Unihedron SQM-LU-DL-V Operator's Manual

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SQM-LU-DL-V

Operator's Manual

Version: 20240701

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Page 1 SQM-LU-DL-V Operator’s Manual © Copyright 2005 - 2024 Version: 20240701 Company information Mailing address Unihedron 4 Lawrence Avenue Grimsby, Ontario L3M 2L9 Canada Telephone (905) 945-1197 Website unihedron.com...
Page 3: Table Of Contents
7 Unihedron Device Manager ........
Page 4 Logging capacity report ......... . Unihedron SQM-LU-DL-V Operator’s Manual -...
Page 5 14 Glossary ............124 Unihedron SQM-LU-DL-V Operator’s Manual -...
Page 6: List Of Figures
3.1 SQM-LU-DL-V Block diagram ........
Page 7: List Of Tables
7.28 Information tab ........... 7.29 Log Continuously screen .
Page 8 8.52 Interval report ........... 109 Unihedron SQM-LU-DL-V Operator’s Manual -...
Page 9 8.53 Response of viewing or setting interval reporting parameters ......110 8.54 Response of request for internal simulation values ....... . 111 8.55 Request simulation (S..x) .
Page 10: Introduction
• Researching twilight brightness changes with the addition of external Neutral Density filters. Unihedron offers adapters to attach such filters onto the meter. • The SQM-LU-DL-V has the same features as the SQM-LU with the addition of data logging and vector measurement capabilities.
Page 11: Saving The Data Log
“every 5 minutes”. 10. Keep the SQM-LU-DL-V connected to the computer for a couple of hours to charge up the internal Supercap; this allows it to keep the time and date clock running while you are moving from your computer to the measurement site.
Page 12: Handheld Battery Pack
7. The Zenith level display shows a “bubble” style level gauge that is centered when the meter is point at the Zenith. 8. Press the “Monitor” toggle button OFF. 9. You can close the calibrate dialog to go back to normal UDM operation. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 13: Other Software
• The CD contains examples of software (Perl, Python, etc.) for various functions that connect to the meter. 1.1.6 FITS integration Some programs (listed below) gather information from the Unihedron Sky Quality meter products and insert that data into the Flexible Image Transport System (FITS) header.
Page 14: Measurements
2 Measurements The SQM-LU-DL-V provides readings in Magnitudes per square arcsecond, abbreviated as: mpsas, and written mathe- matically as arcsec Mpsas is a logarithmic measurement which means that large changes in sky brightness correspond to relatively small numerical changes. A difference of 5 magnitudes is a factor of 100 times the intensity. Therefore a sky brightness 5.0 arcsec darker corresponds to a reduction in photon arrival rate of a factor of 100.
Page 15: Getting Accurate Readings
Undesirable artificial light that reaches you is considered to be light pollution. Much of this light comes from outdoor illumination of parking lots, street lamps, office buildings, advertising signs, etc.. Other causes of extra light in the night sky are listed below: Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 16: Other Luminance Scales
The Milky Way As one goes to sites with darker surface brightnesses, the fraction of the total light received by the SQM-LU-DL-V which can be attributed to the Milky Way bulge increases and so the “offset” in mpas will be larger (due to the Milky Way.) The northern view of the Milky Way contributes about 0.10 mpsas under 21.5 mpsas (moonless) skies.
Page 17: Mpsas Vs Nelm
NSU values indicate how much brighter or darker the sky is compared to a typical historic clear night sky. It is defined 0.4∆ here as N SU = 10 where ∆ is 21.6 minus the observed value in magSQM/arcsec Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 18: Theory Of Operation
(i.e. using the “rx” command too frequently). Starting at firmware version 58, the SQM-LU-DL-V can provide a status of the reading that the user has requested by using the “r1x”...
Page 19: Altitude (Inclination) Measurement
(like a metal tripod or the battery pack). The battery pack included with the the SQM-LU-DL-V has steel connections which are magnetized enough to affect the reading if placed too close to the meter’s internal compass module. Place the battery pack as far as possible from the meter.
Page 20: Specifications
Battery pack with batteries weight 120g USB cable weight 140g Meter precision Each SQM-LU-DL-V is factory-calibrated. The absolute precision of each meter is believed to be ±10% (±0.10 mag/arcsec ). The difference in zero-point between each calibrated meter is typically ±10% (±0.10 mag/arcsec Power requirement 18mA (from the 5V USB connection).
Page 21: Hardware Connections
5 Hardware connections The SQM-LU-DL-V requires one connection to a USB hub or a PC for configuring the device and recovering the readings as shown in Figure 5.1. Figure 5.1: Wired connection The maximum length cable per the USB specification is 15ft (3m). USB extenders exist on the market, some work up to 198ft (60m).
Page 22: Solar Charger
”measure” state, and I still applies. M easure 5.1.1 Solar charger When using the solar charger with NiMH batteries, the batteries will be charged during sunlight hours, and the measured battery voltage will be recorded. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 23: Diagnostic Led
D Wake from sleep at the minute mark to check if a recording should be logged. The LED comes on bright then fades off within one second. Firmware before feature 49 had this step leave the LED on for three seconds solid. E Same as step C. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 24: Software Development
FTDI software drivers which are available for all major operating system platforms. Drivers are available from www.ftdichip.com . Once the driver is installed, commands can be sent to the SQM-LU-DL-V using a serial terminal emulator to the serial communications port that the device routes to.
Page 25: Pascal
The UDM program contains many examples of finding the SQM devices and reading data from them. It is open source and written in Lazarus/FreePascal. The source files for UDM are available here: unihedron.com/projects/darksky/cd/udm/ . Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 26: Unihedron Device Manager
• Setup and retrieve data from datalogging meters. • Continuously log data from connected meters. 7.1 Getting UDM UDM is supplied on the CD that shipped with the SQM-LU-DL-V. The latest version of UDM is available at the Unihedron website at this location www.unihedron.com/projects/darksky/cd/ 7.2 Installation...
Page 27: Operation
USB device listing for your operating system. These USB devices should appear as a COMM port. Also, check the troubleshooting notes in section 13 on page 119 for possible solutions. 7.3.2 Main screen The main screen of UDM consist of the following sections: Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 28: Main Menu
The file menu is used for: opening files, finding newly attached devices, and quitting the program as shown in Figure 7.2. Figure 7.2: File menu File : Open The “File : Open” menu item is used to open up previously stored log files or calibration reports. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 29: View Menu
The program can also be closed from the window panel “X”. 7.3.5 View menu The view menu allows you to enable various tabs and check other settings of the UDM program. Figure 7.4: View menu Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 30: View : Log
Click on “View : Simulation” to toggle visibility of the “Simulation” tab. The Simulation tab can be used to send requests to the SQM-LU-DL-V to simulate conversions of frequency and period to light meter values. See page 72 for more details.
Page 31: Data Logging Header
UDM and stored at the displayed “TZ database path”. This path is not changeable. The Time Zone database is taken from: http://www.twinsun.com/tz/tz-link.htm Firmware files path The firmware for the SQM-LU-DL-V can be updated or reverted using UDM. These firmware files are stored at the displayed firmware files path. This path is not changeable.
Page 32: Set Location Dialog
The “Local timezone region” and “Local timezone name” are required by UDM to calculate local times of the recorded data before storing to disk. UTC timestamps are stored in the SQM-LU-DL-V. The cover offset is a text only field that indicates what offset was used on the calibration data of the SQM-LU-DL-V. Unihedron SQM-LU-DL-V Operator’s Manual -...
Page 33: Plotter Window
• Settings: Display: Grid, and Darkness only, all other display selections can be unchecked. • Select Plot number: 1, then click on the reference file (with the correct timing). • Select Plot number: 2, then click on the problem file. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 34 The width of a line is defined with an integer number of pixels, for example: MPSASWidth=3 The following names can be used to define plot line widths: MPSASWidth MPSAS2Width MPSAS3Width MoonWidth SunWidth CivilWidth NauticalWidth AstronmicalWidth SunTwilightWidth VoltageWidth TemperatureWidth Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 35: Tools Menu
Figure 7.11: Tool : dat to Moon csv Press the “Select ...” button shown in Figure 7.11 to select the file and start the conversion process. You may also be interested in the “Excel import” instructions listed in section 7.5.1. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 36: Tool : Comm Terminal
The “DL retrieve” tool is used for datalogging and Vector model to pull in data files that were stored on disk previously. Tools : .dat to .kml Creates a .kml file from a .dat file. This is used when the SQM-LU-DL-V and an external GPS are read by UDM in the Log Continuous datalogging mode.
Page 37: Tool : .Dat To .Kml Googleearth Result
This may be useful when the battery has expired in the datalogging meter, or if the clock was not set at the beginning of the datalogging session. Figure 7.15: Tool : .dat time correction Select the .dat file for correction. Enter the manual time offset correction (in seconds). Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 38: Tool : .Dat Local Time Reconstruction
If the real-time-clock inside the datalogger was not set properly or the battery was not plugged into the datalogger quickly enough to keep the super-capacitor charged before datalogging began, then there would be a difference in time when the data was retrieved. The .dat file can be corrected with this tool. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 39: Dat To Sun-Moon-Mw-Clouds Values
Milky Way Arc; value of zero implies the SQM is pointed directly into the Milky Galactic Lat Angle in degrees from the Galactic Center (Sagittarius) eastward along the Galactic Galactic Long equator Days since January 1, 2000; fractional J2000days Table continued on next page ... Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 40 This cloud estimation algorithm fits a linear regression to the SQM data over a time range. and calculates the Residual Standard Error (RSE), a measure of the fit between the linear regression and the actual SQM data. See Figure 7.17. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 41: Rse Algorithm
1. If the Latitude and Longitude are not specified in the input .dat file, processing will stop. 2. If the Location name is not specified in the input .dat file, the location name will be printed in the output .csv file as “Not-Specified”. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 42 4. The first Range number of points in a day and the final Range number of points in a day are assigned dummy RSE values of 999000.0 5. During daylight hours when the entire Range of values has SQM readings of 0.0, the RSE values is reported as 0.0 Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 43 SQM; that FOV is nominally 20 degrees; we suggest a 30-degree cutoff as a conservative approach. This one value is applied symmetrically on the positive and negative size of the zenith. Choose parameter value of zero to prevent exclusion of data records on the basis of the galactic latitude. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 44 Milky Way, max MPSAS allowed and sparse cutoff filters - i.e. “dense” data which represents the most commonly occurring data at an SQM site; this file has the same format at the input .csv file Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 45 The goal of the sparseness filter is to remove the data points that plot away from the most dense data, to avoid bias of measurement of the clear night sky brightness. See Figure 7.19 Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 46 7 Unihedron Device Manager Figure 7.19: Same data as Figure 7.18, but after application of the sparseness filter. The remaining data can provide a good estimate of the night sky brightness at this SQM location. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 47 Figure 7.20: Diagram of the sparseness filter. Blue squares represent SQM measurements acquired under infrequent overcast or foggy conditions. The goal of the sparseness algorithm is to identify them for segregation into the “Sparse” output csv file. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 48: Help Menu
Help : Online resource links to the updated online Unihedron resource files that are sent out with each meter. Help : Cmdline Info shows the commands that can be used when starting UDM from the command line.
Page 49: Information Tab
The RS232 fields are editable so you may enter your own port and baud rate. The baud rate for the SQM-LR is 115200. See Figure 7.27. Figure 7.27: RS232 connection details 7.4 Information tab The information tab is used to show information about the version and the reading of the selected SQM. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 50: Log Continuous
“File : Open” menu. 7.5 Log Continuous The “Log continuous” function allows data from the connected SQM device to be logged repetitively as shown in Figure 7.29. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 51: Log Continuously Screen
7.5 Log Continuous Figure 7.29: Log Continuously screen Log Continuous Trigger options must be defined before logging, see Figure 7.30 for possibilities: Figure 7.30: Log Continuously Trigger tab Figure 7.31: Log Continuously Look tab Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 52: Log Continuously Status Tab
A threshold of 0 will allow all readings to be recorded. The threshold indicator will turn green if the threshold of the triggered reading is met (recording) and red if the triggered reading is below the threshold (no recording). Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 53: Log Continuously Alerts
Directory (which can be identified from the main page View Directories). Figure 7.35: Log Continuously Alarm for darkness Transfer reading Each reading can be sent by TCP to an external destination (remote) server. Figure 7.36: Log Continuously Transfer reading Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 54: Log Continuously Transfer Tab
You will have to copy the public key etc. to make a passwordless connection. • SFTP (Secure File Transfer Protocol) assumes that the sftp command exists. This is not available for Windows at this time. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 55: Log Continuously Annotation Tab
Annotation settings While the “Log Continuous” mode is recording data, annotations can be made to the log file records with hotkeys. The Annotation tab allows the definition of hotkeys and their associated annotation text that will appear at the end of an annotated record. Figure 7.38: Log Continuously Annotation tab Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 56: Log Continuously Gps Tab
6. Enter the Comm Port into the Port: field, in my case I just typed in COM6 7. Enter the baud rate for the GPS into the Baud: field, in my case I just typed in 115200 Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 57 On a Mac, you can use Finder to go to “Applications”, then right click on “udm” or “udm.app” then select “Show contents”. Then you can navigate to Contents Resources to see the location of the *.goto file(s). Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 58: Import.dat Into Spreadsheet
12. field 1,2 = date YMD Note: You can also use the “.dat to Moon .csv” tool shown in Fig. 7.11 to create a comma separated variable file for importing into a spreadsheet like Excel. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 59: Calibration Tab
3. The value is sent to the SQM, and then confirmed in the right side box (Actual values column). Note that temperatures set in to the SQM use their own resolution and may not be reflected as the same value entered. For example. 24.7°C might read back as 24.8 °C. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 60: Report Interval Tab
7 Unihedron Device Manager The original factory calibration values were provided on a paper with the shipped unit. If you have lost this information, please contact Unihedron to have the information emailed. 7.7 Report Interval tab The Report Interval tab is used to show and set the report interval information for the selected SQM. Report interval settings are used to control the SQM to send readings out at a regular rate (in seconds) and only if darker than a specified threshold value.
Page 61: Firmware Tab
7.8 Firmware tab 7.8 Firmware tab In a case where new firmware is supplied by Unihedron to correct bugs or add features, use this tab to select and load firmware in to the SQM-LU-DL-V. All available versions of firmware are shipped with the UDM software package in case you want to revert to an earlier firmware version for testing purposes.
Page 62 2. Have the meter connected 3. Go to the firmware tab 4. Select the appropriate firmware like SQM-LU-DL-4-6.67.hex 5. Press the ”START UNPLUG METHOD button 6. Follow the instructions shown on the right side of the button. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 63: Data Logging Tab
Mutual access logging The default, “Battery only logging” mode allows triggered logging while connected to the battery pack where there are no data wires (only power wires) connected to the USB jack. In this mode, the SQM-LU-DL-V will not log readings to its internal FLASH memory while connected to the PC.
Page 64: Data Logging: Mutual Access Logging Selection
Device Clock To set the RTC on the SQM-LU-DL-V, press the “Device Clock” button to call up the “Real Time Clock” dialog. While the RTC dialog is shown, UDM continuously polls the SQM-LU-DL-V for an updated Unit clock value.
Page 65: Storage Navigation Button Descriptions
Retrieve Press the “Retrieve” button to call up the “Retrieve” dialog shown in Figure 7.50. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 66: Dl Retrieve Dialog Window
Header The “Header” button calls up the details that are stored on the computer when a data-logger data is retrieved and written to disk. See page 31 for more information. The definitions of the header fields can be seen from the link in the header screen. Some extra definitions of retrieved fields: Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 67: Extra Definitions Of Retrieved Fields
Retrieve All Press the “Retrieve All” button to collect all recorded data points from the SQM-LU-DL-V unit and store to a file. Depending on the number of data-points, this action may take a long time.
Page 68: Dl Erase Dialog Window
Cancel Retrieve Press the “Cancel Retrieve” button to cancel a “Retrieve All” or ”Retrieve range” action. Log one Press the “Log one” button to record a single record in the data log memory of the SQM-LU-DL-V. The data log window will be instantly updated with the result of your action and point to the latest record.
Page 69: Vector Datalogger
7.10 Vector datalogger 7.10 Vector datalogger The SQM-LU-DL-V can be setup for an all-sky survey of brightness data points. Refer to Figure 7.52 for key points. Figure 7.52: Datalogging page for vector model 7.10.1 Contour plot Follow these steps to see a contour plot of the retrieved data: •...
Page 70: Minimum .Dat Requirements
7.10.2 Minimum .dat requirements The Contour plot reads records from a .dat file created by retrieving data from the SQM-LU-DL-V. You can use other methods to generate the Altitude and Azimuth field and make up a .dat file yourself. The minimum requirements for the .dat file to be read by the contour plotting function are:...
Page 71: Configuration Tab
The “Configuration tab” shows the factory-set calibration values. Calibration is performed at the Unihedron factory. A new calibration using a calibrated light source and darkroom can be performed by following the instructions on the right side of the screen. The calibration report can be logged to a data file and also printed out from this screen.
Page 72: Simulation Tab
The “Simulation” tab allows the simulation of raw light sensor values for experimentation purposes. The “Start” button initiates feeding the range of values to the internal formulas of the SQM-LU-DL-V and results are displayed on this tab. Raw temperature conversions are detail in Eq: 8.1 and 8.2. The simulation will stop once all the steps are complete or when the “Stop”...
Page 73 7.12 Simulation tab Listing 7.3: simout.csv example # Simulation from file. # UDM version: 1.0.0.43 # Unit information cx: i,00000004,00000003,00000032,00000704 # Calibration cx: c,00000019.80m,0000107.511s, 028.3C,00000008.71m, 029.3C S,0000000000c,0000568380f,0000000232t,r, 00.00m,0000568380Hz,0000000000c,0000000.000s, 024.8C S,0000072970c,0000000006f,0000000196t,r, 17.79m,0000000006Hz,0000072970c,0000000.158s, 013.2C Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 74: Accessory Options
The LED draws current and it may not be desireable to enable it when operating from the battery pack. The LED blinks for 1/60th of a second. The LED can blink either when the SQM-LU-DL-V creates a reading, of when a reading is requested (using the rx command).
Page 75: Command Line Parameters
Find button to find devices. Display plotter window. -TCA Start up Concatenate/Analyze tool -TCM Start up Cloud removal / Milky way position tool Table continued on next page ... Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 76: Internal Startup Options
To get Windows to open up UDM at startup: • Select the Start button and scroll to find the Unihedron Device Manager app that you want to run at startup. • Right-click the app, select More, and then select Open file location. This opens the location where the shortcut to the app is saved.
Page 77: Mac Autostartup
5. Enter the desired start time 6. Select Start a program 7. Click on browse to find the program which is usually located at "C: Users User AppData Local Programs Unihedron udm.ex 8. For SQM-LE, Enter additional parameter: -SEM, -LCM, -LCR...
Page 78: Commands And Responses
8 Commands and responses The SQM-LU-DL-V accepts a sequence of characters as a command, then executes those commands and usually provides a response of a sequence of characters. The following details are useful when programming your own interface to send data to and receive data from the SQM-LU-DL-V.
Page 79: Summary Of Datalogger Commands
Magnetic readings. Acceleration readings. v3. . . x Save/Get Acceleration calibration (v3x or v3,-12345, ...x or v3, 12345, ... x). v4. . . x Save/Get Magnetic calibration. Vibration report. Get Vibration threshold. Set Vibration threshold. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 80: Response Details
8.2 Response details 8.2.1 Reading request The “Reading” request “rx” or “Rx” commands the SQM-LU-DL-V to provide the current darkness value as well as all variables used to generate that result. Readings produced by this request are averaged internally by using the last 8 readings and shifting those values through an 8 cell buffer then summing and dividing by 8.
Page 81: Linear Reading Request
The format of the response is shown in table 8.6: Table 8.6: Linear reading request response Column Example value Description Indicates that a frequency reading is being returned. Table continued on next page ... Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 82: Inline Linear Reading Request
Period of sensor in counts. Counts occur at a rate of 460.8 kHz 0000000020c (14.7456MHz/32). 35-46 Period of sensor in seconds with millisecond resolution. Determined 0000000.000s by dividing the above counts value by 460800. Table continued on next page ... Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 83: Unit Information
Protocol number (8 digits). This will always be the first 8 char- 00000002 acters (after the “i,” response). This value indicates the revision number of the data protocol to/from the SQM-LU-DL-V. The pro- tocol version is independent of the feature version. 11-18 Model number (8 digits).
Page 84: Calibration Commands
0123456789 123456789 123456789 123456789 123456789 1234567 8.3.2 Light calibration command Calibration of the SQM-LU-DL-V is done at the factory in a controlled light and temperature environment. Executing the Light calibration command “zcalAx” arms the light calibration mode. A calibrated light source of approximately 13.5fc is supplied to the sensor.
Page 85: Dark Calibration Command
The format of the response is shown in table 8.12: Table 8.12: Disarm calibration response Column Example value Description Calibration response is being returned. Indicates “All” calibration modes. Disarmed. Table continued on next page ... Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 86: Manually Set Light Calibration Offset
Note: The meter records the temperature in a raw value with different resolution, so the reply back may not be exactly the same as the value sent. The format of the response is shown in table: 8.14: Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 87: Manually Set Dark Calibration Time Period
Note: The meter records the temperature in a raw value with different resolution, so the reply back may not be exactly the same as the value sent. The format of the response is shown in table: 8.16: Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 88: Snow Led Accessory
8.4 Snow LED accessory An LED used for determining snow cover on the meter can be attached to an internal pin of the SQM-LU-DL-V . This LED shines green light out of the meter and the light sensor will see a reflection if snow is covering the meter (housing cap).
Page 89: Datalogger Commands
8.5.1 FLASH ID report The FLASH memory chip stores all the data logging records. It does not contain any calibration information. The ID report is useful for determining the exact model of FLASH device inside the SQM-LU-DL-V for record capacity calculations.
Page 90: Logging Capacity Report
Carriage return (0x0d), Line feed (0x0a). An example response is: L3,0000000000 0123456789 1235 8.5.6 Return one logged record To get one entire record, use the ‘L4...x” command. The request and response are as shown in table 8.23 and 8.24: Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 91: Request To Return One Logged Record
Available on firmware feature 49 and above. 2char Available on models with snow LED. 0 = No snow data recorded. 1 = Snow data recorded. Available on firmware feature 66 and above. Table continued on next page ... Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 92 ,1234567890 Snow linear luminance value. The linear value is computed similarly to the standard linear value described above. last two Carriage return (0x0d), Line feed (0x0a). An example response is: L4,11-01-06 5 11:51:00,10.44, 023.8C,234,-02790,-01013,17053,01084,00301,-02748,00214,1 Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 93: Retrieve All Binary
8.5 Datalogger commands 8.5.7 Retrieve all Binary To retrieve all records from the SQM-LU-DL-V faster than the “Return One logged record method”, you can use this faster binary method. Thr first command sent “L8x” returns the packet length, and number of packets to be sent. The response to this first command is below: Table 8.25: Response to Binary Retrieve command...
Page 94 Snow reading; Big endian raw 32 bit binary value for magnitudes. The decimal reading value is determined as: xxxx Reading M P SAS 6553600.0 24-27 (Optional snow accessory) xxxx Snow frequency, Big endian 32 bit value. 28-31 FFFFFFFFhex Spare four bytes. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 95: Get Internal Voltage
Carriage return (0x0d), Line feed (0x0a). 8.5.10 Set and read logging trigger mode The SQM-LU-DL-V has the following possible modes (see table 8.29) of logging data while the external battery is being used for power: Table 8.29: Request to set the logging trigger mode...
Page 96: Logging Interval Setting Response
0000000005m 27-37 Current interval period in seconds from RAM 0000000121s 39-49 Current interval period in minutes from RAM 0000000004m 51-62 Threshold value that was set into RAM 00000017.60m Table continued on next page ... Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 97: Logging Interval Reporting Period Setting
The RTC is read with the “Lcx” command. The response of both setting and getting the RTC value is shown in table 8.33: Table 8.33: Response of getting the RTC values Column Example value Description Confirmation of setting command. Table continued on next page ... Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 98: Get Real Time Clock Version
Table 8.35: Response of getting the RTC “Alarm 0” value Column Example value Description Confirmation of command. Address 07H, Seconds 000, “DS1305N"+ RTC chip information for details. 7-10 Address 08H, minutes. 128, 11-14 Address 09H, hours. 128, Table continued on next page ... Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 99: Mutual Access
0123456789 123456789 123 8.5.18 Mutual access Allows the SQM-LU-DL-V to log to its FLASH memory database while connected to a PC as well as while connected to the battery pack. The default is to only allow triggered logging while connected to the battery pack where there are no data wires (only power wires) connected to the USB jack.
Page 100: Vector Commands
8 Commands and responses 8.6 Vector commands The SQM-LU-DL-V uses the Pololu 2127 accelerometer/magnetometer module which contains an STMicroelectronics LSM303D digital 3-axis accelerometer and 3-axis magnetometer module. This module provides vector measurement capabilities of Altitude (inclinometer) and Azimuth (compass) readings.
Page 101: Acceleration Calibration Values
8.6 Vector commands 8.6.3 Acceleration calibration values The acceleration portion of the acceleration/magnetometer module has a set of values when the SQM-LU-DL-V is posi- tioned in the six possible level directions (three axis, each facing upwards and downwards). Calibration is performed by...
Page 102: Vibration
An example response to “v4x” or “v4,-03102,-03226,-02937, 03502, 03556, 03246x” is: v4,-03102,-03226,-02937, 03502, 03556, 03246 8.6.5 Vibration Vibration is determined inside the SQM-LU-DL-V by computing the maximum absolute difference of all three acceleration axis over a sampling of the last 4 times each of a second apart.
Page 103: Accessories Commands
8.7 Accessories commands Some I C accessory devices can be connected to the SQM-LU-DL-V when using firmware feature version 44 and above. These devices are connected by way of retrofitted wiring inside the unit or a future back panel connector.
Page 104: Display Accessory
C 4-digit 7-segment display made by Sparkfun (model COM-11441) can be connected. All commands (seen in table 8.43) to this accessory result in a response (seen in table 8.44). Readings that are too bright for the SQM-LU-DL-V will show up as . Readings that are too dark for the meter will show up as Table 8.43: Display accessory command summary...
Page 105: Led Accessory
8.7 Accessories commands 8.7.3 LED accessory The LED at the back of the SQM-LU-DL-V is used for this built-in accessory. All commands (seen in table 8.45) to this accessory result in a response (seen in table 8.46). Using the LED to indicate when a reading is being requested is an ideal method to determine if the controlling software is actually accessing the SQM-LU-DL-V.
Page 106: Relay Accessory
8.7.4 Relay accessory A Solid State Relay (SSR) accessory may be connected to the SQM-LU-DL-V for generic use or for purposes of imple- menting a dew-heater control. All commands (seen in table 8.47) to this accessory result in a response (seen in table 8.48).
Page 107: Continuous Reporting Commands
= Ideal crossover firmware code disabled. P = Continuous reporting compression enabled. p = Continuous reporting compression disabled. U = Continuous reporting un-averaged readings enabled. u = Continuous reporting un-averaged readings disabled. Table continued on next page ... Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 108 8 Commands and responses Table 8.51 – continued from previous page Column Example value Description Carriage return (0x0d), Line feed (0x0a). An example response is: YrCpu 01234 Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 109: Setting Interval Reporting Parameters
8.9 Setting Interval reporting parameters For firmware feature 13, the SQM-LU-DL-V is capable of sending timed interval reports. Each interval report is the same as the reading request report except that the serial number (feature 14) is attached at the end so that numerous reporting SQM-LU-DL-Vs can be distinguished from each other.
Page 110: Interval Setting Response
Threshold value that was set into EEPROM. 00000017.60m 39-50 Threshold value that was set into RAM. 00000017.60m 51-52 Carriage return (0x0d), Line feed (0x0a). An example response is: I,0000000360s,0000000360s,00000017.60m,00000017.60m 0123456789 123456789 123456789 123456789 123456789 12 Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 111: Simulation Commands
When using the Simulation mode of the SQM-LU-DL-V, make sure that nothing else interrupts the sequence of readings such as external programs reading from the SQM-LU-DL-V, or settings of Interval reporting inside the SQM-LU-DL-V. To read the internal simulation values, issue the “sx” command, the response is shown in table 8.54: Table 8.54: Response of request for internal simulation values...
Page 112: Response Of Setting Simulation Values (S
Calculated period from counts. 0000000.204s, 86-92 Temperature used for calculation. 029.0C 93-94 Carriage return (0x0d), Line feed (0x0a). An example response is: S,0000094000c,0000000000f,0000000245t,r, 18.04m,0000000000Hz,0000094000c,0000000.204s, 029.0C 0123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789 123456789 1234 Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 113: Installation
Source of scrylic domes: www.globalplastics.ca/domes.htm 9.1.2 Cover calibration Since the meter is not weather-proof, it must be protected in some way from the elements. The Unihedron meter housing or a plastic dome is recommended. This will reduce the incoming light (approximately 15-20%).
Page 114: Cover Maintenance
19.77. European users will see and use a comma instead of a decimal point (eg. 19,77). Figure 9.2: Example cover calibration 9.1.3 Cover maintenance Keep the covering clean of dust, water, ice, and bird droppings. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 115: Default Settings
The SQM-LU-DL-V contains an FTDI USB interface module. The FTDI interface has not been altered from its default. There should be no reason to alter the FTDI chip settings. The baud rate is defined by the VCP driver side when a terminal program connects to the SQM-LU-DL-V.
Page 116: Firmware Upgrade
11 Firmware upgrade See the UDM “Firmware tab” section on page 61 for instructions on updating the firmware in the SQM-LU-DL-V. 11.1 Details The SQM-LU-DL-V contains a micro-controller that is equipped with a boot-loader mechanism which is enabled for a few seconds after reboot/reset.
Page 117: Calibration
A fluorescent light or green LED is used to simulate the spectrum that the meter would see during the night sky. A light meter is used to adjust the light reading to 13.5 fc at the place of the SQM-LU-DL-V. The light calibration routine inside the SQM-LU-DL-V expects to see this value.
Page 118: Altitude And Azimuth Calibration
12 Calibration 12.5 Altitude and Azimuth calibration See section 8.6.3 on page 101 for details on calibrating the Altitude and Azimuth module. Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 119: Troubleshooting
Microsoft Edge has protections in place to hide file lists on remote drives. Solution Use the File Manager to navigate the CD to the Windows directory then install from there. Or, get the latest Windows version of UDM from the Unihedron website: unihedron.com/projects/darksky/cd/Windows/ Table 13.4: Driver not found...
Page 120: Usb Device Not Found, Or More Than One Device On The Same Com Port
• Remove any other USB devices attached to the system to troubleshoot this problem. • Try to reassign the SQM-LU-DL-V to another COM port using the Windows Device Manager. For example, it the SQM-LU-DL-V is assigned to COM1, then try to assign it to a free COM port number.
Page 121: Meter Cannot Be Found On Battery Or By Pc
UDM improperly lists devices under the Windows operating system as duplicates COM ports. Cause The registry entries for the FTDI driver COM port assignments may be messed up. Table continued on next page ... Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 122: Meter Cannot Be Found By Windows Operating System
4. Re-connect one FTDI device after the other. Table 13.11: Meter cannot be found by Windows operating system Problem The windows computer cannot identify the SQM-LU-DL-V, and re-installing the FTDI device drivers does not help. Cause The Windows FTDI driver installation may be storing old attempts at installing drivers that should have been cleared out.
Page 123: Darkroom-Bag Readings Incorrect
The Serial Number is printed on the bottom of the unit. The above will identify which COM port the SQM-LU-DL-V has been assigned. If the SQM-LU-DL-V is plugged in, the active COM port will show up in this list: HK LOCAL MACHINE...
Page 124: Glossary
Vetcor measurements Altitude (inclinometer) and Azimuth (compass). Supercap A very large capacitor in the order of Farads. The SQM-LU-DL-V uses a supercap to keep the RTC running when the meter is not connected to any external power supply. The advantage of this component no internal battery must be regularly replaced.
Page 125 Unihedron SQM-LU-DL-V Operator’s Manual - 20240701...
Page 126 [4] Olof Carlin, Nils. About Bradley E. Schaefer, Telescopic limiting Magnitudes, Web page discussion of brightness in Schaefer (1990) and Clark (1994). http://w1.411.telia.com/ ~ u41105032/visual/Schaefer.htm(accessed7/ 2003) [5] NELM Converter, K. Fisher fisherka@csolutions.net Rev. 8/2006 http://unihedron.com/projects/doug/darksky/ NELM2BCalc.html [6] Moon Phase Pascal code in UDM is from the public domain library: Moon.pas Copyright 1997-2001 Andreas H¨...