The 9th Symposium on Accelerator Science and Technology, Tsukuba, Japan1993

Improvem ent of 1t 2 Beam Line Control
Y.Suzuki, M.Takasaki, M.Minakawa, H.lshii,Y.Kato, M.Ieiri, K.H.Tanaka, H.Noumi,and Y.Yamanoi
KEK National Laboratory for High Energy Physics
1-1 Oho, Tsukuba, Ibaraki 305, Japan

Abstract

1) at the control panel of the beam line, select amagnet power supply by multiplexer switch;
This paper reports the latest improvement of n:2 2) press check(reset)-s witch, check fault indibeam line control. The n:2 beam line has eight sets of cation lamps;
magnet and magnet power supply. On this 3) tum on power switch, check the ON lamp light;
improvement, a microcompute r had embedded in 4) check the output current to be 0 ampere or not;each .of the power supplies. The microcompute r 5) set the output current by push-button switch. It
operates the power supply, watches the condition, and takes about two and half minutes;
sends more details to a control computer of the beam 6) check the stability of the output current by digitalline through GPIB (IEEE-488) high way. As the meter;
results, the control computer has released from 7) set the current to 0 ampere, and tum off the power
operation and surveillance of the power supplies, supply.
and the maintenance work has become more
efficient.
It took about six minute with quick operation tocheck up one power supply.
Another weak point of this control system is that,in the counter hall, the experimental area and beamlines are occasionally rearranged, but the control
I. INTRODUCT ION
panel and rack is not so easy to move here or there.
Next system consisted of a personal computer,At first, we review the old control systems of n:2 interface devices, and a CRT terminal. On thisbeam line, and make clear what system is better for system, the power supplies were the same as before,
the beam line control. Mter this section, a power then the same signal cables were connected to thesupply contro1ler, the function of the power supply interface devices. But the operation ability of thecontrol1er, and the control system of n:2 beam line beam line was noticeably improved, and it afforded
satisfaction that the CRT terminal could be removed
are described in section II, III, and IV respectively.
Now at the KEK 12 GeV proton synchrotron (KEK- with ease. Then the check up work of the magnets
PS), there are more than 150 sets of magnet and and the power supplies was done in a short time, andmagnet power supply in two experimental halls a schedule for maintenance work of beam lines
could be laid out effectively. But there were a few(North counter hall and East counter hall ).
dissatisfactions. They are listed below:
Since the KEK-PS was commission in 1976, n:2
beam line has been used for many experiments as
the oldest beam line in the East counter hall. The 1) increase of the devices which require check up:
beam line has been continuously operated for two or 2) increase of difficulty to point out a trouble part on
three weeks running and for three days stop. In this the control system. Especially, the interface devices
operation schedule, on the three days, the magnets, are not easy to check, and it takes two staff, or need
the magnet power supplies, and other devices in one staff and a special tool or another computer formany beam lines have to be maintained. But those testing them;pressing work became available to do efficiently in 3) at the rearrangemen t of beam lines, the control
cables between the interface devices and the powera short time by the improvement of control systems.
About 17 years ago, n:2 beam line was constructed. supplies are not easy to use again as resource, though
The control system of the magnet power supplies was the cost of cables is high;that the control panel and rack was connected 4) by the increase in number of power supplies, thedirectly to power supplies. Through this control computer efficiency for control and surveillance issystem, it took much time to check up magnets and lowered.
magnet power supplies. For example, the process ofthe check up is listed below:

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2,

3,
4,5,

II. POWER SUPPLY CONTROLLERAs the solution of the above dissatisfactions, efforts
were concentrated upon to develop a power supply
controller (PSC) as a part of magnet power supply
rather than to introduce a higher performancecomputer or data highway. Fig. 1 shows the PSC.

reset of interlock circuit;selection of polarity ;selection of regulation mode (voltage /current);
selection of remote or local control;

monitoring points:
1, control power ON/OFF;2, remote/ local;
3, power switch, ON/OFF;4, polarity +I-;5, magnet #1 ready/ trouble;
6, magnet #2 ready/ trouble;
7, fault; de over current;
8, fault; de current leak;
9, fault; over heat #1;
10, fault; over heat #2;
11, fault; cooling fan;
12, fault; magnet power supply's door open;
13, fault; magnet #1; over temperature;
14, fault; magnet #1; failure of cooling water flow.

Ill. PSC AND MAGNET POWER SUPPLY
The soft program of the PSC was developed for
reducing the load of beam line control computer,then all the operation of magnet power supply is doneby the PSC.
The procedure of magnet power supply operation
for a current setting message received is listed
below:
Fig. 1. Power supply controller.
Step-1, PSC receives a "A xxx.xx" current settingfrom a beam line control computer.
messageIEEE-961)(STD:boards
The PSC consists of fivethe operation program of magnet power
invoke-2,below.
listedasfunctionswhich havesupply.
-3, check interlock fault signals.
(1) CPU board: Z-80 cpu and GPIB interface.
-4, check low voltage power supplies, output current,(2) DAC board: 16-bit DAC for reference voltage.
(3) ADC board: 16-bit ADC for monitoring the output and DAC output voltage.
-5, set the magnet power supply to current or voltage
current of magnet power supply.
(4) ADC board: 12-bit ADC and 16-channel multi- regulation mode.
plexer. This board is used for monitoring the -6, check polarity, and turn reversing switch.
-7, turn on power switch, and check its status.
following values:-8, current setting.
1, reference voltage (16-bit DAC);-9, after current setting, send SRQ(service request:
2, de output voltage;on this case this interrupt signal is used to report the3, wave form of the output voltage;
end of current setting).
4, AC input current;
5, voltage of a point in the current control loop of -10, set the limit values of the output current forwatching program.
magnet power supply;watching and check status: ON/OFF, inter-11,supplies.
power
6, seven points on low-voltage
lock signals, remote or local, output current,(5) relay I/0 board: for control and monitor of the reference DAC, and low-voltage power supplies.
following points.
Control points:
1, power switch ON/OFF;-77-

At this state, by a "A-xxx.xx" message whichmeans to set current to negative xxx.xx ampere, thefollowing steps are done:-12, current setting starts to 0 [A].
-13, tum off power switch: OFF.
-14, jump to the above step 2.
-15, the final state has negative output current:(-)
xxx.xx ampere
At this state, by a "V + xx.x" message, thefollowing steps are done.
-16, current setting starts -xxx.xx[A] to 0 [A].
-17, tum off power switch.
-18, jump to above step 2. and the final state has
positive output voltage; (+) xx.x volt.
At the OFF state, by "CK" message:(check), thefollowing steps are done.
-19, reset interlock circuit, check fault signals.
-20, check the output voltages oflow-voltage power
supplies, DAC, and output current.
-21, tum reversing switch, check its status.
-22, turn on power switch, check its status.
-23, check the output voltages oflow-voltage power
supplies, DAC, and output current.
-24, turn off power switch, check its status.
-25, send SRQ signal to indicate the check-end.
By the above PSC operation, the computer of thebeam line control is released from the each operationof magnet power supplies. Therefore, the efficiencyof the computer is not lowered by the increase in
number of magnet power supplies.
On this system, at a trouble of magnet power
supplies, the PSC makes a report as words whichindicates clearly what trouble is occured, and what
electric part is needed for the maintenance. It
greatly helps for the maintenance staff.

Beam line controller..___ _to user terminal
RS-232c

GPIB
coaxial cable & bus extender

IV. CONTROL SYSTEM OF n2 BEAM LINE
At the improvement of 7t2 control system, the PSC
was installed in each of eight magnet power suppliesof 7t2 beam line, and those PSCs and a computer forthe beam line control were connected by a single
GPIB high way: coaxial cable.
The computer is HP9000-300: personal computerwith BASIC language. The GP-IB was extended by
GP-IB extender: HP-37204A. The soft program forthe beam line control was written by BASIClanguage.
The construction work of this new control system
of 1t2 beam line had done with ease during the twomonths in the summer shut down of 1992. At theconstruction of control wiring, the cost and the periodof time was lowered into the minimum by GPIB highway.
Since the control system has been used for not only
usual operation but check up work usefully.
The computer has showed sufficient performance,and the GPIB high way has too. But the reason of thegood performance is mainly due to the PSCs. The
computer and the GP-IB high way are almost in idle
state, though the PSCs are always operating andwatching the magnet power supplies on the system.

V. CONCLUSION

By introducing of the magnet power supplies withPSC, the control system has given the results, notonly good performance than the before, but also
rationalization in the construction and themaintenance of beam lines. It has reduced costs,manpower, and time.
At present, there is a plan to set up one moremagnet power supply (with PSC) in 1t2 beam line,
and the extension work of the control system isexpected to be completed with ease and in a shortperiod of time.

magnet power supplyFig. 2. 1t2 beam line control system.

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