VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 1
VST
VLT SURVEY TELESCOPE
DISTRIBUTED CONTROL SYSTEMS
DESIGN SPECIFICATIONS
Doc. No.: VST-SPE-OAC-24000-1029
Issue: 1.0
Pages: 21
Date: 09.11.00
File Name: VST-SPE-OAC-24000-1029-1.0
Activity
Names
System analysis, functionalities & Document design
Contents by
Document Preparation
Document Supervision & Check
Task Management
Documentation and Quality Control Manager
Task Responsibility
D.Mancini, C.Molfese
D.Mancini, C.Molfese
D.Mancini, C.Molfese
D.Mancini, V.Fiume Garelli
D.Mancini
V. Fiume Garelli
D.Mancini
mancini@na.astro.it
Questions and Remarks on contents
C.Molfese – molfese@na.astro.it – phone:+39 081
5575557 – fax: +39 081456710
Signature
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 2
CHANGE RECORD
Issue
Date
1.0
09.11.2000
Section/Paragrafh Affected
Reason/Initiation/Documents/Remarks
First release
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 3
TABLE OF CONTENTS
1
INTRODUCTION ........................................................................................................................................ 5
1.1
1.2
1.3
1.4
1.5
1.6
2
PURPOSE .............................................................................................................................................. 5
SCOPE .................................................................................................................................................. 5
DOCUMENT STRUCTURE DESIGN............................................................................................................ 5
REFERENCE DOCUMENTS ...................................................................................................................... 5
APPLICABLE DOCUMENTS ...................................................................................................................... 5
ABBREVIATIONS AND ACRONYMS ............................................................................................................ 5
GENERAL DESCRIPTION ........................................................................................................................ 7
3 CUSTOM MODULE DEVELOPMENT AND RELATED MICROCONTROLLER PLATFORM
SELECTION ................................................................................................................................................. 9
4
CANBUS#1 DESIGN SPECIFICATION .................................................................................................. 11
4.1
DESCRIPTION ...................................................................................................................................... 11
4.2
FUNCTIONAL REQUIREMENTS ............................................................................................................... 12
4.2.1
CAN Bus Interface Board ........................................................................................................... 12
4.2.2
Motor Cooling Controller ............................................................................................................ 12
4.2.3
Temperature Acquisition Module ............................................................................................... 12
4.3
PERFORMANCE REQUIREMENTS ........................................................................................................... 13
4.3.1
CAN Bus Interface Board ........................................................................................................... 13
4.3.2
Motor Cooling Controller ............................................................................................................ 13
4.3.3
Temperature Acquisition Module ............................................................................................... 13
5
CANBUS#2 DESIGN SPECIFICATION .................................................................................................. 14
5.1
DESCRIPTION ...................................................................................................................................... 14
5.2
FUNCTIONAL REQUIREMENTS ............................................................................................................... 15
5.2.1
CAN Bus Interface Board ........................................................................................................... 15
5.2.2
Motor Cooling Controller ............................................................................................................ 15
5.2.3
Temperature Acquisition Module ............................................................................................... 15
5.3
PERFORMANCE REQUIREMENTS ........................................................................................................... 15
5.3.1
CAN Bus Interface Board ........................................................................................................... 15
5.3.2
Motor Cooling Controller ............................................................................................................ 15
5.3.3
Temperature Acquisition Module ............................................................................................... 15
6
CANBUS#3 DESIGN SPECIFICATION .................................................................................................. 16
6.1
DESCRIPTION ...................................................................................................................................... 16
6.2
FUNCTIONAL REQUIREMENTS ............................................................................................................... 16
6.2.1
CAN Bus Interface Board ........................................................................................................... 16
6.2.2
Astatic Lever Controller .............................................................................................................. 16
6.3
PERFORMANCE REQUIREMENTS ........................................................................................................... 17
6.3.1
CAN Bus Interface Board ........................................................................................................... 17
6.3.2
Astatic Lever Controller .............................................................................................................. 17
7
CANBUS#4 DESIGN SPECIFICATION .................................................................................................. 18
7.1
7.2
DESCRIPTION ...................................................................................................................................... 18
FUNCTIONAL REQUIREMENTS ............................................................................................................... 19
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 4
7.2.1
CAN Bus Interface Board ........................................................................................................... 19
7.2.2
Motor Cooling Controller ............................................................................................................ 19
7.2.3
Temperature Acquisition Module ............................................................................................... 19
7.3
PERFORMANCE REQUIREMENTS ........................................................................................................... 19
7.3.1
CAN Bus Interface Board ........................................................................................................... 19
7.3.2
Motor Cooling Controller ............................................................................................................ 19
7.3.3
Temperature Acquisition Module ............................................................................................... 19
8
HARDWARE COMPONENTS DESIGN SPECIFICATIONS ................................................................... 20
8.1
8.2
8.3
8.4
CAN BUS I/F BOARD ........................................................................................................................... 20
ASTATIC LEVER CONTROLLER .............................................................................................................. 21
MOTOR COOLING CONTROLLER ........................................................................................................... 21
TEMPERATURE ACQUISITION MODULE .................................................................................................. 21
TABLES & FIGURES
Fig. 3.1 - Microcontrolled Module for CANBus General Architecture .............................................................. 10
Fig. 4.1 - CANBUS#1 Configuration ................................................................................................................ 11
Fig. 5.1 - CANBUS#2 Configuration ................................................................................................................ 14
Fig. 6.1 - CANBUS#3 Configuration ................................................................................................................ 16
Fig. 7.1 - CANBUS#4 Configuration ................................................................................................................ 18
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 5
1
INTRODUCTION
1.1 PURPOSE
This document reports the design specification of the distributed control systems based on CAN Bus that are
envisaged for the VST. The document is to be intended as a guideline for hardware detailed design and
development.
1.2 SCOPE
This Document is applicable to the development of VST Telescope distributed control systems based on
CAN Bus.
1.3 DOCUMENT STRUCTURE DESIGN
In the first part of the document a general description of distributed control systems envisaged for VST
Telescope is given. Information about custom development activities and microcontroller platform selection
are in chapter 3. Description of each CAN Bus Control System and of its functional and performance
requirements are indicated in the document. Design specifications of commercial and custom module are
given in the chapter 8.
1.4 REFERENCE DOCUMENTS
[1] VST-TRE-OAC-24000-1008, VST Control Hardware
1.5 APPLICABLE DOCUMENTS
[1] VLT-INS-ESO-01000-0001, Directive for Preparation of Technical Specifications
[2] VLT-SPE-ESO-11410-0674, Technical Specification for the Opto-Mechanical Parts of the Cassegrain
Adapter-Rotators for the Very Large Telescope
[3] VLT-SPE-ESO-10000-0006, VLT Observatory Requirements for Nasmyth Instruments
[4] VLT-SPE-ESO-10000-0017, General Safety – Requirements for Scientific Instruments
[5] VLT-TRE-ESO-00000-0001, VLT Maintenance Concept
[6] VLT-TRE-ESO-00000-0467, Requirements for Safety Analyses
1.6 ABBREVIATIONS AND ACRONYMS
A/D
ADC
ADP
APCS
Analog-to-Digital conversion
Atmospheric Dispersion Corrector
Adapter
Axial and Radial Pads Control System
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 6
AZ
Azimuth
CAB#x Cabinet n.x
CIR
Central Intensity Ratio
CORR Corrector
D/A
Digital-to-Analog conversion
DER Derotator
DMA Direct Memory Access
EL
Elevation
EMIF Electro-Magnetic Interference Filter
ESO European Southern Observatory
FEA
Finite Element Analysis
FEE
Front End Electronics
GESS General Emergency Stop System
HBS
Hydrostatic Bearing System
HPCS Hexapod Positioning Control System
LCU
Local Control Unit
LESS Local Emergency Stop System
LSB
Lowest Significant Bit
LUT
Look Up Table
OAC Osservatorio Astronomico di Capodimonte
PHA
Preliminary Hazard Analysis
PHL
Preliminary Hazard List
PI
Proportional-Integrative Controller
RMS Root Mean Square
SCP
Service Connection Point
SHA
Sub-System Hazard Analysis
TBC
To Be Confirmed
TBD
To Be Defined
TBU
To Be Updated
TCS
Telescope Control Software
TWG Technology Working Group
UD
Under Definition
VLT
Very Large Telescope
VST
VLT Survey Telescope
VME Versa Module Eurocard
WS
WorkStation
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 7
2 GENERAL DESCRIPTION
For the VST Telescope four distributed control systems, driven through CAN Busses, are envisaged for the
control/acquisition of the following aspects:
 M1 Axial and Radial Pads control
 Motors cooling system and temperature acquisition
 Telescope structure temperature acquisition
The CAN Busses and the related control functions are here listed:
CANBUS#1: AZ Motors cooling system, AZ Motors temperature acquisition, AZ structure temperature
acquisition (connected to LCU#1)
CANBUS#2: ALT Motors cooling system, ALT Motors temperature acquisition, AZ structure temperature
acquisition (connected to LCU#2)
CANBUS#3: M1 Axial and Radial Pads control (connected to LCU#3)
CANBUS#4: ROT Motors cooling system, ROT Motors temperature acquisition, ALT structure temperature
acquisition (connected to LCU#3)
Each CAN Bus will be connected to one LCU by means of TEWS DATENTECHNIK TPMC816 2 Channel
CAN Bus PMC Module as recommended by ESO. This module is suitable to be fitted into the PCI Mezzanine
socket available on the Motorola VME 2604 CPU Card, envisaged for the LCUs.
The availability of driver S/W ESO for the integration of this module into the Motorola CPU Card is being
checked.
Another solution to connect the CAN Bus with LCUs is based on the VME-CAN4 Intelligent CAN Bus I/F
Board for VME Bus, manufactured by ESD; the S/W development support for this card is based on standard
VxWorks drivers, but no ESO drivers should be available.
Both commercial items are suitable to implement the CAN Bus I/F Board, but the former should be preferred,
because better software supported.
The features of the TPMC816 module and the ones of the VME-CAN4 board are reported in 8.1.
The integration of the CAN Bus I/F into the LCU (PMC Module or VME Card) has been preferred to the one
based on CAN Bus I/F modules connecting CAN Bus to RS-232 serial Interface, as described in [1], for the
following two reasons:


More powerful: this solution allows to exploit the whole transmission rate available with the CAN Bus (1
Mbit/s; this through-put value is much greater than the one actually requested by the application).
More compact and easy to be integrated
This board will be the master of the single CANBus network and can address the slaves modules to send
configuration parameters or to request data. The address mechanism is based on the acceptance filtering
capability. All CAN implementations provide some hardware acceptance filters to relieve the microcontroller
from the task of filtering those messages which are needed from those which are not of interest.
The address space managed by the acceptance filter is equal to 127 devices (sufficient for VST application),
but it can also be expanded allocating one or more bytes of the data field of the CANBus standard packet as
auxiliary address. This theoretical number of devices can be connected at the same time is derived by the
CAN Bus data link protocol, but is also limited by the drive capability of the electronic device; so line drivers
are to be selected carefully. Furthermore the use of signal repeater will be evaluated if necessary.
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 8
The physical layer is based on a twisted pair for data transmission; two other wires are present to distribute
12Vdc power to all modules connected to the network. The maximum data rate envisaged for the CANBus is
equal to 1 Mbit/s.
The power supply for the electronics envisaged for the modules will be provided by the CAN Bus; one DCDC converter for each module will perform +12/+5 [V] conversion. The power supply for all the actuators,
sensors and the electronics connected after the insulation barrier will be distributed by a Field Power Bus.
On the CAN Bus the connection of the three kinds of modules is envisaged:
 108 Astatic Lever Controller (CAN Bus#3)
 10 Motor Cooling Controller (CAN Bus#1-2-4)
 20 (TBC) Temperature Acquisition Module (CAN Bus#1-2-4)
All the mentioned modules will be provided with microcontroller for communication protocol management
and to control the hardware devices present on the module. From the LCU, via serial I/F and CAN Bus, the
functioning parameters are communicated to one module; then the module will implement the closed loop
control locally without other intervention of the LCUs.
The Astatic Lever Controller and the Motor Cooling Controller will be custom developed as indicated in point
3 of the document.
The Temperature Acquisition Module will be implemented by means of commercial solution based on the
CAN-CPT100/4 four analog thermal input module, manufactured by ESD; whose characteristics are reported
in 8.4.
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 9
3 CUSTOM
MODULE DEVELOPMENT AND RELATED MICROCONTROLLER
PLATFORM SELECTION
To implement the Astatic Lever Controllers and Motor Cooling Controllers, the development of application
specific solution is an obliged choice, because no commercial solution able to fulfill completely the
application requirements is available.
A semi-custom solution based on commercial modules providing connection between CAN Bus and
standard analog input/output, together with a minimum of custom electronics for field sensors/actuators
connection, leads to a very expensive solution with a low level of integration; this can be critical especially for
the implementation of the Astatic Lever Controllers, due to the large number of this kind of modules and due
to the limited room available for their accommodation under the primary mirror.
The microcontroller platform selected to implement the custom modules is the PIC controller by Microchip.
The PIC has been preferred to other commercial platform, such as Siemens, Hitachi, ST Microlectronics for
the following reasons:
 It is better suited for custom developments with low number of pieces to be manufactured
 The people of OAC involved in the development activities already know the use of PIC
 It is well supported by development kit for CAN Bus application, using the MCP2510 CAN Bus
Communication Controller
The following aspects are very effective in terms of reduction of time/risks of the project
The following PIC development tools will be employed:
- Programmer: PICSTART PLUS or PROMATE II
- Emulator: MPLAB-ICE or equivalent
- MCP2510 Can Development’s kit, providing both S/W support libraries and CAN I/F evaluation board
- In-circuit debugger: MPLAB-ICD
- ANSI C Compiler by third party such as CCS, Hi-tech and IAR
The PIC component family chosen for the application is the 16F87x, a flash memory microcontroller
providing program memory that ranges from 2k to 8k bytes. This component with flash memory will be
employed during the development activities because it allows fast programming time (no erasing process is
needed) and it allows also the use of the in-circuit debugger; both aspects are speeding up the development
time.
For the implementation of the final version of the firmware, the 16C6x microcontrollers OTP (one time
programmable) family, equivalent to the flash one, will be employed; this components are cost effective and
more reliable, concerning memory erasing problems.
All the firmware will be written in ANSI C language.
OAC TWG will be in charge of the custom modules design and prototype manufacturing. All aspects of
functionality, concerning also reliability and EMI/EMC, will be tested before the production of all module
electronic boards.
The manufacturing will be carried out by specialized companies by means of automatic pick-and-place
machines; automatic electrical test, aimed at verifying the mounting and soldering problems, and manual
functional tests will be finally performed.
The manufactured modules will include a sufficient number of spare module for the maintenance of the
subsystems.
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 10
A general architecture diagram of a microcontrolled module for CAN Bus is depicted in the picture Fig. 3.1.
The microcontroller is the PIC 16C6x (16F87x for development activities only) by Microchip. It has integrated
inside ALU, ROM for firmware storage and RAM for program execution.
The CAN Bus Communication Controller for protocol management is the MCP2510 by Microchip,
implementing full CAN 2.0 A and B, at 1 Mbit/s of transmission rate.
The following components are also present on the module: CANBus and RS-232 line drivers; optoisolated
driver for motors or electrovalves activation; optoisolated serial ADC and conditioning electronics to interface
external analog sensors, such as temperature sensors and load cells.
CANBus Power Lines
CANBus Data Lines
+12V.
GND
RS-232
Line drivers
and Receiver
DC/DC
Converter
CAN Bus
Line drivers
and Receiver
MCP2510 CAN
Communication
Controller
+5V.
PIC 16C6x (16F87x)
Microcontroller
Serial
Comm.
Controller
ROM
ALU
RAM
I/O Ports
from Field
Power BUS
Optoisolated DAC
and
Power Drivers
Optoisolated
ADC and
Conditioning
Electronics
To
Electromechanical
Devices
From Sensors
(Temperature sensors;
Load cells)
Fig. 3.1 – Microcontrolled Module for CANBus General Architecture
PICmicro MCU Overview (Note by Microchip)
Microchip PICmicro MCUs combine high-performance, low-cost, and small package size, offering the best
price/performance ratio in the industry. More than 120 million of these devices ship each year to costsensitive consumer products, computer peripherals, office automation, automotive control systems, security
and telecommunication applications.
Microchip offers four families of 8-bit MCUs to best fit your needs: PIC16C5X 12-bit program word,
PIC16CXXX 14-bit program word, PIC17CXXX 16-bit program word, PIC18CXXX enhanced 16-bit program
word and PIC12CXXX 8-pin 12-bit/14-bit program word MCU families.
All families offer OTP, low-voltage and low-power options, with a variety of package options. Selected
members are available in ROM, EEPROM or reprogrammable Flash versions.
The widely-accepted PIC16C5X, PIC16CXXX and PIC17CXXX MCU families employ a modified RISC
architecture. Microchip pioneered the use of RISC architecture to obtain high speed and instruction
efficiency.
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 11
4 CANBUS#1 DESIGN SPECIFICATION
4.1 DESCRIPTION
The CANBUS#1 will be connected to LCU#1 and will have to perform the following tasks:
 AZ Motors cooling system
 AZ Motors temperature acquisition
 AZ structure temperature acquisition
The CANBUS#1 configuration will be based on the following items:
 CAN Bus I/F Board
 Motor Cooling Controller (performing motor temperature acquisition as well)
 Temperature Acquisition Module
The CANBUS#1 configuration is represented in Fig. 4.1.
CAN Bus
I/F
Board
CAN Bus
Motor Cooling
Controller
Motor Cooling
Controller
Motor Cooling
Controller
Motor Cooling
Controller
LCU#1
Electro
valve
In
Out1
...
Electro
valve
Temperature
sensors
Out2
In
Out1
...
In
Out2
...
Electro
valve
Temperature
sensors
Out1
Electro
valve
Temperature
sensors
Out2
In
CAN Bus
Temperature
Acquisition
Module
...
Temperature
sensors
Fig. 4.1 - CANBUS#1 Configuration
Temperature
Acquisition
Module
Temperature
sensors
Out1
...
Temperature
sensors
Out2
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 12
4.2 FUNCTIONAL REQUIREMENTS
4.2.1 CAN Bus Interface Board
The functional requirements to be fulfilled by the CAN Bus I/F Board are the following:
 Implementation of one CAN interface
 Implementation of the physical and data link layer according to the ISO 11898
 Implementation of the data link layer according to the CAN 2.0 B standard
 Addressing capability, as unique master of the network, to communicate with all connected CAN nodes,
to send configuration parameter and to acquire data and status information
 Galvanic insulation of the CAN from LCU, by means of opto-couplers and insulated DC-DC Converters
4.2.2 Motor Cooling Controller
The Motor Cooling Controller is devoted to implement the closed loop control of the temperature of the main
axes and rotator motors. The temperature are acquired from several sensors by means ADC and
conditioning electronics present on the module. The cooling liquid flow is controlled with an electrovalve
powered by an electronic driver. More details about the motor cooling system are given [1].
Each controller will be based on the following components:
 Microcontroller
 CAN Bus Communication controller
 CAN Bus Interface drivers
 ADC and conditioning electronics for temperature sensors
 Optoinsulated Electrovalve driver
 RS-232 serial port for monitoring and debugging functions
The functional requirements to be fulfilled by the Motor Cooling Controller are the following:
 Control of the cooling liquid electrovalve by means of linear regulator firmware implemented
 Acquisition of temperatures from the sensors
 Implementation of the physical and data link layer according to the ISO 11898
 Implementation of the data link layer according to the CAN 2.0 B standard
 Implementation of monitoring and debugging functions via CAN Bus and local RS-232 serial port
 Galvanic insulation of electrovalve and sensors, by means of opto-couplers and insulated DC-DC
Converters
4.2.3 Temperature Acquisition Module
The Temperature Acquisition Module is aimed at telescope temperature acquisition. The following main
components will be present on this module:
 Microcontroller
 CAN Bus Communication controller
 CAN Bus Interface drivers
 ADC and conditioning electronics for temperature sensors
 RS-232 serial port for monitoring and debugging functions
The functional requirements to be fulfilled by the Temperature Acquisition Module are the following:
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 13





Acquisition of temperatures from sensors
Implementation of the physical and data link layer according to the ISO 11898
Implementation of the data link layer according to the CAN 2.0 B standard
Implementation of monitoring and debugging functions via CAN Bus and local RS-232 serial port
Galvanic insulation of sensors, by means of opto-couplers and insulated DC-DC Converters
4.3 PERFORMANCE REQUIREMENTS
4.3.1 CAN Bus Interface Board
The performance requirements to be fulfilled by the CAN Bus I/F Board are the following:
 Data rate: 1 Mbit/s
 Power supply provided to the CAN interface: +12 V.
4.3.2 Motor Cooling Controller
Electrovalve type to be controlled: TBD; maximum requested flow rate: 12 [l/min]
Electrovalve electrical characteristics:
 Power Supply voltage: 24[Vdc]
 Maximum current: TBD
Temperature sensors type: PT100 mod: TBD
Temperature acquisition performances:
 Temperature range: from –15 to +50 [°C]
 Overall Accuracy: +/- 0.1 [°C]
 Electrical I/F: 4-wires connection
Temperature control accuracy: better than +/-1.5 [°C]
4.3.3 Temperature Acquisition Module
Temperature sensors type: PT100 mod: TBD
Temperature acquisition performances:
 Temperature range: from –10 to +30 [°C]
 Overall Accuracy: +/-0.1 [°C]
 Electrical I/F: 4-wires connection
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 14
5 CANBUS#2 DESIGN SPECIFICATION
5.1 DESCRIPTION
The CANBUS#2 will be connected to LCU#2 and will have to perform the following tasks:
 ALT Motors cooling system
 ALT Motors temperature acquisition
 AZ structure temperature acquisition
The CANBUS#2 configuration will be based on the following items:
 CAN Bus I/F Board
 Motor Cooling Controller (performing motor temperature acquisition as well)
 Temperature Acquisition Module
The CANBUS#2 configuration is represented in Fig. 5.1.
CAN Bus
I/F
Board
CAN Bus
Motor Cooling
Controller
Motor Cooling
Controller
Motor Cooling
Controller
Motor Cooling
Controller
LCU#2
Electro
valve
In
Out1
...
Electro
valve
Temperature
sensors
Out2
In
Out1
...
Electro
valve
Temperature
sensors
In
Out2
Out1
...
Electro
valve
Temperature
sensors
In
Out2
CAN Bus
Temperature
Acquisition
Module
Temperature
sensors
...
Temperature
Acquisition
Module
Temperature
sensors
Fig. 5.1 - CANBUS#2 Configuration
Out1
...
Temperature
sensors
Out2
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 15
5.2 FUNCTIONAL REQUIREMENTS
5.2.1 CAN Bus Interface Board
See paragraph 4.2.1.
5.2.2 Motor Cooling Controller
See paragraph 4.2.2.
5.2.3 Temperature Acquisition Module
See paragraph 4.2.3.
5.3 PERFORMANCE REQUIREMENTS
5.3.1 CAN Bus Interface Board
See paragraph 4.3.1.
5.3.2 Motor Cooling Controller
See paragraph 4.3.2.
5.3.3 Temperature Acquisition Module
See paragraph 4.3.3.
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 16
6 CANBUS#3 DESIGN SPECIFICATION
6.1 DESCRIPTION
The CANBUS#3 will be connected to LCU#3 and will have to perform the following tasks:
 M1 Axial and Radial Pads control
The CANBUS#3 configuration will be based on the following items:
 CAN Bus I/F Board
 Astatic Lever Controller
The CANBUS#3 configuration is represented in Fig. 6.1.
CAN Bus
I/F
Board
CAN Bus
Field
Power Bus
Astatic Lever
Controller #1
Field
Power Bus
Astatic Lever
Controller #1
....
LCU#3
R
L
Load
Limit
Cell
DC Motor
sw itches
and Tacho
M1 Axial
and Radial
Pads
R
L
Load
Limit
Cell
DC Motor
sw itches
and Tacho
Fig. 6.1 - CANBUS#3 Configuration
6.2 FUNCTIONAL REQUIREMENTS
6.2.1 CAN Bus Interface Board
See paragraph 4.2.1. Two CAN I/F have to be provided.
6.2.2 Astatic Lever Controller
The Astatic Lever Controller is devoted to the Astatic Pad DC Motor control; it will be based on:
 Microcontroller
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 17







CAN Bus Communication controller
CAN Bus Interface drivers
Opto-insulated Load Cell Interface
Opto-insulated Tachometer Interface
Opto-insulated DC Motor Driver
Software Limit Switches interface
RS-232 serial port for monitoring and debugging functions
The functional requirements to be fulfilled by the Astatic Lever Controller are the following:
 Control of the applied force by means of linear regulator
 Control of the DC motor
 Acquisition of force from the load cell
 Acquisition of the end-switches status
 Acquisition of motor speed from the tachometer
 Implementation of the physical and data link layer according to the ISO 11898
 Implementation of the data link layer according to the CAN 2.0 B standard
 Implementation of monitoring and debugging functions via CAN Bus and local RS-232 serial port
 Galvanic insulation of motor and sensors, by means of opto-couplers and insulated DC-DC Converters
 Provide electrical connection for Axial Pad Magnetic Blocker
6.3 PERFORMANCE REQUIREMENTS
6.3.1 CAN Bus Interface Board
See paragraph 4.3.1.
6.3.2 Astatic Lever Controller
DC Motor type to be controlled: FAULHABER DC MINIMOTOR mod.1841 16/5 1596:1
DC Motor electrical characteristics:
 Power Supply voltage: 24 [Vdc]
 Maximum Current: 300 [mA]
Load Cell sensors type: LEBOW mod.3167-500
Force acquisition performances:
 Force range: 0-500 [N] TBC
 Overall Accuracy: TBD
 Max excitation voltage: 20 [Vdc] or 20 [Vac rms]
 Bridge nominal resistance: 350 [Ohm]
 Output at rated capacity: 2 [mV per V]
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 18
7 CANBUS#4 DESIGN SPECIFICATION
7.1 DESCRIPTION
The CANBUS#4 will be connected to LCU#3 and will have to perform the following tasks:
 ROT Motors cooling system
 ROT Motors temperature acquisition
 ALT structure temperature acquisition
The CANBUS#4 configuration will be based on the following items:
 CAN Bus I/F Board
 Motor Cooling Controller (performing motor temperature acquisition as well)
 Temperature Acquisition Module
The CANBUS#4 configuration is represented in Fig. 7.1.
CAN Bus
I/F
Board
CAN Bus
ROT Motor1
Cooling
Controller
LCU#3
Electro
valve
In
Out1
ROT Motor 2
Cooling
Controller
...
Electro
valve
Temperature
sensors
Out2
In
Out1
Temperature
Acquisition
Module
...
Temperature
Acquisition
Module
...
Temperature
sensors
Temperature
sensors
Out2
Fig. 7.1 - CANBUS#4 Configuration
Temperature
sensors
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 19
7.2 FUNCTIONAL REQUIREMENTS
7.2.1 CAN Bus Interface Board
See paragraph 4.2.1. Two CAN I/F have to be provided.
7.2.2 Motor Cooling Controller
See paragraph 4.2.2.
7.2.3 Temperature Acquisition Module
See paragraph 4.2.3.
7.3 PERFORMANCE REQUIREMENTS
7.3.1 CAN Bus Interface Board
See paragraph 4.3.1.
7.3.2 Motor Cooling Controller
See paragraph 4.3.2.
7.3.3 Temperature Acquisition Module
See paragraph 4.3.3.
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 20
8 HARDWARE COMPONENTS DESIGN SPECIFICATIONS
8.1 CAN BUS I/F BOARD
In this paragraph the features of TEWS DATENTECHNIK TPMC816 2 Channels CAN Bus PMC Module and
the ESD VME-CAN4 Intelligent CAN Bus I/F Board for VME Bus are reported.
TEWS DATENTECHNIK TPMC816 2 Channels CAN Bus PMC Module
Features
- Standard single-width 32-bit PMC module conforming to IEEE P 1386.1
- PCI 2.1 compliant interface
- CAN Bus I/F based on Intel 82527 chipset
- Supporting CAN Specification 2.0 part A and B
- Max tranfer rate equal to 1 Mbit/s
- Phisical interface CAN High Speed (according to ISO 11898) and modified RS485 per channel
- Phisical I/F optically insulated from CAN Controller by onboard DC/DC converter per channel
OS support
-VxWorks
-pSOS
-OS-9
ESD VME-CAN4 Intelligent CAN Bus I/F Board for VME Bus.
Intelligent CAN Controllers
- Full CAN controller by integrated firmware for any identifier
- Each channel with separate micro controller (68331/20Mhz) and its own CAN controller (SAJ1000)
- Lossless data exchange with VMEbus via Shared RAM and FIFOs
CAN Layer
- CAN layer according to ISO 11898 with 9-pole DSUBs or DeviceNet interface
- Data transfer rate up to 1 Mbit/s
- Each channel electrically isolated by optocouplers
CAN Protocol Support
- CAL/CMS and CANopen
- DeviceNet
- SDS Smart Distributed System
- Multi-Net support
OS support
-VxWorks
-LynxOS
-OS-9
-UNIX
VST Project
Technology Working Group
Osservatorio Astronomico di Capodimonte Napoli
Date: 09.11.2000
Page: 21
8.2 ASTATIC LEVER CONTROLLER
The Astatic Lever Controller is devoted to the Astatic Pad DC Motor control; it will be custom developed and
based on:
 Microcontroller for communication with CAN Bus
 CAN Bus Interface drivers
 Opto-insulated Load Cell Interface
 Opto-insulated Tachometer Interface
 Opto-insulated DC Motor Driver
 Software Limit Switches interface
 RS-232 serial port for monitoring and debugging functions
Two limit switches will be provided. The Limit Switches are read out by the microcontroller and are used to
avoid out of range actuator movement.
8.3 MOTOR COOLING CONTROLLER
The Motor Cooling Controller will be custom developed and devoted to implement the closed loop control of
the temperature of the main axes and rotator motors. The temperature are acquired from several sensors by
means ADC and conditioning electronics present on the module. The cooling liquid flow is controlled with an
electrovalve powered by an electronic driver.
Each controller will be based on the following components:
 Microcontroller for communication with CAN Bus
 CAN Bus Interface drivers
 ADC and conditioning electronics for temperature sensors
 Optoinsulated Electrovalve driver
 RS-232 serial port for monitoring and debugging functions
8.4 TEMPERATURE ACQUISITION MODULE
In this paragraph the features of ESD CAN-CPT100/4 module implementing the Temperature Acquisition
Module are described.
-
Num. of input sensors: 4
Sensors type: PT100
A/D Converter resolution: 12 bits
Linearity error: +/- 1 LSB
Max sampling rate: 2.5 kHz/channel
Module operating voltage: 24 [Vdc]
CAN Layer ISO 11898, 1 Mbit/s