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Detailed Configuration Settings
| This page explains all of the configuration settings for the DrzTrack program. 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
antenna. 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. 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. |
| 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. The Switches presently only have 1 possible
option other than the default shown here. Switch 3 can be set to
be used to enable High Resolution mode for 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.
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. |
| The Cancel button abandons any changes you may have made in the configuration window, and returns you to the main setup window. |
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.