AWR IDS SYSTEM OVERVIEW
BRIEFLY... The AWR IDS SYSTEM provides state of the art performance for tracking, control, position readout and PC interfacing. It is programmable by the user to fit onto new or existing scopes. The system uses an Intelligent Drive Box to control all motor movements with readouts, control and calibration from the handset. It is fully portable requiring only a 12V DC power supply. It does not need a computer, even to perform GOTOs. With a computer, the major Planetarium programmes, such as 'THE SKY' or 'SKYMAP PRO' can issue GOTO commands or can track the telescope. It is suitable for ALL TELESCOPES WITH SLOW MOTIONS operating up to 5 degrees per second depending on configuration. Target system accuracy is 20 arc seconds. Upgrades to the firmware in the Intelligent Handset and Drive box are supplied to system purchasers at nominal cost. Full details of the Intelligent Drive System are in our handbook to buy or to download.
INTELLIGENT HANDSET FEATURES
Intelligent handset hardware features:
Intelligent Handset Issue 1.6 software features:
Future planned firmware release features will include:
If there are any other features you wish to see included then please contact us. All the software has been developed by ourselves to get the performance and features we thought were necessary.
PRICING (UK & Europe)
REQUIREMENTS OF TELESCOPE MOUNT
RA and DEC slow motion controls are required with reduction ratios 144:1 and upwards. There should be enough space for the motors, a minimum of 60mm x 60mm x 75mm for the smaller motor. The larger motors are up to 125mm long. There is also a leadout wire near the back of the motor. Many standard telescope mounts have been fitted including EQ5, EQ6, ALTER D6 etc. Systems for these can be supplied from stock.
Small mounts have small motors fitted and gearing about 3:1 using either timing belts / pulleys or gears to get the motor motion onto the slow motion axes.
If the telescope requires too much torque we can supply additional gears to drive it with the Microstepping system. There has not been any telescope we have failed to drive. We can also supply brackets, or undertake complete equatorial head refurbishment by fitting worm wheel sets etc.
Overall system pointing accuracy specification is about 20 arcseconds depending on reduction ratios. This means that various calibration adjustments will be provided to take out miscellaneous mechanical errors that your mount and telescope may posess. See article with further details of possible mechanical errors.BASIC DRIVE BOX [MICROSTEP]
This unit can be used stand alone with the SIMPLE HANDSET or with the INTELLIGENT HANDSET. It provides two independent frequency generators with microstepping translation to drive RA and DEC axes according to programmed drive rates. The power stage is configured to drive the normal or high power stepper motors. Internal memory stores programmed rates when the power is removed. Drive waveforms have a base resolution of 1 microsecond. Fast slew up to 5 degrees per second achieved depending on telescope geometry and torque required. Virtual encoders provide a pulse every 64 microsteps (equivalent to about 20 arcseconds with a 360:1 worm reduction). Slew is achieved by constant acceleration (programmable) from starting frequency. Sidereal rate would be approximately 50 microsteps per second and maximum slew is about 60,000 microsteps per second.
The BASIC MICROSTEP DRIVE BOX needs either a simple handset or the Intelligent Handset to operate. It can also accept an autoguider lead. With an adapter, the IH connector on the drive box can connect to a PC serial port allowing full remote operation.
ADVANCED DRIVE BOX [MICROSTEP]
For the advanced telescope facility, AWR offer an expanded drive box offering extra input output facilities in addition to the standard MICROSTEP or FREQUENCY GENERATOR drive box. These include:
ADVANCED END ELECTRICAL INTERFACE DIAGRAMS
FURTHER INFORMATION on AUTOGUIDERS
DRIVE BOX [FREQUENCY GENERATOR]
This drive box is exactly the same as the MICROSTEP product but does not have the microstepping. It is designed to drive smaller motors which already possess a gearbox. It has the same Intelligent Handset connection, serial protocols and programmability as the MICROSTEP box. The limitation is that of high speed stepping, standard steppers cannot go that fast without a higher voltage drive and this drive box contains a high voltage board to provide a useful speed increase to get most small motors up to about 60 times sidereal rate.
This product can be used as a very powerful upgrade for any stpper motor system already installed. The original motors must be 4 polar uniphase driven motors. It does NOT however provide very fast slews and a much better option is to replace the motors.
The standard DRIVE BOX is supplied with a simple handset and has a connector to plug in the Intelligent Handset. With an adapter, the IH connector on the drive box can connect to a PC serial port.
A simple handset on a 3m cable with UP DOWN LEFT RIGHT buttons and speed adjust for GUIDE, CENTRE and SLEW movements. Once the MICROSTEP drive box has been programmed, this simple handset can be used at the telescope on its own or with the Intelligent Handset.MOTORS
We have stadardised on the Sanyo Denki precision stepper motor range and various types can be offered to give torques in the range 30Ncm up to 210Ncm and with an additional gearbox can provide 400Ncm up to high slew speeds. The correct combination will be offered by discussion with our sales person.
A typical motor has been characterised with a torque loading
of 9.5Ncm as follows. A mirror was attached to the motor shaft in addition
to the torque load. A laser beam directed at the mirror produced
a spot measured at a distance of 8.8 metres. There are several loading effect
(a) When at the pole (full step position) there is a static shift of +10 microsteps.
(b)During a 64 microstep sequence (one pole to the next one) the torque available varies and superimposes a wobble of +/-7 microsteps.
(c)There is an additional variation from pole to pole of +/-3 microsteps.
This all adds up to a backlash due to the torque loading and a ripple (periodic error). With our system driving a 360 tooth worm these errors correspond to a positional variation no more than 6 arcsec including a ripple of +/-1 arcsec. The other motors gave similar performance with the same percentage rated torque load.
DRAWINGS OF MOTORS
STEP LOADERS - A PC software package to converse directly with the Microstep Drive Box. This provides uploading and downloading of all the programmable values. A spreadsheet allows calculation of the correct programme values. Alternatively the text file of values can be altered to change the Drive Box rates.
For advanced users - an alternative strategy is to use a terminal programme and converse with the Microstep Drive Box in low level protocol. A PC software programme can be written to converse directly with the serial port and so use the DRIVE BOX directly. Commands are available to push the direction buttons at the four speeds - Guide, Centre, Move, Slew speeds. There is data flow to tell when the telescope is tracking or moving, when backlash operation is in progress. In addition there is access to all the registers containing the drive rates for all the speed settings.
PLANETARIUM PROGRAMMES can supply GOTO information when the Intelligent Handset connects to the PC, or they can track the position of the telescope. It becomes a simple 'point and click' to goto the next object. The whole data base of objects in the Planetarium programme is then available to you.
The AWR PROTOCOL mode allows access to information flow from the drive box as well as the higher level commands into the handset. Powerful command set allows remote control of the whole telescope, including operation of the User relays contained in the Advanced Drive Box and remote star calibration.POWER SUPPLIES
Later software versions will be supplied on programmed EPROM chips that will need to be exchanged within the Intelligent Handset or the Microstep Drive Box. When an upgrade is available, the information will be released to all system purchasers stating what will be offered by the improvement. There may be charges depending on what is involved.A DEMO UNIT
We have a small commercial Newtonian mount with worm sets and this drive system. This will be taken around to exhibitions. Please watch our webpage for details of forthcoming exhibitions we will be attending.
© 1997-2005 AWR Technology