communication are compatible, therefore this optical fiber network uses the free line communication pattern.
Figure 4 data acquisition contact surface
Master station through the COM1 mouth and from station communication, with software interruption method receive from station upload information. The master station receive and the transmission data is NRZ (non-nulling operation) the form, the NRZ form including the following constituent: An outset position, 1~8 data positions, a parity check position (may choose), 1 or 2 stop position.
Receives when from the station to a data, has an interrupt, and judges to be whether consistent with own virtual address. The master station with from the hypothesis which stands is as follows: From stands the virtual address from 01 to 80, when receives from the station data when is consistent with own address, the transmitter data gives the master station, otherwise is at the waiting accepting state (Figure 5), from the station the communication, identical only then does not give the master station frequently respectively from the station transmitter data.
Figure 5 program flow diagram
3. simulation debugging
With PC machine, 2 design the manufacture the DSP development board, 1 point 2 optical fiber switch has set up an optical fiber net (Figure 6), carries on the simulation debugging to the data acquisition network. The measuring instrument uses peaceful gram company’s TDS the 3032B oscilloscope. COM1 communication mouth’s 3 pin’s first rises with PC machine along is the trigger pip, the triggering level is 5V. The communication time test procedure is as follows: The COM1 communication mouth 3 pin transmission data’s first rise along takes the starting time, receives until 2 pins from the station upload data first rise along, this time namely with from stands time communication time for the master station. After tests many times, the communication has not presented the mistake, communication time is 560us (Figure 7), fluctuates in 20us, the data transmission speed hypothesis is 115200bps.
Figure 6 optical fiber data acquisition network hardware circuit
(1 is an optical fiber, 2 are the LF2407A chips, 3 are 1 point 2 optical fiber switch)
Data acquisition’s test procedure is as follows: Master station PC machine for from stands DSP to send out an address 76, each DSP after the judgment, the waiting, finally, the virtual address is 76 DSP (opens this power source module active status including IGBT/pass, fuse passes/breaks and so on) and the port voltage transmission for the master station computer. After the master station receives the data, to the data which receives carries on the analysis. If I/O receives this power source module’s active status is the abnormal condition, then DSP sends out a warning signal to the master control computer, the reminder staff shut off the module power source, simultaneously the data storage which gathers to the folder which assigns. If I/O accepts changes the power source module the active status is the normal state, then stored datum. Through tests the analysis many times, this optical fiber data acquisition network master station with one is 42.3ms (transmits 31 characters from the station communication’s mean time from station). Has not presented the communication breakdown in the test procedure, this optical fiber network satisfies the design target.
Figure 7 communication time oscillogram (1 transmission, 4 receives)
2. Antijamming effect comparison
RS232 is between the microcomputer the most commonly used serial communication connection, but RS232 serial communication connection’s antijamming ability is very bad. This is because RS232C uses the single end signaling, but its tie cable connects it two machine’s places connect in together, therefore, when between two grounding’s place electric potentials are inconsistent, has the syntype disturbing voltage production. Therefore has created the serious disturbance, even burns down the connection component; Along with frequency increase, twisted pair line line to weaken rapid markup, and the twisted pair line also has the so-called near-end crosstalk, namely, in the transmission line to and meets the recover of wire to have the electromagnetic coupling disturbance to between. If uses the fiber optic communications, may separate between two places the relations, thus sharpens its antijamming ability enormously. And the optical fiber also has the radiating capacity, the electric conduction, not to have the inductance, and in the fiber optics does not have the influence which the crosstalk as well as the light signal does not disturb mutually, also not the security problem which “the attachment place” the induction coupling will cause in the line.
With PC machine, 1 LF2407 development board, when uses the twisted pair line communication, in the COM1 mouth 2 pins receives the unwanted signal (e.g. Figure 7). Because the unwanted signal is too strong, has covered the effective transmission signal, causes the twisted pair line to be unable under this environment to work. Uses the optical fiber net to work under this environment, the antijamming effect is obvious, the unwanted signal has not affected to the communication. Therefore, the optical fiber is under this environment the ideal communication medium.
Figure 7 disturbance profile
5. concluding remark
This article innovation spot is: The SCI main line and the optical fiber communication medium unifies. Along with the DSP function’s unceasing consummation, DSP more and more is applying in the process control and the monitoring domain. And this network may with technical unions and so on industry ethernet, field bus constitute the distributional control system as well as the field bus control system, realizes the commercial run dispersion control. Uses the optical fiber switch cost which this article does to be low, easy network expansion. This article states the optical fiber monitoring network may apply in other high voltage isolation, the strong electromagnetic interference environment.
Reference:
[1] U.E.Schwarz “Gigitized high power modulation” 14th Symposium on Fusion Technology, Avignon, 1986
[2] Zhang Xiasong zhong Conkey corresponded the micro computer information in the LabVIEW local area network in 2004 the 12th issue of 49 page
[3] Luo rosy-colored clouds at dawn Zhang Gao records based on the TMS320LF2407A DSP MODBUS communication protocol realizes the micro computer information in 2005 the 7th issue of 138 page
[4] [US] Texas Instruments Incorporated, Xu Ke armed forces, translations and so on Zhang Xing, “TMS320LF/LC24 Series DSP CPU And Peripheral device” [M] Tsinghua University publishing house 2004 Has 217 pages to stop 221 pages.
