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Summary of Contents for Unihedron SQM-LU-DL
- Page 1 SQM-LU-DL Operator’s Manual © Copyright 2005 - 2022 Version: 20220119 Company information Mailing address Unihedron 4 Lawrence Avenue Grimsby, Ontario L3M 2L9 Canada Telephone (905) 945-1197 Website unihedron.com...
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Page 3: Table Of Contents
7 Unihedron Device Manager ........ - Page 4 8.5.11 Logging Interval setting response ........Unihedron SQM-LU-DL Operator’s Manual -...
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Page 5: List Of Figures
3.1 SQM-LU-DL Block diagram ........ - Page 6 7.1 Splash screen ........... . 7.2 File menu .
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Page 7: List Of Tables
8.35 Response of setting or getting the mutual access mode ......Unihedron SQM-LU-DL Operator’s Manual -... - Page 8 8.36 Summary of standard commands ......... 8.37 Continuous reporting command summary .
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Page 9: Introduction
4. Click the “Find” button to find attached devices, then click on the SQM-LU-DL that you connected. 5. Click ”Data Logging” tab to go to the setup page. 6. Click the “Set” button in the “Device Clock” area on that page to synchronize the SQM-LU-DL internal time with your computer time and date. -
Page 10: Saving The Data Log
1 Introduction 9. Disconnect the SQM-LU-DL from the USB cord and plug in the battery pack within eight hours, the LED will come on for three seconds to indicate that the unit woke up and is working. The LED will come on every minute for a few seconds, you can use this to determine if the unit is still properly powered. -
Page 11: Measurements
2 Measurements The SQM-LU-DL provides readings in Magnitudes per square arcsecond, abbreviated as: mpsas, and written mathemat- ically 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 12: 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 Operator’s Manual - 20220119... -
Page 13: 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 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 14: 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 Operator’s Manual - 20220119... -
Page 15: Theory Of Operation
(i.e. using the “rx” command too frequently). Starting at firmware version 58, the SQM-LU-DL can provide a status of the reading that the user has requested by using the “r1x”... -
Page 16: Communication To The Pc
The micro-controller responds to commands by sending data strings to the USB interface which are then relayed to the Readings are gathered asynchronously by the micro-controller. Requests from the PC are buffered and dealt with as time permits. Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 18: Specifications
Battery pack with batteries weight 160g USB cable weight 140g Meter precision Each SQM-LU-DL 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... -
Page 19: Front And Back Of Of Unit
Figure 4.1: Front and back of of unit Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 20: Hardware Connections
5 Hardware connections The SQM-LU-DL 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 21: Diagnostic Led
M easure 5.2 Diagnostic LED When the unit is connected to a battery, the red LED near the USB connector will illuminate in the sequence shown in Figure 5.4 (firmware feature version 26 onwards): Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 22: Diagnostic Led Timing Diagram
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 Operator’s Manual - 20220119... -
Page 23: Software Development
2. Data commands are sent to the SQM-LU-DL, and it responds with a string of characters. 3. Close the serial port so that other programs can access the SQM-LU-DL. Note: Only one connection can be made to the SQM-LU-DL at a time. Therefore leaving a connection open constantly prevents other connections from being made. -
Page 24: 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 Operator’s Manual - 20220119... -
Page 25: 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. The latest version of UDM is available at the Unihedron website at this location www.unihedron.com/projects/darksky/cd/ 7.2 Installation... -
Page 26: 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 95 for possible solutions. 7.3.2 Main screen The main screen of UDM consist of the following sections: Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 27: 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 Operator’s Manual - 20220119... -
Page 28: View Menu
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 to simulate conversions of frequency and period to light meter values. See page 59 for more details. -
Page 29: View : Log
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 can be updated or reverted using UDM. These firmware files are stored at the displayed firmware files path. This path is not changeable. -
Page 30: Data Logging Header
Configfile path is the place where UDM stores its configuration about the program and attached SQM devices. This path is not changeable. View : DL Header shows the Data-logger header editing page. See the information at www.darksky.org/measurements for a detailed description of each field. Figure 7.7: Data logging header Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 31: 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. The cover offset is a text only field that indicates what offset was used on the calibration data of the SQM-LU-DL. Unihedron SQM-LU-DL Operator’s Manual -... -
Page 32: 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 Operator’s Manual - 20220119... - Page 33 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 Operator’s Manual - 20220119...
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Page 34: 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 Operator’s Manual - 20220119... -
Page 35: 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 and an external GPS are read by UDM in the Log Continuous datalogging mode. -
Page 36: 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 Operator’s Manual - 20220119... -
Page 37: 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 Operator’s Manual - 20220119... -
Page 38: 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 Operator’s Manual - 20220119... - Page 39 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 below. Unihedron SQM-LU-DL Operator’s Manual - 20220119...
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Page 40: 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 Operator’s Manual - 20220119... - Page 41 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 Operator’s Manual - 20220119...
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Page 42: Help Menu
SQM that you want to know more about. Once you select the device, then the connection details are displayed. Clicking on the “Version” or “Reading” button will gather more information from the meter. Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 43: Information Tab
The information tab is used to show information about the version and the reading of the selected SQM. Press the “Version” button for an updated list of data about the device version, and press the “Reading button” for an updated list of data about the device reading. Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 44: Log Continuous
The “Log continuous” function allows data from the connected SQM device to be logged repetitively as shown in Figure 7.26. Figure 7.26: Log Continuously screen Log Continuous Trigger options must be defined before logging, see Figure 7.27 for possibilities: Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 45: Log Continuously Trigger Tab
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). The threshold value is saved in the registry configuration file when it is changed. Changes can only be made while not recording. Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 46: Log Continuously Pre-Audio Alert
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. Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 47: Log Continuously Annotation Tab
Figure 7.33: Log Continuously GPS tab The following GPS units have been tested with the latest UDM software: Connection Settings GlobalSat BU-353 4800 baud GlobalSat BU-353 S4 (5Hz) 115200 baud Dual XGPS160 Bluetooth See GPS owners manual Unihedron SQM-LU-DL Operator’s Manual - 20220119... - Page 48 The location, speed, time, and status information is displayed as it is received. If the GPS is enabled before logging, then the logfile is forced to ”MOVING” platform mode, and five fields (latitude, longitude, elevation, speed, number of satellites in view) are appended to each record. Unihedron SQM-LU-DL Operator’s Manual - 20220119...
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Page 49: 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 Operator’s Manual - 20220119... -
Page 50: 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 Operator’s Manual - 20220119... -
Page 51: Report Interval Tab
Ideal crossover firmware: See Theory of operation section 3.1 for full details. 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. -
Page 52: Firmware Tab
3. The “Load firmware” button will be enabled and you can press it now to start loading the firmware in to the SQM-LU-DL. The status bar will indicate successful completion when the firmware has been completely loaded. When using a Mac or Linux, the firmware can be loaded/restored using the “USB comm check” method when the associated buttons appear. -
Page 53: 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 54: Data Logging Tab
Device Clock To set the RTC on the SQM-LU-DL, 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 for an updated Unit clock value. The UTC and local time are taken from the computer that UDM is running on. -
Page 55: Real Time Clock Setting Dialog
Figure 7.44: Real Time Clock setting dialog Pressing the “Set” button will copy the UTC time in to the SQM-LU-DL. Due to single second resolution, the clocks may never match within 0 seconds difference. The SQM-LU-DL clock is as accurate as a common digital watch, it may drift a few seconds per day. -
Page 56: Dl Retrieve Dialog Window
See page 30 for more information. Retrieve All Press the “Retrieve All” button to collect all recorded data points from the SQM-LU-DL unit and store to a file. Depending on the number of data-points, this action may take a long time. -
Page 57: Vector Datalogger
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. The data log window will be instantly updated with the result of your action and point to the latest record. -
Page 58: Contour Plot
• The contour plot will appear after all the points have been read in and processed which could take a long time depending on the number of recorded points. An example of the contour plot is shown in Figure 7.49. Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 59: Minimum .Dat Requirements
7.10.3 Minimum .dat requirements The Contour plot reads records from a .dat file created by retrieving data from the SQM-LU-DL. 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 60: Simulation From File
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 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 61: 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 creates a reading, of when a reading is requested (using the rx command). -
Page 62: Command Line Parameters
An example for the Windows shortcut, in the Target, put the command in quotations and add the command line parameters to the end like this example to find the USB device with USB ID 12345678 and starts logging to disk: "C: Users User AppData Local Unihedron udm.exe" -SUI,12345678 -LCR Unihedron SQM-LU-DL Operator’s Manual -... -
Page 63: Commands And Responses
8 Commands and responses The SQM-LU-DL 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. -
Page 64: Summary Of Datalogger Commands
Logging Interval period set in seconds. LPS...x Logging Interval period set in minutes. LPM...x Logging Threshold for interval reports set. LT...x Get real time clock data. Set real time clock data. LC...x Put unit to sleep. Get alarm data. Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 65: Response Details
8.2 Response details 8.2.1 Reading request The “Reading” request “rx” or “Rx” commands the SQM-LU-DL 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 66: Linear Reading Request
The format of the response is shown in table 8.5: Table 8.5: 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 Operator’s Manual - 20220119... -
Page 67: Inline Linear Reading Request
460800. 48-54 Temperature measured at light sensor in degrees C. 039.4C Leading space for positive value. Leading negative sign (-) for negative value. Table continued on next page ... Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 68: 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. The protocol version is independent of the feature version. 11-18 Model number (8 digits). -
Page 69: Light Calibration Command
0123456789 123456789 123456789 123456789 123456789 1234567 8.3.2 Light calibration command Calibration of the SQM-LU-DL 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 70: Dark Calibration Command
Calibration is done at the factory, however, in the case where calibration values must be restored or set to something else, this command allows a new calibration value to be placed into the meter. Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 71: Manually Set Light Calibration Temperature
The meter sets a time limit of 300 seconds on this value. Executing the command “zcal7#######.###x” manually sets the light calibration offset to the value specified in “#######.###”. The units are in seconds. The format of the response is shown in table: 8.14: Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 72: Manually Set Dark Calibration Temperature
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 . 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 73: Led Accessory Response Summary
1 indicates the Snow LED is On. Where m 0 indicates the Snow LED is dsiabled . 1 indicates the Snow LED is enabled. Carriage return (0x0d), Line feed (0x0a). An example response to “A5x” is: A5,0 Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 74: 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 for record capacity calculations. -
Page 75: 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 8.22 and 8.23: Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 76: Request To Return One Logged Record
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,234,1 0123456789 123456789 123456789 123456789 123 Unihedron SQM-LU-DL Operator’s Manual - 20220119... -
Page 77: Retrieve All Binary
8.5 Datalogger commands 8.5.7 Retrieve all Binary To retrieve all records from the SQM-LU-DL 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 8.24: Response to Binary Retrieve command... - Page 78 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 Operator’s Manual - 20220119...
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Page 79: Get Internal Voltage
Carriage return (0x0d), Line feed (0x0a). 8.5.10 Set and read logging trigger mode The SQM-LU-DL has the following possible modes (see table 8.28) of logging data while the external battery is being used for power: Table 8.28: Request to set the logging trigger mode... -
Page 80: 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 Operator’s Manual - 20220119... -
Page 81: Logging Interval Reporting Period Setting
8.5.13 Set and read logging Real Time Clock The SQM-LU-DL model contains a Real Time Clock (RTC) powered by a Supercap (large storage capacitor). The RTC is set with the “LCx” command as shown in table 8.31: Table 8.31: Setting the RTC... -
Page 82: Get Real Time Clock Version
012345 8.5.15 Put datalogging unit to sleep For test purposes, the SQM-LU-DL can be put to sleep with the “Lsx” command so that the quiescent battery current can be measured. The unit must be awakened by re-applying power (cold-start). 8.5.16 Gather alarm 0 data from RTC For tests purposes, the SQM-LU-DL RTC “Alarm 0”... -
Page 83: Mutual Access
0123456789 123456789 123 8.5.17 Mutual access Allows the SQM-LU-DL 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 84: 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 Operator’s Manual - 20220119... - Page 85 8.6 Continuous reporting commands Table 8.38 – continued from previous page Column Example value Description Carriage return (0x0d), Line feed (0x0a). An example response is: YrCpu 01234 Unihedron SQM-LU-DL Operator’s Manual - 20220119...
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Page 86: Setting Interval Reporting Parameters
8.7 Setting Interval reporting parameters For firmware feature 13, the SQM-LU-DL 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-DLs can be distinguished from each other. -
Page 87: 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 Operator’s Manual - 20220119... -
Page 88: Simulation Commands
When using the Simulation mode of the SQM-LU-DL, make sure that nothing else interrupts the sequence of readings such as external programs reading from the SQM-LU-DL, or settings of Interval reporting inside the SQM-LU-DL. To read the internal simulation values, issue the “sx” command, the response is shown in table 8.41: Table 8.41: Response of request for internal simulation values... -
Page 89: 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 Operator’s Manual - 20220119... -
Page 90: 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 91: Cover Maintenance
9.1 Mechanical installation 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 Operator’s Manual - 20220119... -
Page 92: Default Settings
The SQM-LU-DL 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. -
Page 93: Firmware Upgrade
11 Firmware upgrade See the UDM “Firmware tab” section on page 52 for instructions on updating the firmware in the SQM-LU-DL. 11.1 Details The SQM-LU-DL contains a micro-controller that is equipped with a boot-loader mechanism which is enabled for a few seconds after reboot/reset. -
Page 94: 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. The light calibration routine inside the SQM-LU-DL expects to see this value. -
Page 95: 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 96: Usb Serial Number Garbled
• Remove any other USB devices attached to the system to troubleshoot this problem. • Try to reassign the SQM-LU-DL to another COM port using the Windows Device Manager. For example, it the SQM-LU-DL is assigned to COM1, then try to assign it to a free COM port number. -
Page 97: 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 Operator’s Manual - 20220119... -
Page 98: 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, 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 99: 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 has been assigned. If the SQM-LU-DL is plugged in, the active COM port will show up in this list: HK LOCAL MACHINE... -
Page 100: Glossary
This type of memory has a limited write/erase cycle as well as a lifetime for data retention. In the SQM-LU-DL, the parameters in the micro- controller can be written 1 million times and last for 100 years. -
Page 101: Bibliography
[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¨...
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