AstroHub Tips and Techniques (updated
12/09/04)
What follows is a collection of miscellaneous Tips and Techniques for
installing and using your AstroHub. These are here because they were
posted after the User's Manual was published or just didn't fit into any section
of the manual. Please send
us any tips or techniques you find that may be useful to other users.
- Mount Power Connections
Please note that only the hot side of the mount power is switched
through the AstroHub if the power switching feature is used. The ground side
is connected to AstroHub ground. This means if the mount power
connector is arranged so the tip (the center pin) is negative and the ring
(the outer connection) is the voltage connection and care is not taken in
wiring power connectors to plug into and out of the AstroHub mount power
connectors a short circuit will be created. This will not normally be
a problem for the large majority of mounts available today. We
understand that the Vixen mount in one such mount with reversed power
wiring. If you need help in how to wire you mount if it isn't standard
please contact Tech Support or post you question to the AstroHub group. (top)
- Stepper Plug-in Power
Sequencing
There are conditions where power and USB sequencing is required.
If a focuser or filter wheel is physically connected to Port1 or Port2 on
the AstroHub and 12V Main Power is connected to the AstroHub the stepper
motor windings may be simultaneously energized drawing a large amount of
current. The current level will be within the rating of the motor
driver circuit on the Stepper Plug-in but may overheat if left in this state
for a long period of time. This *may* damage the Stepper
Plug-in. The recommended procedure is to always insert the USB cable
before applying main power to the AstroHub. (top)
- RoboFocus Settings Transfer
When using a Stepper Plug-in as a RoboFocus controller, all of the settings
normally stored in the RoboFocus control box such as current position, step
size, duty cycle, etc. are now stored in the plug-in microprocessor EEPROM
(non-volatile memory). To easily transfer the settings from the
control box to the plug-in follow this simple procedure:
Connect the RoboFocus and the control box for it as usual, apply power, and
start the RoboFocus Control Program (RFCP). Assure the settings the
RFCP has are what you want and the focuser position is where you want it for
the position value the RFCP shows. Close the RFCP and disconnect the control
box from the RoboFocus. Connect the AstroHub to the RoboFocus and
connect 12V input power and the USB connection to the PC. Start the
RFCP and set it for the COM port the Stepper Plug-in is using (Use the Show
Devices utility to quickly determine the COM port). Do not move the
RoboFocus from its current position. Simply position the cursor in each of
the settings boxes of the RFCP and press Enter. This will transfer the
setting shown to the Stepper Plug-ins memory where it will be saved.
Be sure to do this for the current position value. From this point, everything
should operate exactly as if the RoboFocus control box were attached
independent of what software is driving the AstroHub. (top)
- Plug-in Assembly
Plug-ins are packaged with a nylon spacer and stainless steel screw for
securing the plug-in into the base unit. These parts are basically an
"overkill" since the rigid connectors the plug-in mates with
provide significant retention. The extra hardware is not really needed
unless you expect your AstroHub to see a lot of vibration or
shocks from transporting it, etc.
If you do decide to install the extra hardware, you will find that the screw
provided is just a tad short and requires the plug-in to be tilted a bit to
start the screw. A longer, modified screw is now available
to alleviate the tilting problem. Subsequent
manufacturing runs of the product will use the longer screw. If your
plug-in(s) did not come with the longer screw and you would like them, please email us and
we'll send as many as you need at no charge. (top)
- Optec Focuser Added Feature
The control box supplied with the Optec focuser runs the focuser to the full
in stop and then back to the last known position whenever the focuser is
powered up. If the last position was close to the full in position,
the focuser continues to run up against the stops for almost the full 7000
counts. While a Crayford focuser can tolerate this type of operation occasionally,
repeated use this way could cause grooves in the metal wall and possible
sloppiness and slippage in the focuser operation. The newly available
Optec firmware for the Stepper Plug-in will default to this operation unless
the new feature is used. This feature overrides the default operation
described above by not moving the focuser on start-up and assuming the
focuser has not been moved and is still at the last position which is stored
in persistent memory on the plug-in. The AHSetup program has been
updated to include a way to set this new feature or return to the
default. The setting is saved in persistent memory so only needs to be
set once. A button on the set up screen is also available to "center
and calibrate" the focuser in the event is is moved while the power is
off. This button causes the focuser to move to the full in stop and then
move to the center point and store the 3500 center position in persistent
memory (EEPROM) thereby fully calibrating the focuser position.
Note that the control box that comes with the Optec focuser is only required
if you wish to run the built-in, automatic temperature compensation In this
case you would connect the control box to an available serial port on the
AstroHub. If the temperature probe is attached to the focuser, the
Stepper-Plug-in will make temperature measurements and return them to the
requesting software if that is all you require. In this case the
control box is not needed. (top)
- Possible False Error Report
A few of the early base units and plug-ins have a small, non-functional bug
in the bootloader code used to oversee the re-flashing of any firmware in
the base unit or plug-ins. The effect of this is that the flash
utility will report an error in verifying the new version number of the
firmware at the end of the flash operation. The error is invalid in that
the re-flash operation fully succeeded and the version number has been
updated. You should use the AHSetup program to verify that the
plug-in, in fact, works and that the version number is at the version you
were flashing to. It will most likely be fine.
The firmware error is in the part of the firmware that oversees the flash
operation and therefore cannot not be re-flashed itself. If you wish
to have your unit updated to eliminate this problem, please contact us and
arrange to return your unit and plug-ins to each be reprogrammed.
There will be no charge for this service but shipping is not covered.
This problem will only occur during flashing operations and not affect the
actual operation of your AstroHub at all. Even then, the error is incorrectly
reported and the flash operation will be shown to be
successful. (top)
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