Transcript
System Team Members
Panel & Electrical System
PLC Controlled Dome
Dome Control
CdS Cell Sensor Design
PLC
CdS Cell Sensor Schematic
Allen Bradley PLC-5/25 processor Analog Input (1771-IL) Interface
Conversion: Circuit converts analog voltage to Transistor Transistor Logic (TTL) level voltage Resistance: CdS cell resistance is approximately 500 ohms when the laser is on and 1 Mega-ohm when the laser is off.
• 12-bit 0-5 Volt, 0-20 mA TTL input.
Discrete Output (1771-OAD) Interface • 120/12 Volt relay output.
Ladder-logic Implementation • Up to 50,176 I/O implementations • Average scan per I/O rack, single chassis: 0.5 ms. • Allen Bradley RS-View Software for ladder design.
PLC-5/25 Nate Erni, Evan Howard, Ben Jeppsen
Weather / Telescope
Controller Panel
Control Schematic Diagram
Panel
Control
Hoffman AA30H24DLP 24”x36”x12” Motorized System Hand/Off/Auto and E-Stop
• Rotational (dome) induction motor control • Open/Close shutter induction motor control • Physical limit switches define rotational angle
• Provides isolated PLC or manual user control. • Shut off power to loads
Soft Motor Starter
Motor Protection
Matt Pine, Brok Thayn, Scott Farnsworth
Weather PLC Program / GUI Design
• NEC (National Electric Code) Regulations. • Overcurrent (fused) protection. • Motor Disconnects • Directional interlocking
• Limits voltage vs time for soft ramp-up
Power Control Relay • Double-pole double-throw polarity switching • 120V/24V, 10A, 1/3 HP Rated
Rocky Mountain Space Grant Observatory
Program Description
Abstract Aggie Observatory’s goal is to make astronomical instruments available to people around the world through the internet. This gives authorized students and members all around the nation access to hardware via the internet. This network of telescopes will allow students to use expensive equipment without their own setup cost. This will also provide students located even where sky observations are poor to whet their interest in space by a click of their mouse. All telescopes are in fixed locations, and "using them" means sitting down at an internet-connected computer, logging onto the instrument, and starting to see and record images. This avoids hours of set-up and tear-down work at the beginning and end of the observing session, and it's possible to do other things (like your homework) while taking long exposure images.
•The weather condition values will then be put into the metadata file.
Metadata files and GUI • Periodically read in and store metadata into a table format with a date and time stamp. • The current weather values are displayed on the GUI.
Output Signal: AC sine wave, or frequency, 1 cycle per revolution, 0.75 m/s per Hz.
Hardware Setup
CCD Camera Meade Digital Sky Imager Pro II Monochrome
Operating Temperature: -50 to 50°C
5V
AutoStarII Suite •Software allows user to access a database of celestial objects, and remotely guide a telescope viewing: • 45,000 stars • 13,000 clusters • 8,350 comets •This level of precision requires in-depth calibration, and matching of telescope, computer, and interface sub systems.
Sine Wave to Pulse Conversion
100k R4
R1 10k
R3
3
1k
LM358 R5 1 2.4k
1V 10k
Q1 2N3904
Circuit used to convert the AC signal of the anemometer to a pulse (digital) wave. Needed to input the anemometer directly into the PLC.
8
10u
+
2
Vin
-
C1
4
12V
0
0
HMP45C Temperature Sensor Supply Voltage: 7 to 35 VDC Power Consumption: <4mA @ 12 V Output Signal: 0.001 to 1 VDC Operating Temperature: -40 to 60°C Measurement Range: -40 to 60°C
TE525 Tipping Bucket Rain Gage Supply Voltage: 12 VDC Output Signal: momentary VDC pulse when switch closes due to tip Rainfall per tip: 0.01 inches Operating Temperature: 0 to 50°C Sensors made by Campbell Scientific
Supplied Voltage: 5 VDC Output Signal: TTL Level Voltages Array Length: 24 CdS Cells CdS Cell Resolution: Each CdS Cell represents 2º of resolution Implementation: Sensor array will be mounted to the base of the telescope
We would like to thank our many sponsors for making this project possible. Our sponsors include ATK Launch Systems and Allan Bradley for the donation of the PLC and operating software. Rocky Mountain NASA Space Grant, with Josh Williams as the chief engineer of the consortium, Chad Henager for the electrical installation, and USU for the financial and design support throughout the project.
Measurement Range: 0 to 112 mph; gust survival of 134 mph. R2
CdS Cell Sensor Implementation
Special Thanks To Sponsors
Weather Routine •Open/Close Shutter Routines. •Check weather conditions. •Compare weather conditions to determine if weather is good or if bad. •Output signal that opens or closes the shutter. •Continuous weather check every 5 ms.
03101 R.M. Young Wind Sentry Anemometer
CdS Cell Array Schematic
CdS Cell Sensor Array
April 28, 2008
•Convert the voltage readings of the sensors to the actual weather conditions.
Weather Sensors
Routine Check Module
DSI Imaging •CCD Camera provides 16-bit quality photos, with pixel size near 8.4 micro-meters square. Storage formats include Jpeg, TIF, FITS, and others. •Software is highly specialized, having parameters to be adjusted for vibration tolerance, ambient light, minimum quality, and number of composite photos.
Images
Telescope
•Pictures taken through haze on 3/18/2008 of the Moon and Saturn
Meade 14” LX200R
Future Work This design was engineered to be a part of the Space Grant Internet Telescope Network (SGITN), lead by North Dakota Consortium. SGITN requirements specify that a dome operator be present during any operation of the dome. Requirements for the operator include checking the weather forecast daily and report to the SGITN indicating if weather conditions allow the dome to be used. The operator will also be present during any operation to ensure that the dome is functioning properly. If an error occurs the operator will manually shut the dome down, repair, and restore control to the user. A web-accessible interface will allow users within the consortium to access and control the dome from any location. A power failure protection system, using a uninterruptible power supply (UPS) will provide power to the shutter motor to automatically close in the event of a power failure to protect the telescope equipment. Limit switches will be installed to prevent over-rotation of the dome staying within predefined limits of the telescope. Visit http://www.rmspacegrant.googlepages.com
Group Members Systems Leads • Scott Farnsworth Weather • Matt Pine, Brok Thayn, Scott Farnsworth, Monica Berrett Controls / Dome • Ben Jeppsen, Nathan Erni, Evan Howard, Scott Farnsworth Telescope • Brok Thayn, Scott Farnsworth, Matt Pine, Monica Berrett
