Instruction manual

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IN/OUT. On the left is a box into which you can type your intended relative motion, e.g., 50 steps. Now
you can click IN or OUT and the focuser will move as directed. This is very useful in fine focusing.
Absolute/Relative (A/R). To the right of the position window is a button labeled A/R (the R is red). This
button is a toggle. That is, if the absolute position is being displayed, e.g. a black 3000, and the button is
pressed, a +/- red relative value will be shown, e.g. a + red “0” zero. Now if you move the focuser using
the in/out buttons you will see the motion relative to the setting present when you toggled to the Relative
mode. You return to absolute by toggling A/R again. This is very useful for keeping track of the net
movement in and out during focusing!
Focuser Movement. You can command motions of the focuser in one of two ways:
• Position Box Enter the desired position into the position box and hit enter and the focuser will move
to the desired location.
• In/Out Controls. You can enter the number of steps to change in the IN/OUT box, then click IN or
OUT and the focuser will move accordingly.
Refresh. When you click this button, RFCP queries the controller to get the current position and
temperature as well as other configuration data. The current position is displayed in the window to the
right. This position is updated upon a refresh, and at the conclusion of any move.
Configuration Screen
This screen is used to read or set the configuration items of the RoboFocus control program and controller.
Communications. The first time you use the RoboFocus, you will need to select the CONFIGuration
menu item. Then select Adjust CommSettings. This will show a screen with various communication
parameters. One of these is the COM port. You will choose the serial COM port you intend to use. You
will usually be using COM port numbered one through four. The rest of the settings are 9600 baud, 8 bit, 1
stop bit. Note that you can connect/disconnect the COM port without turning the program off. The COM
port will close when the program is closed.
You can now make or break your COM connection from the RFCP by clicking on the Open/Close COM
button on the main window. When you OPEN the COM port, you automatically issue commands to refresh
the RFCP data (version number, current position, and remote power module settings.)
At this point, if you have established communication with the RoboFocus, you will see the current position
displayed. The current position updates itself only when you first turn on or when you do a computer
directed focus move, or when you click the Refresh box to query the RoboFocus and renew the reading.
The RFCP does not poll the RoboFocus controller on a regular basis.
Backlash. Backlash is the “mechanical lag” in the mechanical movement of the focuser itself. That is,
depending on the loading of the focuser and whether you are moving in or out, after moving in one
direction, you may have to move for a substantial distance before actual reverse focus movement begins.
To compensate for this, the RoboFocus can operate the commanded distance plus extra steps for
compensation, then reverses the extra steps so that all moves, no matter what the direction, are finished
with motion in the same direction. Factory default is compensation set for inbound, 20 steps. This
configuration control allows you to turn compensation to a value of 0-64,000 for IN bound (all motions
FINISH with movement in the INbound direction) or OUTbound.
The backlash compensation need not be set precisely—all that is needed is to take up the focuser system
slack in the direction of concern. Experience shows that with a stepsize of four, approximately 10-20 steps
of the RoboFocus are usually enough to accomplish this on a R&P focuser, while the LX200 may require
100 or more steps to accomplish the backlash correction.