arecibo telescope servo & drive system - 1 - technical meeting may 2004 vertex antennentechnik...

Arecibo Telescope Servo & Drive System - 1 - Technical Meeting May 2004

VERTEX ANTENNENTECHNIK GmbH

Arecibo Telescope Servo Drive System

Ideas For Computer Upgrade



VERTEX Ser vo Contr ol System " ARECI BO"

M: Mot orP: Pinion

G: Gear box

W: Wheel

E: Encoder

f our ident ical unit s

fi ve ident ical unit s

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CH

#1

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D3\ O&M\ BS5034.SKD/ 2.2

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1x GD + 1x CH

2x

E

E

M G

M G

Az

Dri

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Syste

m

W

W

t o host comput er

Por t able Cont r olUnit (PCU)

Compoments suggested to be replaced during Computer Upgrade

Mot orCont r oller#2




moni

tori

ng &

con

trol

I RIG- B

moni

tori

ng &

con

trol

Oper at ion Cont r olUnit (OCU)(in main cont r ol r oom)

LAN

Main CPU

DCS

Dr iveCont r olSyst em


DCS

setp

oint

s

Pr ogr ammableLogic Cont r oller

Et her net Module

IRIG- B Time Code Reader

CP 581(AT 386)

PLC

RS232

COM2

CP524

Local Cont r olUnit (LCU)

TTY

FORS232

FORS232

DP RAMDat a



Computer Upgrade Concept I

(Existing) PLC hardware can be re-used to

a large extent hardware (except CP581) is

still will be available for many years

CP581 will be removed PLC function will be limited

to safety functions and low level operation

interface to servo computer via serial interface (new card) – not time critical!

New Servo Computer Local User Interface

(replaces existing LCU) tasks:

• encoder readout• operating mode control• M&C Interface to host• position loops

output to DCS:analog velocity commands



Computer Upgrade Concept II

Drive Control motors to be re-used servo amplifiers to be re-used complete DCS to be re-used additional setpoint from servo

computer:• DCS boards can handle

additional setpoint• analog signal must be wired

from backplane SUB-D connector to board connector

• PLC software must control selection relay

Encoders presently read by PLC new (possibility 1)

• only computer reads encoders

• position dependent PLC interlocks cannot be kept

or (possibility 2)• install SSI doublers• both computer and PLC read

encoders• position dependent PLC

interlocks can be kept



Computer Upgrade Concept III

OCU in main control room also to be replaced new OCU could be …

• a desktop PC with keyboard and mouse, running on Windows

• a rack mounted touch screen panel PC

• a notebook PC logs into servo computer via

Ethernet existing serial link no more

required

Interface to host computer remains on Ethernet protocol

• … could be kept• … or extended/modified

according to present experience

• … or completely changed



Contr ol System af ter Computer Upgr ade

M: Mot orP: Pinion

G: Gear box

W: Wheel

E: Encoder



G

G

El

Dri

ve

Syste

min

cl.

CH

#1

Dri

ve

S

yste

m

D:\PROJ\AKTUELL\BS_Arecibo_new.SKF/2004-05-24

P

1x GD + 1x CH

2x

E

E

G

M G

Az

Dri

ve

Syste

m

W

W


New Components



M

M

M


t o host comput er

FO


DCS

setp

oint

s

TTY


moni

tori

ng &

con

trol

moni

tori

ng &

con

trol

Main CPU

DCS


PLC

SSIdoubler

SSIdoubler

IRIG- B

LAN

LAN

CP524

Oper at ion by t ouch scr eenor keyboar d & mouse

(in main cont r ol r oom)

FO

Ant ennaCont r ol Unit

LocalUserInt er f ace

CP524

Oper at ion Cont r olUnit (OCU)

LAN

RS232LAN


ACU



Possibilities for Servo Computer

PC in-expensive easy replacement / upgrade interface boards to encoders

etc. to be found existing application software to

be adapted to hardware and software platform

reliability for operation unknown becomes obsolete very fast spare part availability

Industrial Servo Computer proven reliability all interface hardware

available interface modules comply to

more stringent specifications spare part availability application software available

to a large extent prepared for future upgrades more expensive than PC software and drivers written

for a particular hardware configuration



Vertex Antenna Control Unit 8100

Vertex Antennentechnik’s standard controller for high accuracy antennas and telescopes since 2001

Installed at ESA 35m Deep Space Antenna (servo accuracy ~2 mdeg)

• Australia: in operation• Spain: presently being built

various (fast) ESA 15m antennas (~20 mdeg) ALMA Radio Telescope (~0.15 mdeg) APEX Radio Telescope (~0.15 mdeg) AMIBA Hexapod Telescope (~3 mdeg) CNR 32m Radio Telescopes at Noto and Medicina (~1 mdeg) Eumetsat Polar Station, Svalbard (~20 mdeg) various other stations

Several more installations in progress




Concept: CompactPCI bus VxWorks 5.5 RTOS P III 1.3 GHz CPU with 2 Ethernet

interfaces 10.4” Color Touch Screen as local

user interface (separate PC running on Embedded XP)

multiple user interfaces feasible several types of interfaces to host /

encoders / drive cabinet available

Tasks: drive control

• fully digital Az/El drive control or• position loop only with analog

velocity command output

position readout from encoders operating modes interlocks on software level local control of all functions pointing error correction (option) communication to interlock

system PLC Interfaces to host computer



ACU 8100 Components

ACU_Arecibo_KOMP.SKF/21.05.2004

field buses to/frommetrology sensors

(for fully digital systems)

COM2

Main CPU (Pentium III)

COM1

ACU Front Panel(colour touch screen)

Azimuth Elevation

234.5678° 87.6543°

STOP PRESET

Compact PCI-Bus 8 Slots

LAN 1

LANto/from host computer,development system,remote service (option),PLC

SM CPU6

spare

VGA

spare 2*CANbusinterface

ES CAN/331

120/230 V~

CPCI-Power Supply

spare digital &analog

I/O

AD CPCI-3120-84

testoutputs

encoders

Encoder-Interface(SSI)

AD 1710

IRIG-Btime codereader

DT bc635

IRIG-Bsignal

LAN 2

analog velocity commands

(if required)

otherControl Panels

(optional)




6HU-Version of ACU 8100

4HU-Versionof ACU 8100



New Antenna Control Unit 8100 (6 HU)



Sample Local User Interface



Advantages of Suggested Approach Limited scope of upgrade

computer replacement only “budget-friendly” solution

Re-Use of components drive cabinet, PLC and servo

amplifiers encoders motors

Low risk the working interlock system and

low level control will be re-used return to existing system can easily

be achieved use of well proven components limited software effort

Limited software effort PLC software

• can be re-used to large extent• various functions not used any

more Servo computer software

• functionality already existing • only adaptations required for

Arecibo (interfaces, specific interlocks etc.)

Limited telescope downtime Estimated total downtime approx.

2-3 weeks With a little more effort, it would

even be possible to return to operation every night



Possibilities for Future Upgrades

Fully Digital Drive System very flexible control loop

structure improved performance much easier to be tuned than

analog DCS insensitive to EMI etc. less components …less failures … more software measurement of commands to

servo amplifiers is difficult and requires analyzers or test outputs in the computer (even more software…)

Adaptation to new host computer(s)

Extended operating modes Drive cabinet or servo

amplifiers only Motors ?



Fully Digital Servo System Overview

Servo Amplifier

local bus

EnDat or SSI

IRIG-B Time Code

Interlock System

Low LevelOperation

PLC

LAN

Antenna ControlUnit

seria

l

ACU

GearBox

limit switches etc.

Sensor

Motor

BS02238.SKF/07.02.2003

Antenna

several units positionfeedback

to/from host computer, software development,remote service option, etc.

LANRS232



Fully Digital Drive System

Position and velocity loops closed in servo computer Servo computer provides torque command to each motor via

local bus In low level control the servo amplifiers receive analog

commands Configuration of servo amplifiers is controlled by PLC via digital

inputs to amplifiers Existing drive motors could be kept Servo amplifiers (or entire drive cabinet) needs to be replaced Analog DCS could

… be kept for low level control … be removed, leading to a much simpler but “less comfortable” drive

concept in low level control



Fu l ly Digi tal Contr ol System

M: Mot orP: Pinion

G: Gear box

W: Wheel

E: Encoder



G

G

El

Dri

ve

Syste

min

cl.

CH

#1

Dri

ve

S

yste

m

D:\PROJ\AKTUELL\BS_Arecibo_FD.SKF/2004-05-24

P

1x GD + 1x CH

2x

E

E

G

M G

Az

Dri

ve

Syste

m

W

W


New Components



M

M

M


FO


DCS

setp

oint

s

TTY

moni

tori

ng &

con

trol

Main CPU

DCS

SSIdoubler

SSIdoubler

Mot orCont r oller#2t o host comput er

moni

tori

ng &

con

trol


PLC

IRIG- B

LAN

LAN

CP524

Oper at ion by t ouch scr eenor keyboar d & mouse

(in main cont r ol r oom)

FO

Ant ennaCont r ol Unit

LocalUserInt er f ace

CP524

Oper at ion Cont r olUnit (OCU)

LAN

RS232LAN


ACU

arecibo telescope servo & drive system - 1 - technical meeting may 2004 vertex antennentechnik...

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