UPGRADE OF THE POWER SUPPLY INTERFACE CONTROLLER
MODULE FOR SUPERKEKB
T. T. Nakamura#, A. Akiyama, K. Furukawa, M. Iwasaki, H. Kaji, S. Sasaki, KEK, Ibaraki, Japan
Abstract
There were more than 2500 magnet power supplies for
KEKB storage rings and injection beam transport lines.
For the remote control of such a large number of power
supplies, we have developed the Power Supply Interface
Controller Module (PSICM), which is plugged into eachpower supply. It has a microprocessor, ARCNET
interface, trigger signal input interface, and parallelinterface to the power supply. The PSICM is not only aninterface card but also controls synchronous operation of
the multiple power supplies with an arbitrary trackingcurve. For SuperKEKB, the upgrade of KEKB, most of
the existing power supplies continue while hundreds of
new power supplies are also installed. Although thePSICMs have worked without serious problem for 12years, it seems too hard to keep maintenance for the next
decade because of the discontinued parts. Thus we havedeveloped the upgraded version of the PSICM. The newPSICM has the fully backward compatible interface to thepower supply. The enhanced features are high speed
ARCNET communication and redundant trigger signals.
The design and the status of the upgraded PSICM arepresented.

Fig. 2 shows the details of the interface between thePSICM and the power supply. The hardware
specifications of the PSICM are listed in Table 1.

INTRODUCTIONKEKB is an asymmetric electron-positron collider,which is dedicated to the B-meson physics. Its operation
started in December 1998 and finished in June 2010. The
KEKB accelerator control system has been constructedbased on EPICS (Experimental Physics and Industrial
Control System) tool kit. EPICS provides coremechanism for the distributed control system. EPICS
runtime database is running on a local control computer
called IOC (Input/Output Controller). More than 100
VME/VxWorks computers were installed as IOC in theKEKB accelerator control system. Several server
workstations (HP-UX and Linux) are also installed to run
the high level application programs. The runtime databaseis downloaded from the central server workstation whenthe IOC starts up.
In the KEKB storage rings and the injection beamtransport lines, about 2500 magnet power supplies are
installed [1] and controlled by 11 IOCs. To connect such alarge number of power supplies to the IOCs, we adopted
ARCNET as the field bus and developed the PSICM(Power Supply Interface Controller Module) [2], which is
the ARCNET interface board for the power supply. The
PSICM has the shape of 3U Euro-card format (100mm ×160mm) with a DIN 64-pin connector and can be plugged
into the power supply. Fig. 1 shows the photo picture ofthe PSICM and the magnet power supply with PSICM.
___________________________________________# tatsuro.nakamura@kek.jp

Figure 1: whole shape of the PSICM (above) and thePSICM plugged in a magnet power supply (below).
The ARCNET allows using several kinds of media. We
adopted shielded twisted-pair (STP) cable as the media
and HYC2485 as the media driver. This configuration
allows up to 20 ARCNET nodes to be connected on single
segment in the daisy chain manner. The STP cableincludes an auxiliary twisted-pair for the external trigger
signal together with the ARCNET. Fig.3 shows typicalconfiguration of ARCNET used in the KEKB magnet
power supply control system.

tracking pattern calculation on IOC
data transfer through ARCNET

Power Supply
Power On/Off,Reset, etc.

synchronous start signal

7-bit momentarysignals

ARCNET

PSICM

Registers

output current
min. 1 ms

NVRAM

max. 4096 steps(Original PSICM)

16-bit I/O

DAC

Figure 4: Schematic diagram of synchronous operation.

Latch

NEW VERSION OF THE PSICM

Interface between Power Supply (PS) and PSICM–TTL Output (PS m PSICM)
••
••

–

TTL Input (PS o PSICM)••–7-bit momentary output
16-bit parallel output
5-bit address
3-bit strobe (Read, Write, DAC write)
16-bit parallel input
1-bit attention (interrupt request)

PSICM assumes some registers in the PS.

Figure 2: The interface to the magnet power supply.

Sync. Start Signal

ARCNET Interface board
㸦4 ch. / boards㸧
PSICM

CPUPower
SupplyIOCmax. 20 nodes
Twisted pair Cables
Local Control
RoomPower SupplyStation ARCNET㸦1 pair㸧 Sync. Start Signal㸦1 pair㸧Figure 3: Typical configuration of ARCNET in KEKB.
The PSICM is designed to control the output current of
the power supply according to the arbitrary tracking
curve. The tracking data are sent from the IOC to thePSICM as an array of the output current values. After
receiving the data the PSICM start tracking by a startcommand or an external trigger signal. Fig. 4 shows theschematic diagram of this sequence. Using the external
trigger signal all magnets in the storage ring can besynchronously operated. The sequence control of thesynchronous operation is performed by the IOCs with thearbitration by the server process on the central
workstation [3].
The magnet power supplies of the Photon Factory
Advanced Ring (PF-AR) in KEK are also controlled in
the similar manner using the PSICM.

For the SuperKEKB, the upgrade of the KEKB,
significant numbers of power supplies are newly
manufactured. The PSICMs have worked in KEKB for 12years. During these years some of the parts have been
discontinued and it becomes much harder to reproduce
the PSICM. At this moment we decided to develop thenew version of the PSICM.
In this decade the Ethernet becomes much popular andwide variety of the inexpensive commercial products
become available. We think the Ethernet is the mostprobably surviving technology in the next decade. Once
we thought Ethernet could be candidate as the field bus
for the new PSICM [4]. On the other hand ARCNET isstill available in the market. The cost of the development
can be minimized when we adopt ARCNET again
because the application-level communication protocol
defied for the original PSICM can be reused without any
modifications. ARCNET controller chip, which takes careof ARCNET protocols, is available. It enables softwaredevelopment much easier. This is also the advantage ofARCNET. We also have to consider the option of thepartial replacement of the PSICM depending on thebudget. In such case the mixture of ARCNET andEthernet is undesirable. Thus we decided to adopt
ARCNET again.
Table 1 shows the hardware specifications of the new
PSICM together with the original one.
Table 1: Hardware Specifications
Original PSICM

New PSICM

Microprocessor

AM186

MPC8306

Clock frequency

20MHz

133MHzData memory

256kB SRAM

128MB DDR2
SDRAM

Program memory

256kB EPROM

64MBit NOR
FLASH

ARCNET
interface

2.5Mbps
Backplane mode

2.5/5/10Mbps
Backplane mode

Controlle

COM2002

COM20022

Media driver

HYC2485

HYC5000

Power required

5V 0.4A

5V 1A

COMPATIBILITY AND NEW FEATURE
Compatibility for the power supply
The specifications of the interface to the power supply
are fully backward compatible to the original PSICM. The
new PSICM can be plugged into any existing power
supplies.

Compatibility for the control software on IOC
The application-level communication protocol between
the IOC and the new PSICM is backward compatible tothe original PSICM. All of the command messages
defined for the original PSICM can be accepted also by
the new PSICM. In addition some extensions are
introduced because of the additional features describedbelow.

For mass production we are planning to produce 3000modules. First mass production of 1000 modules is inprogress. It is scheduled to be completed in March 2014.

UPGRADE OF THE RELATEDHARDWARE
We have also upgraded the related hardware. One is theVME board of the 4-channel ARCNET interface. It canaccept dual synchronous start signals and deliver them
together with the ARCNET. It also supports the highspeed ARCNET communication (10Mbps, 5Mbps and2.5Mbps). Another development is the upgraded
ARCNET hub, which also supports the high speed
communication and the dual synchronous start signals.
Mass production of them has been already completed. Fig.
6 shows these products.

Additional features of the new PSICM
Following are major changes.
(1) The high speed ARCNET communication issupported. 10Mbps, 5Mbps and 2.5Mbps aresupported for the new PSICM while the original
PSICM supports 2.5Mbps only.
(2) 32-bit data handling of the tracking data array isavailable in order to support high resolution DAC(24-bit, 20-bit and 18-bit). The original PSICM
supports 16-bit DAC only. (Later special version
for 18-bit DAC was developed based on theoriginal PSICM. But this version was ad hoc andlimited.)(3) Dual trigger inputs for synchronous start signals
are available. This feature enables trigger signals
redundant. More reliable synchronous operation isexpected.
(4) More reliable RJ-45 connectors which have
optional protectors against dust are adopted.

STATUS OF THE NEW PSICM
Now we have finished the test of prototype modules of
the new PSICM. Fig. 5 shows the prototype #2, which isalmost final version.

a)b)

Figure 6: a) 4-ch. ARCNET interface board (VMEmodule) of original version (left) and new version (right);b) ARCNET hub of new version mounted on the top ofthe test bench.

CONCLUSION
We have developed the new PSICM for SuperKEKB. It
is backward compatible to the original PSICM. Several
enhancements are introduced. The high speed ARCNET
communication is expected to enable more efficient
operation of the magnet power supplies. Wide variety ofthe high resolution DAC can be supported by 32-bit data
handling. Dual trigger input for the synchronous startsignals, together with the dust protectors of the RJ-45
connectors, is expected to enable more reliable and stable
operation of nearly 3000 magnet power supplies.

REFERENCES[1] M. Yoshida et al., “Magnet Power Supply System for
KEKB Accelerator”, EPAC-98, Stockholm, 22-26
June 1998
Figure 5: Prototype of the new PSICM.

[2] A. Akiyama et al., “KEKB Power Supply Interface
Controller Module,” ICALEPCS’97, Beijing, 3-7
Nov. 1997.
[3] T. T. Nakamura et al., “Magnet Power Supply
Control System in KEKB Accelerators,” TC1P40,
ICALEPCS’99,
Trieste,4-8Oct.
1999;
www.jacow.org[4] T. T. Nakamura et al., “Prototype of the Ethernetbased Power Supply Interface Controller Module for
KEKB,” WEPEB002, IPAC’10, Kyoto, 23-28 May
2010; www.JACoW.org