RC24 Focuser - Revision history

WikiSysop: /* New Electronics */

2014-09-06T05:40:00Z

New Electronics

← Older revision		Revision as of 05:40, 6 September 2014
Line 87:		Line 87:
	<center> Phidgets 1065 DC motor controller.</center>		<center> Phidgets 1065 DC motor controller.</center>

	The controller receives logic power from the USB bus and motor power from a separate motor power supply (up to 28 VDC). It accepts standard TTL A and B encoder phases, and it supplies 5 V encoder interface power. The connectors also ~~accepet~~ analog input from two temperature sensors and digital input from two lines.		The controller receives logic power from the USB bus and motor power from a separate motor power supply (up to 28 VDC). It accepts standard TTL A and B encoder phases, and it supplies 5 V encoder interface power. The connectors also accept analog input from two temperature sensors and digital input from two lines.
	[http://www.phidgets.com Phidgets] open source libraries may be used to develop programs in C and Python on Linux, Windows, and Mac OS platforms.		[http://www.phidgets.com Phidgets] open source libraries may be used to develop programs in C and Python on Linux, Windows, and Mac OS platforms.

WikiSysop at 05:09, 6 September 2014

2014-09-06T05:09:40Z

← Older revision		Revision as of 05:09, 6 September 2014
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	The SPDT spring loaded switch on the enclosure connects ground to the two digital inputs. The inputs may be read in software to enable an observer at the telescope to make focus adjustments. The original TCC hand control paddle is no longer used because the RC24 telescope is operated by a remote observer.		The SPDT spring loaded switch on the enclosure connects ground to the two digital inputs. The inputs may be read in software to enable an observer at the telescope to make focus adjustments. The original TCC hand control paddle is no longer used because the RC24 telescope is ordinarily operated by a remote observer.

	==Software==		==Software==

WikiSysop: /* Software */

2014-09-06T05:07:54Z

Software

← Older revision		Revision as of 05:07, 6 September 2014
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	*focus_reset resets the encoder reference count		*focus_reset resets the encoder reference count
	*focus_show_all displays the encoder count, mirror position, and PSF FWHM		*focus_show_all displays the encoder count, mirror position, and PSF FWHM


	*temperature_read inquires, displays, and saves the temperature readings		*temperature_read inquires, displays, and saves the temperature readings

WikiSysop: /* Software */

2014-09-06T05:07:41Z

Software

← Older revision		Revision as of 05:07, 6 September 2014
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	</center>		</center>

	The available commands for focus are		The available commands for focus and temperature are

	*focus_change_microns moves the secondary a commanded distance in microns		*focus_change_microns moves the secondary a commanded distance in microns
Line 116:		Line 116:
	*focus_reset resets the encoder reference count		*focus_reset resets the encoder reference count
	*focus_show_all displays the encoder count, mirror position, and PSF FWHM		*focus_show_all displays the encoder count, mirror position, and PSF FWHM

	~~as well as~~

	*temperature_read inquires, displays, and saves the temperature readings		*temperature_read inquires, displays, and saves the temperature readings

WikiSysop: /* New Electronics */

2014-09-06T05:04:48Z

New Electronics

← Older revision		Revision as of 05:04, 6 September 2014
Line 87:		Line 87:
	<center> Phidgets 1065 DC motor controller.</center>		<center> Phidgets 1065 DC motor controller.</center>

	The controller receives logic power from the USB bus and motor power from a separate motor power supply (up to 28 VDC). It accepts standard TTL A and B encoder phases, and it supplies 5 V encoder interface power. The connectors also ~~provide~~ analog input from two temperature sensors and digital input from two lines.		The controller receives logic power from the USB bus and motor power from a separate motor power supply (up to 28 VDC). It accepts standard TTL A and B encoder phases, and it supplies 5 V encoder interface power. The connectors also accepet analog input from two temperature sensors and digital input from two lines.
	[http://www.phidgets.com Phidgets] ~~provides~~ open source libraries to develop programs in C and Python on Linux, Windows, and Mac OS platforms.		[http://www.phidgets.com Phidgets] open source libraries may be used to develop programs in C and Python on Linux, Windows, and Mac OS platforms.


Line 100:		Line 100:

	The SPDT spring loaded switch on the enclosure connects ground to the two digital inputs. The inputs may be read in software to enable an observer at the telescope to make focus adjustments. The original TCC hand control paddle is no longer used because the RC24 telescope is operated by a remote observer.		The SPDT spring loaded switch on the enclosure connects ground to the two digital inputs. The inputs may be read in software to enable an observer at the telescope to make focus adjustments. The original TCC hand control paddle is no longer used because the RC24 telescope is operated by a remote observer.


	==Software==		==Software==

WikiSysop: /* Focus Mechanical System */

2014-09-06T05:02:33Z

Focus Mechanical System

← Older revision		Revision as of 05:02, 6 September 2014
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	The upper end of the rotating actuator shaft is 4 mm in diameter. It is coupled with the 4 mm drive shaft of the Pittman motor by a flexible coupling that allows for minor shaft misalignment with no backlash. Thus one rotation of the motor shaft advances the secondary mirror 1/20 of an inch. A counterclockwise sense looking toward the primary from the motor ~~effective~~ backs the actuator screw out of the translator shaft and forces the secondary toward the primary. Similarly, a clockwise rotation pulls the secondary away from the primary toward the motor by 1/20 inch or 1270 microns per turn.		The upper end of the rotating actuator shaft is 4 mm in diameter. It is coupled with the 4 mm drive shaft of the Pittman motor by a flexible coupling that allows for minor shaft misalignment with no backlash. Thus one rotation of the motor shaft advances the secondary mirror 1/20 of an inch. A counterclockwise sense looking toward the primary from the motor backs the actuator screw out of the translator shaft and forces the secondary toward the primary. Similarly, a clockwise rotation pulls the secondary away from the primary toward the motor by 1/20 inch or 1270 microns per turn.

	Motion toward the primary is stopped by a brass tab attached with a 10-32 screw to the back of one of the two support rods. The tab meets the inside of the coupling housing and blocks forward movement before the mirror actuator unscrews from the drive rod. In the opposite direction, the motion of the secondary away from the primary is stopped when a rotating arm on the motor shaft hits the edge of the cap screw holding the brass tab.		Motion toward the primary is stopped by a brass tab attached with a 10-32 screw to the back of one of the two support rods. The tab meets the inside of the coupling housing and blocks forward movement before the mirror actuator unscrews from the drive rod. In the opposite direction, the motion of the secondary away from the primary is stopped when a rotating arm on the motor shaft hits the edge of the cap screw holding the brass tab.

	The rotation of the drive screw is very smooth and requires little torque, except for a few sticky places. In the course of the refitting in 2014 we lightly lubricated the shaft and screw with comparator oil when the motor was removed to assess whether there was significant binding. The photo above shows the motor in its flange temporarily held out of the way with one of the flange mounting screws. Access to the coupling set screw is through the slots for the spider vanes.		The rotation of the drive screw is very smooth and requires little torque, except for a few sticky places. In the course of the refitting in 2014 we lightly lubricated the shaft and screw with comparator oil when the motor was removed to assess whether there was significant binding. The photo above shows the motor in its flange temporarily held out of the way with one of the flange mounting screws. Access to the coupling set screw is through the slots for the spider vanes.



	== New Electronics ==		== New Electronics ==

WikiSysop: /* Software */

2014-09-06T05:00:44Z

Software

← Older revision		Revision as of 05:00, 6 September 2014
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	<center>		<center>
	[http://www.astro.louisville.edu/software \| Shared Skies Software]		[http://www.astro.louisville.edu/software Shared Skies Software]
	</center>		</center>

WikiSysop at 04:59, 6 September 2014

2014-09-06T04:59:59Z

← Older revision		Revision as of 04:59, 6 September 2014
Line 102:		Line 102:

	The SPDT spring loaded switch on the enclosure connects ground to the two digital inputs. The inputs may be read in software to enable an observer at the telescope to make focus adjustments. The original TCC hand control paddle is no longer used because the RC24 telescope is operated by a remote observer.		The SPDT spring loaded switch on the enclosure connects ground to the two digital inputs. The inputs may be read in software to enable an observer at the telescope to make focus adjustments. The original TCC hand control paddle is no longer used because the RC24 telescope is operated by a remote observer.


			==Software==

			Focusers on the RC24 and CDK20 telescopes are controlled by Pyfocus, a suite of Python programs that provide for command line and scripted operation, and monitoring focus setting and temperature. The open source and MIT licensed code is available from our servers here

			<center>
			[http://www.astro.louisville.edu/software \| Shared Skies Software]
			</center>

			The available commands for focus are

			*focus_change_microns moves the secondary a commanded distance in microns
			*focus_change_pixels changes the PSF FWHM a commanded number of pixels in the CCD image
			*focus_get reads the last encoder count
			*focus_reset resets the encoder reference count
			*focus_show_all displays the encoder count, mirror position, and PSF FWHM

			as well as

			*temperature_read inquires, displays, and saves the temperature readings

WikiSysop: /* New Electronics */

2014-09-06T04:51:50Z

New Electronics

← Older revision		Revision as of 04:51, 6 September 2014
Line 99:		Line 99:
	[[File:RC24_focuser_new_electronics.jpg\|center\|800px]]		[[File:RC24_focuser_new_electronics.jpg\|center\|800px]]
	<center>The RC24 focuser electronics package with a test motor before installation on the telescope.</center>		<center>The RC24 focuser electronics package with a test motor before installation on the telescope.</center>


			The SPDT spring loaded switch on the enclosure connects ground to the two digital inputs. The inputs may be read in software to enable an observer at the telescope to make focus adjustments. The original TCC hand control paddle is no longer used because the RC24 telescope is operated by a remote observer.

WikiSysop at 04:48, 6 September 2014

2014-09-06T04:48:52Z

← Older revision		Revision as of 04:48, 6 September 2014
Line 98:		Line 98:

	[[File:RC24_focuser_new_electronics.jpg\|center\|800px]]		[[File:RC24_focuser_new_electronics.jpg\|center\|800px]]
	<center>The RC24 focuser electronics package before installation on the telescope~~. The motor is a similar one to the focuser motor but with a gearhead~~.</center>		<center>The RC24 focuser electronics package with a test motor before installation on the telescope.</center>