AG Optical-Thermal Control System Manual

AG Optical-Thermal Control System Manual
AG Optical-Thermal Control System Manual
Introduction
The AG Optical Systems Thermal Control System (TCS) consists of:
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TCS Control Box
AGO Thermal Manager software application (Windows compatible)
Primary mirror cooling fans
Primary mirror heater
Secondary mirror heater
Primary mirror temperature sensor
Secondary mirror temperature sensor
Ambient temperature sensor
Cabling
The system is designed to maintain the temperature of the primary and secondary mirrors
to above ambient air temperature by automatically turning on and off the heating and cooling
elements of the TCS according to a set of parameters set by the user. Given the wide variability
of factors affecting the thermal behavior of the telescope system, AG Optical System designed
the TCS to be a simple but effective system that the user can easily monitor and adjust to achieve
the best possible performance for their specific telescope system.
The AG Optical Thermal Control System consists of hardware that uses temperature
sensors that reads the ambient temperature as well as the surfaces of the primary and secondary
mirror to heat and cool the mirrors that is controlled by an application on your computer. Both
mirrors can be heated to warm their surfaces and the primary mirror can be cooled using the fans.
Multiple sensor reads are made every ten seconds, and a weighted smoothing function that
incorporates a moving average together with a median noise filter is used for a stable display and
readout.
Minimum System Requirements: XP, Win7 or later.
Hardware requirements. Be sure to power the Thermal Control Box using a high
quality, regulated 12vdc power supply with at least 1.25 amps capacity. The USB connector and
12 VDC power port are located on the back plate side of the TCS Control Box.
1.25 amp
Regulated
12VDC
Power
Supply
12VDC
USB
Computer
Connect the TCS Control box to a 1.25 or higher, regulated 12vdc power supply.
Connect the USB port to your computer or hub that is connected to your computer.
Wiring Diagram
Below is the wiring diagram describing how the various thermal control system elements
are connected. A simple numbering and color scheme (1 through 6) is used to ensure each
element is properly connected to the TCS Control Box…….Yellow connects to Yellow, Blue to
Blue, etc. Some of the connection points are located on the telescope back plate.
1.5 amp
Regulated
12VDC
Power
Supply
Top
12VDC
USB
Computer
“1”
“1”
5 amp
12VDC
Power
Supply
“2”
Primary
Temp
Sensor
(Red)
AD
“2”
AD3
“3”
“3”
Secondary
Temp
Sensor
(Yellow)
R2
“4”
“4”
Secondary
Heater
(Green)
R1
“5”
“5”
Primary
Heater
(White)
R0
“6”
“6”
Primary
Cooling
Fans
To 12VDC
connector
on
telescope
back plate
Seventeen inch and larger iDK models have four cooling fans installed on the carbon
fiber mirror shroud. These fans greatly reduce internal air currents by scrubbing the boundary
layer of warm air on the face of the primary mirror. The 12vDC center pin positive power
connector and speed control knob for the shroud fans is located on the back plate and is
identified by the letters “Sh”.
The other power connectors on the back plate are for the primary cooling fans and TCS
temperature control elements (if applicable).
Hint: It is suggested that you use two separate power supplies for the TCS Control Box. A
quality, 12VDC regulated power supply capable of supplying at least 1.25 amps should be used
for the power source for the TCS Control Box (underlined in the diagram above). A separate
12VDC power supply capable of supplying at least 2.5 amps should be used to power the cooling
fans and heaters. Damage to the control board may occur if a non-regulated or non-switched
power supply is used.
Software Installation. Before installing the application, be sure to plug the power
cable to supply power and the USB cable to the AGO-Thermal Control System Board and
the computer. Wait a few seconds and then run Setup. On first startup, you will see a warning
that the TCS hardware is not connected, and asks if you wish to select the COM port from the
Configuration Menu or exit. If the board is powered and the USB cable is connected, click on
[email protected] and you will see the TCS Main window. From there, click on "Settings" from the topmenu, and then click on "Serial Port Configuration" and select the correct COM port. Otherwise,
click no to connect the cables and restart TCS. If the correct port is selected from the Serial Port
Configuration window, click on [email protected] text will change to AConnected" if the proper Com
Port was selected. After the application finds the port, the main window should start up and be
operating in [email protected] mode. The status bar should also correctly display the assigned port to which
it is connected. If, by some chance, you select an incorrect com port it will not connect and will
display a warning that the TCS board could not be found. Once a correct serial port is connected,
it will use that same serial port when you restart the application without further need to reselect
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the Com Port. If, for some reason that port changes (which could occur if you plug other USB
devices that use a serial port before you connect the TCS hardware and a different serial port is
assigned, simply go to the Serial Port Configuration page and select the correct serial port again.
Hint: When you connect a USB cable to the TCS hardware and your computer (or hub, if that is
connected to your computer), a com port is assigned to the TCS hardware. If you are not sure
what com port the TCS hardware should use, remove the USB cable, then left mouse-click on the
Start button (on Win7; using Win8 change to Classic Mode), then right-click on [email protected] and
click on [email protected] and then click on ADevice [email protected] If you see APorts (COM & LPT)@, click
on [email protected] to see the ports installed and then plug in the USB cable. The new com port should
appear. If APorts (COM & LPT)@ is not listed, plug in the USB cable and it will appear. Click on
APorts (COM & LPT)@ and the Com port created will be shown. Select that com port from the
Select com Port Configuration page in TCS.
Start the application. Start the application by clicking on the AGO-Thermal Control
System icon:
The application has three modes:
Off: turns off all relays and sensors and stops temperature readings;
Auto: starts an automatic routine to read sensors and monitor and controls the
temperature of the mirrors by turning on heaters or the primary mirror fan; and
Manual: allows the fans and heaters to be controlled manually.
By default, TCS starts up in [email protected] mode. Each mode is described below.
Off. All sensors and relays are disabled and OFF. The manual controls are not enabled.
Auto. In AUTO mode, the manual controls are not enabled. The ambient temperatures
are monitored, and if needed, the Primary is heated or cooled with the fans. The secondary can
only be heated. While in AUTO mode, there are three variables that can be modified to fine tune
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the time the fans or heaters are on, or when they come on or off based on temperature. On the
Configuration window, you will find these three settings. The display will show the status of each
relay as well as the status bar. The changes are effective immediately when entered and are saved
upon exiting the application. If you wish to have the application start up in Auto mode each time
TCS is started with no user interaction, simply click the [email protected] checkbox from the
Configuration page. The next time TCS is started, it will then start in Auto mode, using the
Threshold and Duty Cycle and all other settings saved from the previous session. Note that in
Auto Mode, it must cycle through one cycle before any heat or fans will begin. For example, if
you have the ON or OFF cycle to 60 seconds, the heater or fans will not turn on for the first 60
seconds. Note the Status bar will indicate AAuto Control [email protected] when Auto is selected. There also
will be short delay while TCS initializes, which is also indicated on the Status menu. A flashing
"heartbeat" star is displayed each time the temperatures sensors are read.
Manual. In Manual Mode, the Manual controls are enabled as are the temperature
sensors, and clicking on the control turns on the relay, and clicking it again turns it off. The
display will show the status of each relay. Fans and Primary Heaters may not be on at the same
time; however, the primary fans and secondary heater may both be on at the same time in case the
primary has not cooled down as fast as the secondary mirror.
Hint! If you manually turn on the heaters, be aware they may warm the mirror excessively
if you forget to turn them off.
Settings. Clicking on Settings controls the Auto-Timer, Configuration, Enable/Disable
Logging, Serial Port Configuration, MiniTCS, and Temperature settings.
Auto-timer Settings. If you want the Auto Control features to be enabled and
disabled at a set time, from the Settings Menu, select Auto-timer. There you simply enter
the Start Time and End Time and click AAuto-Timer [email protected] While waiting for the Start
Time to begin, you may use the three controls as you normally would do (Off, Auto, and
Manual). A red warning on the Main Menu will be displayed advising an Auto-timer job
is pending. At the start time, no matter what mode is selected, the mode will change to
Auto. You can use this feature to turn on the heaters in the morning and then off later in
the day automatically, for example, after an imaging run at a designated time and without
any user interaction to prevent dew. While running, whatever configuration settings you
have selected will be used during the run. You may change these settings as well during
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the before or during an auto-timer automated run.
Configuration Settings. If you select Configuration you will find three settings that
make adjustments to tune the auto settings for accuracy.
Threshold Adjustments. Threshold settings simply set the temperature
that the heaters and fans use to determine when the heaters or fans are engaged or
disengaged. Default is ambient. In other words, if the settings are at their default
setting of 0, the heaters will turn on to warm the mirror until they are brought up
to the ambient air temperature, or turn the fans on to cool the mirror down to
ambient. The same works for the secondary, except it only can heat the secondary
to ambient. Then, the heaters or fans turn off until there is a need to heat or cool
the mirror(s) again. There are three settings. One, in blue, is to set the temperature
the fans will turn off. There are two in red that determine the temperature the
heaters will heat the mirror before turning off. You may not set the heater
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threshold setting lower than .2 degrees above the fan setting for the Primary
Heater setting to keep them from both being engaged at the same time. You may
set the Secondary heater setting up to 10 degrees higher than ambient, no matter
what the Primary is set for as it is independent of the Primary settings.
On the main window, when Auto is selected, the Target Temperatures as
adjusted by the Threshold settings are displayed to make it easier to both
understand and set the desired temperature ranges of the fans and heaters. The
ambient temperature is always displayed in green. The primary mirror
temperatures are displayed in blue if the temperature of the mirror is below the
target temperature and in green if it equals or is between the target temperatures for
the heater and fans as set forth in by the threshold settings on the configuration
page. The secondary is displayed in blue if it is below the ambient plus threshold
temperature settings as set forth in by the threshold settings on the configuration
page, and green if it exceeds the target temperature. That way, you can quickly see
how well the target temperatures are being maintained.
If you leave the threshold settings at 0.00 for all three settings, if the mirror
is warmer than ambient the fans will come on and cool the mirror until it reaches
the ambient air temperature. If the mirrors are cooler than the ambient
temperature, then the heater will come on and heat the mirror until ambient is
reached. When the primary reaches ambient, if weather conditions are stable, there
is a possibility that the heater and fans will cycle back and forth. If the temperature
is falling or rising usually this is not an issue. To keep the primary heater and fan
from cycling back and forth where the air temperature is fairly stable, it is
recommended that a setting of at least .4 or so for the primary heater and .1 for the
fans be set as the threshold settings. This creates a Adead [email protected] of .3 which should
be enough to keep the devices from cycling, and keep the mirror above ambient to
keep dew from forming. If not, increase it accordingly - simply increase the fan
values by .1 or so and the positive values for the primary heater until the cycling
stops. Setting the primary fans within .2 degrees of the heater is not allowed, and
the heater temperature will be adjusted to the minimum difference. You may
increase this difference, but not reduce it beyond .2 degrees. The goal is to set the
values so that the temperature of the mirror is what you want it to be and not cycle
between heating and cooling the primary mirror. Normally, temperatures are
falling, and so the primary mirror follows the actual ambient air temperatures.
However, if the ambient air temperature is falling and the later rising, then the
threshold setting for the fans should be set high enough so there is a difference
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between the two that cycling does not occur.
If you notice constant cycling between the primary heater and fan, simply
change the settings so there is a larger difference between the Primary Fan and
Primary Heater settings until the cycling stops. You may also disable the fans and
both heaters separately by clicking the Disable appropriate checkbox on the
Configuration Settings page for each.
Duty Cycle Settings. In order to avoid tube currents, the heaters cycle ON
and OFF so they do not become overly warm. The Duty Cycle settings allow you to
control how long each ON and OFF duty cycle will be. The default is 30 seconds.
The number is in seconds, so if you change the Off cycle to 25, for example, and
the ON cycle to 30, the heaters will stay off for 25 seconds, and then cycle On for
30 seconds and will repeat until the mirrors reach the ambient settings (plus or
minus the Threshold Settings as stated above). Settings less then 10 seconds are
not recommended.
Ambient Sensor Adjustment. Although the sensors are quite accurate,
different sensors can read slightly differently. By adding or subtracting an amount
set forth in this setting, you can adjust up or down the readout of the each
temperature setting. If you are satisfied each are accurate at the default setting of
0.00, then make no adjustment. If you wish to adjust these values, you may add or
subtract a value as needed.
Recommended Settings. The settings depend on the ambient temperature.
A setting of 30 seconds is recommended, depending on the ambient air
temperatures nothing more. As the mirror begins to get close to ambient, reduce
the cycle settings to a value that will maintain the setting you desire for the mirrors.
Note that fans do not cycle and stay on until ambient is reached. If you notice that
the mirror temperatures are too cold or too hot, reduce the duty cycle setting until
you see a fairly stable setting. The ambient temperature plays the largest role in a
proper setting rapidly decreasing temperatures, for instance, will require fans, but
the secondary will follow along since it is only passively cooled. On the other
hand, once the secondary reaches ambient (or the target temperature), it should
maintain the correct temperature closely, but will rise and fall as heat is applied,
and the heater turned on, and off. If the target temperature is more than a degree or
so above the target temperature, reduce the duty cycle so less heat is applied.
Some trial and error is needed to determine the exact settings, but generally, the
settings as set forth above seems to work well in fairly moderate conditions (25FAG Optical Systems | [email protected] | 256-541-0218 | www.agoptical.com
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70F). Optimally, the best settings are those that turn on the heaters for no more
than absolutely necessary to prevent dew.
Fan and Heater Controls, Clicking off the checkbox will disable the
Primary, Secondary, or Fans during Auto-Mode. This function has no effect in
Manual Mode.
Simulation Mode. If the checkbox is selected, TCS will simulate an
Auto mode control session using randomly generated temperatures for the
Ambient, Primary, and Secondary mirrors temperature readings. It connects to a
simulated Com 10 port (no actual port is connected). The TCS board does not
have to be powered, or connected to the USB cable to your computer. To disable
Simulation Mode, uncheck the box. A window will pop up advising you to select a
Com Port to continue from the Serial Port Configuration page. If you do not wish
to do so, simply click OK, but you will not be able to use Manual or Auto Mode
features until you either re-select a Com Port from the Serial Port Configuration
window or re-select Simulation Mode from the Configuration Window. If you exit
TCS while in Simulation Mode, and Auto-Start is selected, and the TCS hardware
is not connected or powered, TCS will again start up in Simulation mode using
whatever settings were last selected from the Configuration window. To connect
to the actual Com Port, uncheck the Simulation Mode checkbox, and re-select the
actual Com Port used by your computer to connect to the TCS Hardware.
Sound. If checked, when the relays are turned off and on, a relay-click can
be heard, and when the fans are on, a fan sound can be heard. The feature is
enabled by default. Un-checking the checkbox disables all sounds in both Manual
and Auto modes.
Enable Logging. Under the Configuration menu, you will find an optional
AEnable [email protected] feature. Clicking on this will either create a new log text file if one
does not exist or append a log to an existing file every 15 seconds. The log will report
the date and time and which relays are engaged and what the temperatures were that as
read by the sensors (as adjusted by the Configuration Settings above). The file is by
default located at AC:\Users\Public\AGO\Log.text. To disable, simply click on
ADisable [email protected] from the same menu if logging was enabled. A green label will be
displayed on the Main Menu when logging is engaged. If Logging was enabled when
TCS was last exited, the log will restart automatically next time TCS is launched.
AutoStart.
If Autostart is checked when the TCS application is closed, on
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the next start up of TCS, it will start up in AUTO mode, with all the settings that were
in effect when TCS last closed. If Simulation mode was selected when TCS was last
closed, it will start up in Simulation Mode and in AUTO mode, with the settings that
were in effect when TCS last closed.
MiniTCS. If you only want to monitor the temperatures of
the ambient, primary and secondary mirror while in Auto Mode, and
don’t want the see the entire TCS main window display on the
Desktop, from the Settings menu, click on “MiniTCS. Note that
TCS must be running in Auto mode for the MiniTCS to be
displayed. Clicking the left-mouse button anywhere inside the
MiniTCS window will make the Main AGO-TCS window visible
again and the MiniTCS window will be hidden.
Temperature Chart. Click on [email protected], ATemperature [email protected] and a chart as
displayed above will open showing in real time the actual temperature readings.
Temperature readings are taken every five seconds, no matter how often the chart updates.
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You may set the graph interval in 10 second, 1 minute, and 15 minute intervals. This will
display readouts for the last 5 minutes, 32 minutes, and 8 hours, respectively. The
temperatures can be followed to verify that the mirror temperatures are always above
ambient to avoid dew. You may also directly change the Primary duty cycle settings
without having to open the Configuration page. Note that the chart is only available in
Auto mode.
Closing TCS and saving settings. Simply click on the Top Menu AFile/[email protected] or click on
the [email protected] icon in the upper right window. All settings in the configuration window will be saved
upon closing, and the mode setting will be placed in the [email protected] position before the program exits.
Summary. In practice, what has been observed is that in moderate climates, the primary
mirror is almost always warmer than the ambient air temperature as the air temperature falls much
more rapidly than the temperature of the mirror, even with the fans on, until very early in the
morning. With the fans on, however, it will stay very close-and should be within at least .5 (half a
degree) of the target temperature the majority of the time. If you set the threshold value of the
fans, for example, at 1 degree over ambient, it should cool the mirror to this temperature, and keep
it there, all night long +- .5F. The primary heater is rarely needed to be engaged.
On the other hand, the secondary will not only fall to ambient very quickly, observations
show it will actually fall below ambient if not heated. Since dew only forms when the dew-point
equals or is below the ambient temperature (if the dew-point is below freezing, the frost will
form), it is important to keep the mirror warmer than the ambient temperature to prevent dew or
frost. If the threshold setting is set for 1 degree over ambient, it will fall to that temperature, and
remain there, during your session, preventing any chance of dew, slightly going a bit below the
target and a bit above, usually +- .2 degrees.
A recommended threshold setting for the fans at around .3 to 1 degree above ambient, the
primary heater at .2 and the secondary a .2 to or above, with a duty cycle of 30 to prevent dew
works well. However, with that being said, you should make yourself aware of the dew point and
ambient humidity levels and adjust your threshold settings accordingly. Settings for the secondary
that work well in moderate climates would be .3 above ambient with a duty cycle of 15-20. Use
higher settings for high humidity environments or where very cold temperatures are observed to
prevent dew from forming. If you notice that the mirror temperatures can't quite keep up with the
falling ambient temperatures, increase the On cycle and reduce the OFF cycle slightly. The
settings will change based on the meteorological conditions, but the optimal settings are always
the minimum settings for the ON and Off cycles that will do the job and nothing more. As the
imaging session progresses, simply take note of the temperatures and make any adjustments
needed to add more or less heat desired. Since the weather conditions can vary from extremely
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cold to hot, it is impossible to have a setting that works in all weather, so be aware of the
conditions, and set the threshold settings accordingly.
Troubleshooting
1.
I can't connect to the serial port. This is usually caused by (1) not having the
12vdc power supply connected, or not using the proper voltage or (2) not having the USB cable
plugged into the computer or hub that is attached to the computer, or (3) selecting the wrong com
port from the serial port configuration window. Once you connect, TCS should automatically find
and connect after the first connection. On occasion, if you install other hardware that uses the
same port when TCS is not connected, the correct port assignment could change as well for TCS.
If that occurs, simply try to connect using the correct port from the Serial Port Configuration
window.
2.
TCS is not maintaining the set temperatures. If the mirror stays below the ambient
plus threshold setting, increase the "On" time. If it is too hot, simply decrease it. You should also
increase the "Off" time to avoid tube currents and while it is not required, closely follow On time
settings. If the temperature of the primary is not being cooled sufficiently, check the small black
knob on the back plate to be sure it is in the highest fan speed position. It has been found that the
Secondary mirror heater will take longer to warm the mirror than the Primary if they are both set
on the same settings. You may want to increase the ON cycle for the Secondary heater if it is not
warming the mirror sufficiently.
AG Optical Thermal Control System
Copyright 2014-2015 by AG Optical Systems, LLC
All Rights Reserved
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