Introduction to the Astrometric Telescope Control System
Contents
1. User s Manual and set up SkyGuide per the instructions in chapter 4 of that document Testing 1 Verify that SkyWalker1 s Sys SW switch is in the Sys i e System mode position 2 Turn on SkyWalker1 3 Turn on the servo drivers Note the FAULT LEDs will light for 5 to 10 seconds and then should go out Start SkyGuide on the PC Enter Land mode From the handpaddle try left right up down to verify view motion Oe oe e Enter slew mode Slew button on handpaddle and try left right up down to verify slew motion 11 Introduction to the Astrometric Telescope Control System for SkyWalker1li on Custom Telescope Mounts Installation is complete 12 Congratulations SkyWalker1i installation is now complete If ATCS is to be used in SkyWalker mode then proceed to read the Operation in Sky Walker mode section of the SkyWalkerl Owner s Manual If ATCS is to be used in System mode then be sure to read at least chapter 1 Introduction chapter 2 Getting Started with SkyGuide and chapter 3 Start up Settings in the SkyGuide User s Manual Note System mode operation is a superset of SkyWalker mode operation therefore the SkyGuide User s Manual supercedes all operational information in the SkyWalkerl Owner s Manual2. Introduction to the Astrometric Telescope Control System For SkyWalkerli on Custom Telescope Mounts Copyright 2002 Astrometric Instruments Inc last revision date 16 Oct 2002 Please read this document first This document can be ordered as Astrometric Instruments part DOC 03E Introduction to the Astrometric Telescope Control System for SkyWalker1li on Custom Telescope Mounts Introduction to the Astrometric Telescope Control System for SkyWalker1li on Custom Telescope Mounts Introduction This document provides an introduction to and installation instructions for the Astrometric Telescope Control System ATCS on custom telescope mounts The version of ATCS covered in this document is our SkyWalkerli product SkyWalker1i is an integrated telescope control system based on our SkyWalkerl Telescope Motor and Accessory Controller The contents of this document are as follows This introduction Brief overview of ATCS components and function SkyWalker11 installation instructions Much additional detail on the operation of ATCS is provided in the following two documents 1 SkyGuide User s Manual 2 SkyWalkerl Owner s Manual There are several important steps in installing the SkyWalkerli system components and important notes on using ATCS These are highlighted in this document as follows Important Please read important notes The user should be very careful to read understand and follow these import
3. ant notes Otherwise sub par operation or even damage to your hardware can result Two important definitions are needed at this point SkyWalker mode when ATCS is being used without an attached PC it is being used in Sky Walker mode System mode when ATCS is being used with a Windows 95 98 ME PC running our SkyGuide telescope control system software it is being used in System mode The specifics of SkyWalker mode and System mode are provided in the next section If ATCS is to be used in SkyWalker mode then read the SkyWalker Owner s Manual next There is no need to read the SkyWalker Owner s Manual if ATCS is not used in SkyWalker mode since all typical SkyWalker1 installation details and setup are provided in this document Important If ATCS is to be used in System mode then be sure to read at least Chapter 1 Introduction and Chapter 2 Running SkyGuide for the first time in the SkyGuide User s Manual Introduction to the Astrometric Telescope Control System for SkyWalker1li on Custom Telescope Mounts Brief overview of ATCS components and function ATCS allows for controlling all operations of a telescope system The current version of ATCS has evolved from over a decade of development and use of telescope control systems We believe that it is the most capable telescope control system available to amateurs today We have taken great effort to include useful features and us
4. er friendly interface to these features Additionally dedicated and patient beta testers have used ATCS throughout its development We are indebted to these folks The major components of ATCS are briefly described in this section More and up to date detail can be found at our web site www astrometric com SkyWalker and SkyGuide The hub of Astrometric Instruments Telescope Control System ATCS is the SkyWalker Telescope Motor and Accessory Controller Together with its handpaddle SkyWalker is a standalone telescope controller or when used with a PC running our SkyGuide Telescope Control System software a complete and full featured telescope control system ATCS provides two levels of functionality SkyWalker mode and System mode In SkyWalker mode the control system operates without the need for an attached PC SkyWalker operates autonomously as a versatile telescope and accessory controller High speed slew four user selectable pan and slow motion rates and five tracking rates for equatorial mounts are supported Numerous telescope control functions electric focus control autoguider correction reticle illumination etc are also available SkyWalker mode requires a SkyWalker and high performance motors adapted to a telescope Astrometric Instruments provides the SkyWalkerli system that provides the motors power supplies and all the cabling necessary to use SkyWalker on custom telescope mounts SkyWalker mode doe
5. he servomotor and servo driver Refer to figure 1 for assistance with the following electrical connections Note be very careful since some servo driver text for example 18 TO 80 VDC and POWER GROUND will be partial obscured by the ASM If you purchased the servomotors and servo drivers at the same time then your system has been shipped with the connections between these components already made as an example of correct hook up You may wish to keep these initial connections or not depending on your installation details e g you may need to separate the motor driver for mounting Connect power to the servo driver Positive supply voltage red wire to 18 TO 80 VDC Ground black wire to POWER GROUND Note standard cabling shipped with this system provides a heavy 18guage connection through each cable i e the RA and Dec for power to the servo drivers The positive power lead is red or has a red band around it at the motor end The negative power lead is black at both ends If you are using an APS 150 or APS 230 power supply provided by Astrometric Instruments you simply need to plug the two connectors at the end of the cable one for servo driver power and the other for SkyWalkerl power into the matching receptacles on the power supply The SkyWalkerl power is a 2 5mm barrel connector and the servo driver power is a keyed CPC connector It is not possible to mis plugin the APS connectors If you are u
6. is the HardLimit pin and the other is signal ground A jumper is supplied installed across these pins to facilitate initial testing of the system Remove this jumper and install a HardLimit switch prior to operating the system post installation In the event of a HardLimit condition the red LED on the ASM will light When in HardLimit the motor drivers are inactive If the HardLimit condition cannot be cleared by manually moving the telescope out of HardLimit then the push button switch next to the HardLimit LED can be used to disable the HardLimit for as long as it is depressed Mount and make necessary connections to SkyWalker1 SkyWalker1 is provided with mounting holes 6 32 on the back of the enclosure It is very important that only nylon i e non conductive screws be used in these holes Conductive screws could short to SkyWalker1 s internal circuit board SkyWalkerl is shipped with two nylon screws installed in these holes Make the following connections to SkyWalker1 1 Connect 12 VDC to SkyWalker1 through its power cable into the Pwr port 2 Connect the RA and Dec motor cables into the RA and DEC ports 3 Connect the RS232 serial cable from the PC DB9 to SkyWalker1 Com port 4 Connect the HP1 handpaddle to the HP port 5 Connect optional optical encoder cable 8 pm modular plug with two 4wire cables into the Enc port 6 Install SkyGuide per the instructions in chapter 1 of the SkyGuide
7. n be dissipated If the motor is attached to a metal surface that will carry away the heat then the motor can be safely driven within the load limits set by the servo driver electronics Mount the servo driver on a metal preferably heat sinking surface near the servomotor The driver will not dissipate much power however it can get quite hot if not mounted on metal It is important to mount the servo driver so that it is protected from the elements For example it should never be allowed to have dew condense on it Servo driver functions The servo driver see figure 1 is composed of two components the actual 3 party servo driver electronics and Astrometric Instrument s Axial Support Module ASM Introduction to the Astrometric Telescope Control System for SkyWalkerli on Custom Telescope Mounts Figure 1 The servo driver is capable of delivering up to 20 amps to a brush type DC servomotor It accepts step and direction signals from SkyWalker which are forwarded through the ASM module for convenient modular plug connection The ASM provides the following functions e Modular jack connection for the cable from SkyWalkerl and for the optional GearIndex cable that allows for permanent gear periodic error correction A push button switch that allows the system to override a HardLimit condition This circuit also provides red LED indication of the HardLimit condition and a 2 pin 0 100 header for the HardLimit a
8. nd Ground connection Current limiting circuitry Servomotors typically have two current limits that are of importance a the maximum transient current that the motor can accept without damage to itself or its gearbox i e due to excessive torque and b the maximum current that the motor can accept continuously without overheating The servo driver contains circuitry that prevents violation of the transient rating The ASM module contains integrator circuitry that prevents violation of the continuous current rating If when the continuous current rating is exceeded the servo driver is reset for 5 seconds Motor load indication The orange LED will light when the motor load exceeds the threshold set by the continuous current integrator circuit mentioned in the previous Introduction to the Astrometric Telescope Control System for SkyWalkerli on Custom Telescope Mounts bullet Note the orange LED can flicker on or even light up nearly continuously without the continuous current limit circuitry resetting the drive This is normal behavior The orange LED is only an indication that the motor load is approaching the continuous integrator limit The limit will not be tripped without 10 to 20 seconds of high load Better annotation of the components of the ASM module is provided in figure 2 Gearlndex HighLoad HardLimit Current orange red input Ma HardLimit Override button R SkyWalker1 K HardLimit Reset outp
9. o be viewed with the free Adobe Acrobat Reader v4 0 or later Registered users can request PDF documentation files by sending an email request to support astrometric com or down load copies directly from our documentation support page www astrometric com support support_manuals html What do I do now After reading the next section on installing the SkyWalkerli system please proceed as follows 1 If use of ATCS in SkyWalker mode is planned then read the SkyWalkerl Owner s Manual It is anticipated that many installations will never use ATCS in SkyWalker mode In this case reading the SkyWalker Servo Owner s Manual is optional 2 Before using ATCS in System mode it is recommended that the SkyGuide User s Manual is read Since the SkyGuide User s Manual is rather voluminous and since you probably want to start using ATCS as soon as possible we have written the first two chapters to cover installation and use in an introductory way Important Please read at least the first two chapters of the SkyGuide User s Manual before using ATCS for more than the installation testing described at the end of this document Introduction to the Astrometric Telescope Control System for SkyWalker1li on Custom Telescope Mounts Installation of SkyWalkerti This section describes how to install and test the components of Astrometric Instruments SkyWalkerl Telescope Control System when purchased with Pittman serv
10. omotors and separate servo drivers This system includes a SkyWalkerl Telescope and Accessory Controller two servo drivers two Pittman servomotors with integral gearboxes and necessary cabling Optionally Astrometric Instruments can provide suitable power supplies such as our APS 150 or APS 230 power supplies for SkyWalkerl and the servo drivers When purchased as a whole this system is called SkyWalkerl1i Note do not attempt this installation unless you are adept at handling electronic components Misconnections can damage the servomotors servomotor encoders servo drivers SkyWalker1 or power supplies For each telescope axis follow these installation steps Mount the servomotors and servo drivers Important Notes The RA and Dec servomotors are separately labeled They should not be swapped since Astrometric Instruments has pre tuned the motor driver pairs The electrical connections to the servo driver should be made firmly Any looseness in the connection can lead to erratic behavior It is advised that the wires be individually and gently pulled to check for firm connection Do not power up any of the electronics until all of the connections are complete otherwise loose wires can short to each other or other conductive objects and cause damage to the system Mount the servomotor to a metal surface that provides some amount of heat sinking The motor s continuous torque rating is limited by how much heat ca
11. rvo encoder to servo driver if not already done so as follows Black wire to ENC Red wire to ENC Yellow wire to PHASE A Blue wire to PHASE B Connect SkyWalker motor cable to servo driver The motor cable wire coming from SkyWalker1 is a 6 wire flat modular cable The end of this simply needs to be plugged into the 6 pin modular connector on the ASM The HardLimit switch What is the HardLimit switch It is a customer supplied and customer installed normally closed switch that should be mounted so that it opens in the event of telescope movement past hard limits The HardLimit connections are inputs that must be pulled to signal ground in order for SkyWalker s drive signals to be active Normally closed series connected mechanical limit switches placed on the telescope must be used to pull the HardLimit inputs to signal ground for ordinary operation These HardLimit switches must be placed to protect against telescope movement beyond safety or mechanical limits When a HardLimit switch is opened or the connection from the HardLimit input to signal ground is broken for any reason the Step and Dir outputs are disabled Introduction to the Astrometric Telescope Control System for SkyWalker1li on Custom Telescope Mounts To use a HardLimit switch with SkyWalkerli simply connect it so that in normal safe telescope positions it shorts the two pins of the 2pin 0 100 header on the ASM One pin
12. s not provide GoTo capability nor interface to Planetarium software nor a plethora of other features provided by SkyGuide requiring a PC running Windows 95 98 ME In System mode the control system operates attached to a PC running our SkyGuide Telescope Control System Software for Windows95 98 ME Functionality increases dramatically with features such as automatic GoTo coordinate Planet or over 16000 deep sky objects optical encoder support allowing for manual movement joystick control and control from one of the many commercial or shareware planetarium programs available today running on the same or remote PC System Mode requires a Pentium 120 or better PC one communications port RS232 and the Microsoft Windows95 98 ME operating system Introduction to the Astrometric Telescope Control System for SkyWalker1li on Custom Telescope Mounts Upgrades Functional upgrades are continuously made to ATCS New features user s suggestions requests and bug fixes require this These functional upgrades primarily involve SkyGuide however from time to time it may be necessary to upgrade the firmware i e embedded software in SkyWalker As a customer of Astrometric Instruments upgrades to SkyGuide are available free of charge from our web site at www astrometric com Upgrades to SkyWaker s firmware are available at cost Visit our website to see if an upgrade is available Documentation upgrades are available as PDF files t
13. sing a separate servo driver power supply i e not an APS unit then you will need to make the following connections to the power supply Connect the red fused positive power leads both RA and Dec to the positive terminal on the power supply Connect the black negative power leads both RA and Dec to the negative terminal on the power supply Note the separate power supplies provided by Astrometric Instruments should be mounted under cover to protect from human exposure and to protect from moisture e g heavy dew For these separate power supplies Astrometric Instruments does not provide a line cord to 10 Introduction to the Astrometric Telescope Control System for SkyWalker1li on Custom Telescope Mounts connect the power supply to an AC source For separate power supplies all connections to AC power are the responsibility of the customer Connect the servomotor to the servo driver if not already done so as follows Note when setting up the SkyGuide telescope control system software it will be necessary to set the number of motor steps per sky revolution This value is derived by multiplying the total gear reduction between motor shaft and the sky by the number of steps per motor shaft revolution The number of steps per motor shaft revolution is as follows for the 5 9 1 and 19 7 1 gearboxes number of steps per motor shaft revolution 5 9 1 gearbox 11794 8717 19 7 1 gearbox 39316 2393 Connect the se
14. ut connector step Dir output Figure 2 connection The function of each ASM component is SkyWalker connection provides direct 6 wire modular connection to SkyWalkerl Connections include 5v Gnd Step Dir Gearlndex and HardLimit GearIndex input this accepts a 4 wire modular cable from Astrometric Instrument s standard GearIndex sensor board HardLimit connector a 2 pin 0 100 connection for HardLimit switches Supplied with a shorting jumper pre installed It is recommended that the shorting jumper be replaced with connection to a suitable HardLimit switch The section below entitled HardLimit Switch and the SkyWalker Owner s Manual provide more detail e HardLimit override button and LED In the event of a HardLimit condition the HardLimit red LED will light An override button is provided to clear the HardLimit condition as long as the button is depressed Introduction to the Astrometric Telescope Control System for SkyWalker1li on Custom Telescope Mounts Step Dir and Reset outputs connect from the ASM to the servo driver and relay the appropriate signals from SkyWalkerl and the ASM s on board current limit circuitry to the servo driver HighLoad LED Current sensing wires from servo driver Important do not change the adjustment of the Gain Damp and especially the Limit potentiometers on the servo driver They are properly adjusted prior to shipment Wire up t
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