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|This page explains all of the detailed settings for the DrzTrack program. Here are links to the various topics|
|When first getting started, all
that is required is to select the correct encoder type
for Azimuth and for Elevation, and set the appropriate
ranges, but once you have the initial setup and testing
done you may need to fine tune the controller to your
requirements. The configuration window and explanation
for each item follow. Since the settings for azimuth and
elevation are the same, I will only explain for azimuth. Note that
hovering the mouse pointer over any of the fields will cause a 'tool
tip' to pop up, giving more explanation about what that field is for.
|Calibration range should be set to the points that you wish to use
when calibrating the controller. This allows the
controller to calculate the number of degrees for each change in
position from the encoder, and set the exact current position of the
Usually it is best to use standard positions like 0-360 or 0-90*, but your situation may require you to use something else. Note that the F1EHN and Nova programs do not handle rotation values greater than 360 degrees, so even if you can rotate your antenna in a greater range, 360 degrees is all you will be able to use with these programs.
As of version 2.11 and firmware version 2.4, setting up your azimuth system with a south stop is supported. Check the 'South Stop' box above. The program will ask you if you wish to use default settings. Normally you should click 'Yes', and then modify where needed. The default settings for south stop set the calibrate and tracking Min/Max to 180 degrees, since the south stop is at 180 degrees.
*For absolute inclinometers, and shaft encoders with 1:1 gearing, it is necessary to use a 360 degree range as the calibrate end points. See the absolute encoder paragraphs on the Control Program page.
|The tracking range is used to set the limits that you wish the antenna to move to during actual tracking. These values can be either greater or less than the calibration min and max points. For example, you might have your elevation calibration point set at -10 degrees, but during tracking want it to stop at zero degrees.|
|Move precision and Move timeout work together to set the
controller's motion detector and emergency shutdown feature. In normal
operation the controller receives motion commands from the controlling
program. It then operates the relay
to start a position motor. The antenna starts moving and
the controller monitors and reports the current position
back to the controlling program. When the antennas reach
the desired position a stop command is sent and the
controller disengages the motor relay. However if the
antenna rotation mechanism is jammed, or a stop is
reached, the antenna may not move when commanded. This is
where the motion detector comes into play.
The Move Timeout value specifies a number of seconds, from 0 to 60, with a default value of 5 seconds. As long as the antenna is moving, the controller board checks every 5 seconds (or whatever period you have Move Timeout set for) to see if the antenna has moved during that period. It compares the position at the beginning of the period to the current position. If the values are the same, or not reasonably different, the controller goes into it's emergency shutdown procedure. It stops all motion motors and disables itself so it will not act on any further motion commands from the controlling program.
However it is not sufficient to merely check to see that the antenna has not moved at all. Even a jammed antenna may rock back and forth slightly as the motors attempt to move it. If the antenna were to hit something with a little 'give' like a tree branch, it may rock back and forth quite a bit. This would provide enough motion to 'fool' the motion detector. For this reason we have Move Precision. Move precision is a value, in tenths of a degree, of how much motion can be reasonably expected from the antenna in the period specified by Move Timeout. The default value is 10 tenths (1 degree). The minimum value is 1 tenth and the maximum value is 100 (10 degrees).
So, with default settings, if the antenna does not move at least 1 degree every 5 seconds, the emergency shutdown will operate. Your antennas may move significantly faster or slower than this, or you may wish to check more often or more seldom than every 5 seconds. Set the values of Move Timeout and Move Precision to suit your installation.
Once the emergency shutdown has operated, the controller will accept no more commands until it has been reset. This can be done with the reset button on the DrzTrack main window, or by power cycling the controller board.
|Most antenna rotation mechanisms cannot instantly reverse direction without the possibility of damage to the mechanism or to the antenna itself. The Restart Time setting is used to prevent whiplash. It is the time, in seconds, that the antennas must be stopped before starting motion again. The value can range from 0 to 15 seconds.|
|There are several modes and methods of speed control
available, depending on your setup. There is a Slow speed
method and a Jog method. Look at the next paragraph for
Jog information. Slow speed is controlled by the variable
called 'Slow Degrees'. This has two modes depending upon
your control program.
Slow speed is controlled by pins 7 and 8 of the male DB9 connector (X1). Pin 7 will go high when the elevation should turn slowly, and pin 8 is used for azimuth. You need to connect these pins to your own external circuitry to reduce the speed of your motors.
F1EHN: If you are using the F1EHN Tracker, the value is not degrees, but seconds. Setting a value other than zero activates this function. Possible values are 0 to 255 seconds. Each time the motor is started the slow output pin will be active (high). After the number of seconds specified in Slow Degrees have elapsed the voltage at pin 7 or 8 will go low, indicating that you can increase motor speed. There are no speed control outputs for stopping the motors but most systems will 'coast', making stop speed control unnecessary.
Other Programs: For all other programs the value you put into the Slow Degrees field is the number of degrees, from 0 to 255 from either side of the target position that the slow outputs will be activated. This works for both starting and stopping the antenna, so if you use the default value of 10 degrees, the slow outputs will be active whenever the antenna is within 10 degrees of the target.
|The second method of speed control is called jogging. This
works by starting and stopping the motors periodically when the antenna
is near the target. The 'Slow Degrees' value controls the range in
which jogging is active, and the settings are the same as described
above for "Other Programs". Jogging is enabled for each motor by
checking the 'Jog Control' check box. Then you can specify the
length of time that each motor will be on, and the length of time that
it is off.
For firmware versions prior to 5/03, the default values are 1/2 second on, and 1 second off, but they can be set to any value from 0 to 255, in tenth seconds. So the on and off times are between 0 and 25.5 seconds. If you have an all electronic way to switch your motors on and off (our HexFet board for instance), or really good relays, you could switch the motors on and off each tenth of a second, which should result in a smooth half speed.
We have discovered that for some mounts it is necessary to be able to control the jog speed to shorter values than .1 seconds. So, starting with firmware version 5.03, the jog time increment is now .01 seconds, allowing setting jog time between 0 and 2.55 seconds (jog field will read - to 255).
|Many programs do not monitor the position of the
antenna, but rather only send the desired position to
the controller. So it is up to the controller to
determine when the antenna has reached the desired
position, and stop motion. The Stop Precision is a
measurement of how close to the specified position the antenna must be, before it is stopped. The value
is in tenths of a degree and ranges from -128 to +127 (-.11.8 to
+12.7 degrees). The Start Precision specifies how far beyond the
current antenna position the target can move before the antenna will be
started moving again. The value is in tenths of a degree and
ranges from 0 to 255 (0 to 25.5 degrees).
Note that when negative values of Stop Precision are specified, the antenna will actually move past the target before it stops. So if the value is -20, the antenna would move two degrees past the moon before it stops. In that case, the value of Start Precision cannot be less than or equal to 20 (+2 degrees). The DrzTrack program will not allow you to enter values for Stop and Start precision that result in an overlap.
These setting are used for all tracking programs except for F1EHN, which handles stopping the antenna internally, sending a stop command to the controller when needed.
|Clicking the Az or El defaults button at any time will load a set of default values into the screen fields of the configuration dialog. These defaults are slightly different depending upon what encoder you have selected. This provides an easy way to get a reasonable starting point for changes you may wish to make.|
|Once you have entered the desired values, use the Send button to save those values. They are sent to the controller board and stored in it's nonvolatile memory. The next time you enter the configuration window you will see the new values that you set.|
|These buttons allow you to save the current configuration, including current antenna positions and counts, to your PC, and to restore them when desired. Click for Details.|
|Clicking the Switch and LED configuration button brings up the
following Dialog box. Currently the switches are fixed function,
and there are no options. For firmware versions prior to 5.01,
switch 3 has an option to be unused or to specify the resolution for the
absolute encoders. Switch 4 is unusable and must remain in the off (up) position at all
times. In the future more switch options may be enabled.
The default setting for the Single LED on the controller board is as a transmit indicator that can be controlled from DrzTrack or the F1EHN program. If you do not want to use it for this, you may disable that usage and select one or more of the other possible usages.
You may use it to show when the antennas are being jogged, to blink when the Zero Index pulse on incremental encoders is passed, or to light up when the movement timer fails and stops the antennas. Click the Send button to send these values to the controller.
If you have not used the Send to Controller button, the Cancel button abandons any changes you may have made in the configuration window, and returns you to the main setup window.
controls the CT-2 board to provide tracking of Moon and Sun.
There are two ways that other programs may interact with the CT-2
controller board. One is via direct serial communication from
the tracking program to the controller. The F1EHN, MoonSked,
and EME2008 programs use only the serial mode. The TrakSM
can use serial mode when they it is configured for the NovaComm or EasyComm
modes. TrakSM may also be used in the DDE mode; Nova and SatScape can only be used in DDE mode.
DDE stands for "Dynamic Data Exchange", and is a method for multiple programs running on the same computer to communicate with each other. A tracking program that uses DDE is said to be a DDE server and it sends tracking information to another program via DDE. The DrzTrack program is a DDE client and can receive this tracking information and then relay it to the CT-2 controller board via the serial port interface. When DrzTrack is functioning in this manner, the Tracking section of it's screen will show the name of the body or satellite being tracked, and the current position of that body as determined by the DDE messages from the tracking program. In this mode, the actual tracking program (Nova, SatScape or TrakSM) may be minimized on your computer screen and the DrzTrack screen will show both the current satellite position and current antenna position.
When DDE tracking is started. tracking will be stopped, requiring you to click the 'Start Tracking' button to start moving the antenna. This is a safety feature so the antenna does not start moving until you can see it happening on the DrzTrack screen
If you are using a tracking program that directly communicates with the CT-2 controller via the serial port, you must set up DrzTrack to use that program. Then the program can be run right from DrzTrack. When you end the tracking program you will automatically return to the DrzTrack program where you can test or reset calibration if necessary. This saves a lot of switching back and forth between programs. When running one of the DDE trackers it is necessary to run it from DrzTrack so that both are operational at once.
The Run button in title section of the tracking box in the main DrzTrack shows the name of the tracking program being used. Initially this will always be DrzTrack itself, you must specify any other tracking programs you wish to use and where they are located on your computer, and what the interface method is. If no external tracking program is specified then the Run button will not be shown.
Third party tracking programs are set up in theSetup menu, 'Program Options' selection, in the Programs tab. Here you will see a list of all programs that you have already set up.
Click the 'New Program' button to add a new program.
To edit an existing program name or settings, left-click the program name in the list.
Once one or more programs have been added to the list, you can select the one that you want to currently use with the drop down box at the lower right. This is the program that will be assigned to the 'Run' button in the main dialog.
is the first tab of the Program Options dialog. Here you
select the Com Port and baud rate that you will use to communicate
with the controller. The Serial Ports drop down box will only
show ports that are found on your computer. If the port you
want is not shown then it is not configured or not working.
The default baud rate for the CT-2 is 9600 baud. It can be changed with on board switch settings, but there is little value to higher rates. The system works very well at the 9600 baud rate.
There are 5 check boxes to enable or disable program features. They are described below.
The right side of the window is for configuring the display and usage of the signal or polarity field on the main DrzTrack dialog. When set to "No Show" the field will not be shown. The other options are "Show Signal" and "Show Polarity". If either option is selected the field will appear on the main dialog with the appropriate label.
This feature allows display of a zero to +5 volt input value connected to pad 5 on the controller board (use pad6 for ground). If Signal is selected then the field will show zero to five volts. This could be connected to the AGC output of a receiver, for instance, to show signal strength. It could also be used for any other analog voltage. Care must be used to ensure the voltage does not exceed +5 volts. Using a 7 volt Zener diode in parallel with the voltage input (between pad5 and pad6) is recommended. (If you use a 5 volt Zener the diode will start to conduct as the voltage approaches 5 volts, distorting the readings.)
If "Show Polarity" is selected then the lower portion of the window will be populated with instructions for setting up the polarity display. You must have a 0 to 5 VDC output from your antenna polarity encoder (potentiometer). Set the polarity to horizontal, enter zero degrees in the start degree field and then click the 'Set' button. The input voltage will be read and displayed in the 'Reading' field. Then rotate the polarity to 90 degrees, or whatever your end point will be, and enter that position into the End degree field. Then click the set button and get the reading for that position. Next click 'Apply' or 'Ok' to save the settings. Now the polarity in degrees will be shown on the main dialog. To the left is how your completed setup might appear.
Fast Boot. When checked, the display of boot messages in the
main dialog, and on the LCD display (if present) is greatly speeded
5. Allow Scaled Absolute Az. See Absolute Encoder Calibration in the DrzTrack page for details.
For information on the Programs tab of the Program Options dialog, see Tracking with other Programs, on this page.
The left hand side of the dialog is where you can set up what
I call 'Positional Offsets'. This is for when there is some
anomaly in the rotation of your antenna, for either Azimuth or
Elevation. Consider what happens if the gear or pulley that drives
your Azimuth encoder is not mounted at the exact center of rotation of
the antenna mount. This will cause slight variations in the
encoder output value as the antenna is turned. Normally these
variations are very small and can be ignored, but when operating on a
high microwave band with a large dish antenna, even a few tenths of a
degree error can cause loss of signal. A similar problem exists
when the antenna mount is not perfectly aligned with the surface of the
earth. This means that the rotating mast will tilted a slight
amount in some direction. When the antenna rotates the tilt will
cause the beam to be low in some directions and high in others.
Another example is that the potentiometer or other encoder you are using exhibits some non-linear characteristics. For example, when the antenna is horizontal, the reading is correct, but as you elevate the antenna the reading becomes more and more in error.
Positional Offsets are designed to adjust for such anomalies. It is complicated to think about how this works, and often two people discussing it find that they both are saying something different but meaning the same thing. So it is impossible for me to design a system that will be the way every person thinks. Instead I have picked a scheme and provided several ways to enter, or measure and enter the offsets. I hope this explanation will make sense to most of you.
Positional Offsets use data tables that are entered by the operator and saved on the computer (not in the controller). The saved data contains values for various points in the rotation or elevation of the antenna. Each point contains the number of degrees for the point and the offset at that point. The DrzTrack program will interpolate between these points to determine the correct offset to apply at any given antenna position. Any fixed band offsets will also be added at the same time, so the total offset will be Band Offset + Position Offset.
For Azimuth the first point must be at zero degrees and the last position must be 360 degrees. For Elevation the start and end are at zero and 90 degrees. All points in the table are at even numbered degrees (fractional degree values will be rounded). A point may be entered for each degree in the range 0-360 or 0-90, however in practice no more that 4 or 5 points should be needed because the program interpolates between points and usually the offset change will be linear, or fairly linear over a quarter turn.
Once the table is created and saved (by pressing Apply or OK), it must be enabled before it will be used. Check the box 'Enable this List' to start using the offset table.
Ok, now that you understand the tables, here is how to enter them. There are three methods:
1) Probably the simplest way is to click the little + button just below each table. This will bring up a window where you can enter a position and offset. It is not necessary to enter the positions in any special order, they will be added to the table in order by degree. This method can only be used if you already know what your antenna offset is at the various positions.
2) You can rotate your antenna to each position and then measure the offset. When you use this method you then enter the measured offset in the 'Offset' field below the table and then click the 'Set' button. This adds the point and current position to the table.
3) Measuring the offset may be difficult. You can try to bore sight it against a known object such as the Sun or Moon, but it is easier to use method 3, where the offset is automatically calculated for you. To the right of the two tables is a check box labeled 'Auto-Calculate Offsets'. When that box is checked the difference between the position that the encoder measures and the current position of the antenna will be shown. By rotating the antenna so it is pointed at the Sun or Moon, either by observation, or preferably by measuring Sun or Moon noise, the actual offset will be displayed in the Offset field and you can simply click the Set button to save it. Of course this method requires that you measure when the Sun or Moon is at various positions in the rotation of the antenna and so might take days to accomplish. However as each new offset value is added to the table the aiming will become more accurate, so you can enter one or two points and then add more points as they are encountered.
When using method 3 very precise positioning of the antenna is required, so I have provided a way to 'Jog' the antenna by small amounts to get it correctly placed. To jog the antenna you click one of the four arrow buttons. Each click turns on the motor for a short time. The time the motor is on is controlled by the 'Position Adjustment Increment' drop down box. The choices are 2, 1, 1/2, and 1/10 of a second. Of course if you have switches to manually control your antenna you can use those instead.
Also note that the LCD display on the encoder will continue to display the exact readout from the encoders, and will not include either positional or band offsets. There is a checkbox in the Comm Port tab of the Program Options dialog that can be used to cause the LCD to display the offset position rather that the encoder position. See the above description of feature checkboxes.
For DrzTrack version 5.10 and later, the absolute encoder programming window has been moved from the setup dialog to the calibrate dialog. So if an absolute encoder is specified for elevation or for azimuth, the corresponding calibrate dialog will show a button labeled "Absolute Encoder Programming". (See below for information on previous DrzTrack versions.)
Clicking the button will bring up this dialog:
When this window is opened, production data is read from the encoder and displayed in the center fields. When you select (click) an encoder shown in the middle list the current values for that encoder will be selected in the set fields below. Then you can change any of them and click the corresponding set button. The new value will be sent to the encoder and then the encoder settings will be re-read and displayed.
You may configure the direction, address, and resolution as you require. The address is the value you are most likely to need to change. As shipped most encoders are set to address 0. The address has to be changed to 1 for use as an azimuth encoder. If you have two encoders set to the same address (0) then you must connect only one of them and change it's address before connecting both.
Low resolution for US Digital absolute encoders gives .1 degree resolution. High resolution may be used if you require .01 degree position accuracy. Note that each encoder may be set for low or high resolution separately. The program detects the setting directly from the encoder and does not require a switch setting (as the previous versions did).
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