PC CONTROL OF INJECTION POWER SUPPLIESFOR THE BEPC STORAGE RING
S.Lu H.Ren H.Zhang R.Zhang,Institute of High Energy Physics, Beijing, Chinae-mail : hzhang@bepc3.ihep.ac.cn

abstract
interface to display data from power supplies and execute
A PC plays an important role to the power-supply

control functions.

control in the BEPC ring injection system. It functions asa gateway to set up a connection between the bitbus

1

BACKGROUND

network and the Ethernet network. The bitbus control
network consists of nine nodes, which control ring

The BEPC ring injection power supplies provide for 4

injection power supplies directly. The front-end signals

kickers, 2 lambersons, they are separately located at theare collected to the PC, and then any type of computers,

Neighborhood of e+, e- ring injection points. They had

which support TCP/IP protocol, can access the PC

been well controlled by self-developed pure hardware

through the Ethernet network to share the resources. The

system with a standalone mode from 1987 till 1996. The

PC is also used as a friendly man-machine interactive

main reason was to concern about that the strongmagnetoelectrical disturbing from large current pulse

with a bitbus interface and a self-developed digitalsources: kickers can lower the operation quality of theadapter HRCX910, which utilizes some digital anti-

main VAX-VCC-CAMAC control system.

disturbing measures to be sure the signal logic is right [1].

However, our consideration changed with new ideas.
We tried using the fieldbus: bitbus to perform thePAnalog controller: 4 differential inputs with 12 bit
resolution ranging 0-+10V. See Fig. 3.

distributed control over kickers and lambersons, rather

We use an iRCB 44/20A analog I/O remotethan turning the control into a part of the main VAX-controller with a bitbus interface and a self-developed

CAMAC control system.

analog adapter HRCX920 that utilizes some analog anti-After three-year hard work with our team members, a

disturbing measures and level transition [1].

new computer control system had been put into operationin BEPC in Nov., 1996. Two years operations have
proved the new PC-BITBUS distributed control system
succeeded. This is the first time to come true to apply afieldbus to BEPC control.

2 HARDWARE ARCHITECTURE
The interconnect hardware architecture for the new PCBITBUS distributed control system shows in Fig.1. It is
composed of 8 secondary stations and 1 master station. APC 586 with 100 MHz clock is located at the centralcontrol room as the system extension to act as a system
console. The stations operate as front-end I/O controllers.
The network works in the self-clocked mode with 375baud rate with two segments; the messages are transferred
to and from along the BITBUS network comply with theiDCX51 message format.
The secondary stations are sorted roughly to two types:

PThe digital controller: 12-bit digital output with one
clock plus several one-bit digital I/Os. See fig. 2.

Fig. 3. The analog station on the bitbus interconnect
The secondary stations are as close to the devices as
possible to reduce the magnetoelectrical interference.
The Master station is an iPCX344 intelligent bitbus
interface with PC bus. It provides a gateway between theIBM PC or compatible computer and the bitbus-based
distributed control environment [2].
The each distributed controller board on the bitbus
interconnect didn’t become in use till it was completely
configured through jumpers.
Bitbus cable is dual twisted-pair one with shielding tocarry signals safely.

3SOFTWARE ARCHITECTURE

The software for the new PC-BITBUS distributedcontrol system is classified into three parts:

P System software: the iDCX51 distributed control
executive on every stations, the iRMX for windows withnetwork version and MS-windows 3.1 on the PC, and lotsof system calls under different operating systems.

PUtility software: groups of software tool like Intel C
Fig. 2. The digital station on the bitbus interconnect

compiler, symbol debuggers, library functions, and many
development tools under MD-DOS for bitbus stations.

We use an iBCB 44/10A digital I/O remote controller

PApplication software: lots of application programs forthe PC-BITBUS distributed control system developed.

is divided into 4 zones: the analog readback display, theThe application software architecture for the interconnect

analog setting and trimming and standardizing, the deviceis shown in fig. 4.

status display, the device on/off controls. The control
page also provides menu selection to view device history
records, save useful setting data and choose the suitable
trimming steps, etc.

4PC FUNCTIONS IN THE SYSTEMThe PC is an extension to the bitbus interconnect,
therefore, the PC is a PC-BITBUS system controller. All
the commands come from the PC, All the real time
feedback messages show on the PC screen.
The PC is a gateway to exchange massages between
the bitbus interconnect and the Ethernet. We developed a
special program under iRMX for windows, it packs the all
messages concerning controlled devices to the string
format, then sends it to the main computer with TCP/IP
protocol, and it also unpacks the messages from the VAX
Fig. 4. System application software architectureand distributes them to the respective devices. The
program is ready to use. Now, through the Ethernet we

Performing control needs a bitbus driver for thecan logon to the PC to enter the common directory tonetwork communication, but it is unfortunate that there isview history records about the controlled device, even ftp

no such a driver under iRMX for windows V2.2. weto the directory to copy useful data freely.

explored a practical bitbus driver to lay the solid
foundation for the entire distributed control system.
The another bottleneck for the whole control system is
how to transfer the character messages under iRMX for

The PC is a work platform for the application softwaredevelopment and debugging as well as operating on it.
The PC is also an environment to manage entire system
control functions to operate smoothly.

windows into the graphic ones with MS-windows style.

5

As matter of fact, the iRMX-net network communication

CONCLUSION

protocol: Dynamic Data Exchange is used in order tosolve the problem and the necessary system software

A variety of fieldbuses has been turned up nowadays,

configuration for it is also needed to create a successful

like Canbus, Profibus, Lonworks, etc. As a front-end I/O

communication channel between them.

device control network, fieldbuses are reliable andThe PC accesses to secondary stations through thebitbus interconnect by a set of high-level commands andconfigurable, are getting more and more popular. The PC
will often accompany in the fieldbus applications.

responses: the Remote Access and Control interface,REFERENCES

which is built on top of the bitbus message protocol andresides on all stations as a preconfigured task [2]. We call

[1]

RAC services to access I/O on remote stations directly.

injection power supplies”, p1754, EPAC96 proceedings.

The man-machine interactive graphic interface is theanother important characteristic. The console control page[2]

h.zhang, others, “a control system for BEPC ring
“iPCX344 intelligent bitbus interface user’s guide”,

published by intel corporation, 1987.