PCPOLAR

PCPOLAR is an IBM-PC based menu driven program for the controlling the McDonald Observatory Breger Linear Polarimeter and collection of data from a PMT attached to the polarimeter.

The program was based in part on the old POLAR program that ran on the Data General Nova 4X and Nova 2 systems. With respect to that, many features were kept from the old program, but not all could be accommodated.

If you experience problems and can't find the info you need in this manual, contact the following people:

PROBLEM	PERSONNEL	WORK	HOME	PAGER
Software/General/Instrument Operations	Marian Frueh	x115	426-3716	10
Electronics	Darrin Crook	x167	x652	14
Science Questions	Derek Wills	471-1392

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SETTING UP THE POLARIMETER

HARDWARE

Darrin Crook to write this with input from Marian Frueh.

SOFTWARE

The software on the POLAR PC should already be installed and ready. If not, see the section in this manual on software commands and locations. All of the PCPOLAR software resides in a subdirectory called c:\pcpolar and should have the following items in it.

c:\pcpolar

UPROF <DIR> ........................................ user profiles directory

PCPL.CFG..................................................configuration file

POLAR.EXE...............................................actual executable program

OPOLAR.EXE............................................previous version of PCPOLAR.

BACKUPS <DIR>....................................backups directory (copies of important files)

It is recommended that after setting up the hardware and connecting the computer to the interface box you start the program and run each of the diagnostics (F11). If all diagnostic tests pass, the system should be ready use.

CONFIGURATION FILE: PCPL.CFG

The configuration file is used to set any parameters that might change due to hardware or software requirements. <pulpit pounding mode on> Do not edit this file unless you know what you are doing! <pulpit pounding mode off> ;^) Some edits require hardware changes and some may yield an unusable program.

There are 25 different parameters that can be changed. The order of the parameters is important as the program expects them in a specific order. Those marked with an '*' require a physical hardware change of some type (e.g. moving the UT clock from channel 0 to channel 5 on the clock box). All parameter values are contained inside of the "> <". For a detailed explanation of each, go here.

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STARTING THE SYSTEM

NOTE: Power up all electronics prior to starting the program (it's OK to turn on the computer, just starting the program before everything has been powered up can cause headaches).

After the system has booted, cd into whatever directory you want to put your data (use mkdir directory_name to make a new subdirectory) .

WARNING: Note that you can put only 254 files in a directory (DOS limitation). You might want to use a different subdirectory for each nights observing so you don't have to worry about this.

Then type polar. As the program starts up lots of messages will flash by. Don't worry about them. They are debug messages and are there to give information if the system hangs up for some reason while trying to startup.

If you get an error on starting up the program that says it can't find the configuration file, display the path of the system (type path) and check to see that c:\pcpolar is in it. If not, edit c:\autoexec.bat file and append it to the path statement. If the path is correct and you still have problems, contact Darrin Crook or Marian Frueh for help.

NOTE: Your data will automatically be written to wherever you are sitting on the disk. (If you need to copy your data, make sure you copy both the header and data files to wherever you want. You do not need to worry about embedded path names in the headers.)

THE MAIN MENU & SCREEN:

Most information that one needs to run the system is displayed on the main menu screen. All sub menus are accessed from here.

In the upper left of the main menu you will see the GMT & LST clocks displayed (as read from the Observatory Clocks). It is always a good idea to check to see that these are correct and updating.

GMT : 19:50:40

LST : 12:34:51

At the far right you will see the version of the program that you are running. Ver.: 1.0a

Status Bar: Across the middle you will see a "status bar" with various bits of information. (please excuse the ascii art here)

Below each item listed is the current value of that item.

INT TIME : current integration time in seconds (use the up/down arrow to adjust by 1 second increaments, Ctrl-up/down arrow change in increments of 10s and Alt-up/down arrow to change by 100s.)

BINS/REV: the current number of bins per full turn of the polarizer filter. Default is 42 which given the nature of polarization, bin 'n' and 'n + 21' are the same polarization (where 1<n<=21).

mS/BIN: the number of milliseconds per bin. Default is 2 ms/bin.

mS/REV: the number of milliseconds per full turn of the polarizer filter.

FILENAME: the file name that the current data will be saved as. Filename format is 2 alphanumeric characters followed by 5 numbers. The numbers automatically increment when data is saved.

POLARIZER: the curent state of the polarizer filter motor (stopped/running). Use F8 to start/stop.

FILTER: Current filter position if the filter wheel has been homed, else NOT HOMED! is displayed. Use the F2 - Filter Control sub menu to home, change and name filter positions.

BUF: Current data buffer that will be acted upon by any commands. Valid buffers are A-E (use F4 - Data Buffer Scroll to change). There is also a sky (background) buffer for each data buffer. It is indicated by a small 'b' next to the the buffer value (use the TAB - Toggle Star/Sky to change).

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COLLECTING DATA

To collect data...

Select the buffer that you wish your data to be placed into (use F4 - Data Buffer Scroll & TAB - Toggle Start/Sky).
Choose whether or not to erase any current data that is in the buffer (use DEL - Toggle Data Buffer Flushing).
Select an integration time via the [ALT/CTRL]-up/down arrow keys.
Press F1 (Start Data Collection) (note: if the polarizer motor is not already running, it will be automatically started).

When the data collection starts, the screen will shift to a graphics display mode of the incoming data.
You can switch to the analysis screen by pressing F6 (Analyze Data) and back to the graphics screen by pressing F7 (Graph Data).
You can also use the following keyboard commands:

p - pause integration
r - resume integration
a - abort integration at end of a pass (preserves integrety of data collected so far)
k - kill integration now (integration is ended now and data is flushed)

NOTE: It is not recommended that you type on the keyboard too much while collecting data as it can cause problems in reading the data in (interrupts get delayed because the system was trying to process the keyboard strokes). To switch settings while collecting data it is recommended that you use the switch panel (which does not generate interrupts).

When the data collection is finished, you will be returned to the main menu.

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Detailed Command Information

NOTE: When you are down in a sub menu, most of the time the 'ESC' key will take you back up to the Main Menu.

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F1 - Start Data Collection

This command takes you straight into collecting data (no questions asked). Make sure you have your integration time and data buffer set. If the polarizer motor is not running already, it will automatically be started.

To abort out of the data collection type 'a' to abort at the end of a pass which protects the integrity of the data that has been collected so far or 'k' to kill off now (data is trashed).

User F6 & F7 to switch between the analysis and graphical modes.

Use 'p' to pause an integration and 'r' to resume.

NOTE: It is not recommended that you type on the keyboard too much while collecting data as it can cause problems in reading the data in (interrupts get delayed because the system was trying to process the keyboard strokes). To switch settings while collecting data it is recommended that you use the switch panel (which does not generate interrupts).

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F2 - Filter Control

This sub menu handles all aspects of the filters.

Status: shows whether or not the filter wheel has been homed.

Filter: shows the current filter position (or unknown if the system has not been homed).

Labels: shows the currently defined labels for each filter position. The names are user defined with a default set of (U,B,V,R,I,empty,empty,empty). These names are saved with the user profiles so if you save your user profile and then recall it, your filter set will be reloaded.

I'm not going to go into the details on the different commands available here (F1-F4) since they are all pretty self explanatory.

F1 - Home Filter Wheel

F2 - Move to Specified Filter

F3 - Label Filter Positions

F4 - Return to Main Menu ('ESC' will also do it)

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F3 - User Adjustable Parameters

This menu allows you to adjust various "system" parameters.

F1 - Enable/Disable Dark Mode : This toggles the data analysis to consider the background either dark and unpolarized (e.g. no moon, no bright stars or nebula nearby) or polarized. This only affects the analysis display and the analysis information written into the FITS header. It does not affect the data itself.

F2 - Change Dead Time : This changes the dead time for the Photo Multiplier Tube. The default is 62ns. This does not affect the data stored, only the analysis and what gets written into the FITS header file.

F3 - Change Data Spike Filter : This filter is rarely used. It is used to detect spikes in the data from cosmic rays or from the collection system getting a delay in reading the data from a bin (causes the data to be high in one bin and low in the next as the timing gets back on sync). The values are based on the following formula (note: a value of 0 => filter is disabled [default]):

allowable window = +/- avg data value * 1/n [ 1 <= n <= 10]

F4 - Change Data Collection Timing &/or Motor Speed : I've only got one thing to say about this area, stay away! This is used for those rare times that you need to slow the motor down or get more bins/rev. But, because the number of motor steps must be evenly divisible into 2100 and the bin timing can't be faster than 1ms/bin, it is really tricky to do any of this. I've been told by several people who use the system that you really never need to do this, so again stay away!

F5 - Return to Main Menu ('ESC' will also do it.)

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F4 - Data Buffer Scroll

This command allows you to scroll through all of the data buffers (currently A-E). When collecting data in one buffer, the others are not changed. Be careful about saving your data and not just putting them into a buffer and then not writing them out to disk.

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F5 - Save/Recall User Profile

This sub-menu allows you to save certain characteristics about your environment including the names of your filters, FITS file name, FITS header info (observer,ND filter, detector, telescope) and your default integration time.

All user profiles are stored in c:\pcpolar\uprof\______.pac. You can display those saved via the F3 command. Please take care not to save over other observers' profiles.

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F6 - Analyze Data

This screen can be displayed while data is being collected or just on a static buffer. When collecting data, the screen is only updated once every 10 data passes (still about as fast as you can see).

Star - sky is only displayed when both data buffers are present (e.g. buffer 'A' and 'Ab'). The status of the 'dark mode' is also displayed since it impacts the values displayed here.

See the science section for information on the parameters displayed here.

Press any key to return to the main menu if you are not collecting data.

If you are collecting data you can press 'F7' to go back to the graphical screen or 'a' to abort the data collection (while preserving the collected data) or 'k' to kill off and trash the current data. When the integration is done, you are returned to the Main Menu automatically.

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F7 - Graph Data

This screen can be displayed while data is being collected or just on a static buffer. The graphics wrap around from top to bottom (but not from side to side). The following keys are defined here...

> - Increase X-axis magnification.

< - decrease X-axis magnification.

Page Up - Increase Y-axis magnification

Page Down - Decrease Y-axis magnification

Up arrow - Increase Y-axis roll.

Down arrow - Decrease Y-axis roll.

Press ESC to return to the main menu if you are not collecting data.

If you are collecting data you can press 'F6' to go back to the analysis screen or 'a' to abort the data collection (while preserving the collected data) or 'k' to kill off and trash the current data. When the integration is done, you are returned to the Main Menu automatically.

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F8 - Spin Up/Down Polarizer

This command simply turns on and off the polarizer motor. Note: if you have been collecting data and you turn the motor off, you will have to obtain another CP when you restart it.

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F9 - Continous Count Mode

This mode puts you in a photometry mode where the numbers are displayed on the screen. You are prompted for an integration time (in milliseconds) after which the system starts collecting data. Note: the time base for the part of the program is only the PC clock (not very accurate), so don't publish data with these numbers! However, it is good to help you determine how bright your object actually is as seen by the PMT.

Press 'i' to reset your integration time, 'ESC' to exit and any other key to clear the screen and restart.

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F10 - FITS Menu

This menu allows you to save your data, read back in any data, modify the information that will be written to you header files and enable/disable autosaving of data.

F1 - Modify FITS Header Information : Allows you to change the object name, filename, filtername (to something other than that set by the system automatically), ND filter description, observer name, detector information, telescope information, the storage data type and 3 comment lines.

F2 - Save data : Allows you to modify the header info one last time, prompts for the buffer to be written to disk (note both object and sky buffers will be written, e.g. 'A' and 'Ab'), then writes the data.

WARNING: Note that you can put only 254 files in a directory (DOS limitation). You might want to use a different subdirectory for each night's observing so you don't have to worry about this.

F3 - Read data : Prompts for the buffer to read the data into, then asks for the name (file must be in the local working directory that you started PCPOLAR from).

F4 - Toggle auto save : enables/disables auto saving of data. If enabled, the data will be saved after each integration is finished.

F5 - Display a listing of all the files in the current directory.

F6 - Return to the Main Menu ('ESC' works here as well)

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F11 - Diagnostic Menu

This menu is designed to help the staff check out and/or debug the system.

F1 - Interface Status : checks to see that the computer can detect the interface box.

F2 - UT & LST Clocks : displays the UT & LST clocks as read from the clock box. If an error occurs, the system displays an error message and continues to try to read the clocks. When the clocks start updating, the problem is fixed.

F3 - Polarizer Velocity : does a check of the polarizer wheel to see that the system can see the pipper pulses and that they are occurring in about the right number and timing.

F4 - Filter Wheel : This automatically homes the filter wheel then tries to move it to a given position. This way it checks that the motor moves and that the home and detent switches are working.

F5 - PMT & Counters : see continuous count mode. Shows counts being received by system from PMT.

F6 - Return to Main Menu

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F12 - HELP!

Points you to this website. ;)

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TAB - Toggle Star/Sky

This toggles the incoming data to be placed into either the star (object) or sky (background) part of the buffer (as selected by F4).

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DEL - Toggle Data Buffer Flushing

When enabled a (clear buf) is displayed by the F1 - Start Data Collection and the data buffer that the data will be collected into is flushed (set to 0) before the data collection is started.

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d - Enable/Disable Dark Mode

Toggles the dark mode on/off. Note: this does not affect the data, only the way the analysis is done and thus the values that are written into the FITS header for the analysis.

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s - Enable/Disable Switch Panels

Turns on/off the 2, 16-switch panels. It make the system run a little faster with them disabled, but when collecting data and you want to switch back and forth between the graphics & analysis screens it can be done safely with the switches.

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v - View/Edit data & residuals

Allows you to view the actual data and the fitted data as well as edit the actual data (dangerous unless you know what you are doing, but helpful for removing cosmic ray strikes)

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ALT-h - Flush Current Star or Sky

Allows you to flush out only "half" a buffer while leaving the other half intact (e.g. zero out either the star or sky part of the buffer).

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Switch Panel Operations

The switch panels must be enabled by typing a 's' on the main menu. After that the switches cause action only on a downward change (e.g. flipping a switch up has no action, all action takes place when you flip it down). There is actually a logical reason for doing this, but it is too long to go into it here. If you would like to know why, give me a call in my office (426-4112).

The switches have different meaning depending on whether or not you are currently collecting data.

Non-Data Collection Mode

0	Screen	Return to Main Menu screen from Graph/Analyze Data screens.
1	Advance Filter	Advance filter by one position (filter wheel must be homed)
2	Home Filter	Home filter wheel.
3	T+1	Increase integration time by 1 second.
4	T-1	Decrease integration time by 1 second.
5	T+10	Increase integration time by 10 seconds.
6	T-10	Decrease integration time by 10 seconds.
7	Graph Data	Graph current buffer (data collection mode switches become active) Use switch 0 to exit.
8	Polarizer	Spin up/down polarizer motor.
9	Analyze Data	Analyze current buffer. Use switch 0 to exit.
10	Dark Mode	Toggle Dark mode on/off.
11	Flush Buffer	Toggle data buffer flushing when begining an integration.
12	none	no action
13	Star/sky	Toggle the star (object) / sky (background) buffer.
14	none	no action
15	Start	Start an integration.

Data Collection Mode

0	Screen	Toggle display screens between graphical & data analysis.
1	+cursor	Move cursor to the right by 1 bin.
2	-cursor	Move cursor to the left by 1 bin.
3	Y mag	Increase Y axis magnification.
4	Y roll	Increase Y roll (by 10%)
5	X mag	Increase X axis magnification.
6	Pause/Resume	Pause/resume integration.
7	none	no action
8	none	no action
9	Kill	Kill off integration now and flush data buffer.
10	Dark Mode	Toggle Dark mode on/off.
11	none	no action
12	Recalc. Filter	Recalculate data spike filter windows.
13	none	no action
14	End	End integration at end of pass (keep data collected so far).
15	none	no action

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PCPOLAR

USERS MANUAL

TABLE OF CONTENTS

SOFTWARE COMMANDS & LOCATIONS

INTRODUCTION

SETTING UP THE POLARIMETER

STARTING THE SYSTEM

COLLECTING DATA

Detailed Command Information

Non-Data Collection Mode

Data Collection Mode