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

Hide thumbs Also See for SQM-LU-DL-V:

Operator's manual (126 pages)

Table of Contents

Quick Links

Download this manual

SQM-LU-DL-V

Operator's Manual

Version: 20211013

Need help?

Do you have a question about the SQM-LU-DL-V and is the answer not in the manual?

Questions and answers

Summary of Contents for Unihedron SQM-LU-DL-V

Page 1 SQM-LU-DL-V Operator’s Manual © Copyright 2005 - 2021 Version: 20211013 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 Get internal voltage ..........Unihedron SQM-LU-DL-V Operator’s Manual -...
Page 5 8.5.9 Get EEPROM status register 1 ........8.5.10 Set and read logging trigger mode .
Page 6: List Of Figures
5.3 Current proﬁle ........... 5.4 Diagnostic LED timing diagram for SQM-LU-DL-V ......
Page 7: List Of Tables
7.34 Calibration tab (populated) ..........7.35 Report interval tab .
Page 8 8.17 LED accessory command summary ........8.18 LED accessory response summary .
Page 9 8.2 degC to Raw Temperature ..........Unihedron SQM-LU-DL-V Operator’s Manual -...
Page 10: Introduction
5 minutes”. 8. 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...
Page 11: Saving The Data Log
1.1 QuickStart 9. Disconnect the SQM-LU-DL-V 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 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 - 20211013...
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 - 20211013...
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
= 21.58 log(10 (2.2) mpsas Convert MPSAS (B) sky brightness to NELM (V mags) [4] (4.316 (Bmpsas/5)) N ELM = 7.93 log(10 + 1) (2.3) A newly proposed term to deﬁne “Natural Sky Units”: Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 18 21 (galactic center near zenith) to 24 mag/arcsec2 (very thick clouds), or 0.1 - 1.7 NSU.[1] Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 19: 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 20: 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 21: 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...
Page 22: 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 23: 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 ?? (ﬁrmware feature version 26 onwards): Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 24: Diagnostic Led Timing Diagram For Sqm-Lu-Dl-V
5 Hardware connections Figure 5.4: Diagnostic LED timing diagram for SQM-LU-DL-V Description of LED ﬂashes: A On for three seconds during the power-up/boot-load sequence. During this time, the unit is supplying power to the sensor components and will also accept ﬁrmware updates.
Page 25: 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 26: 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 - 20211013...
Page 27: 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 28: 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 98 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 - 20211013...
Page 29: 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 - 20211013...
Page 30: 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-V to simulate conversions of frequency and period to light meter values. See page 57 for more details.
Page 31: 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-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: 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-V Operator’s Manual - 20211013...
Page 33: 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 34: 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 - 20211013...
Page 35 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 - 20211013...
Page 36: 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 - 20211013...
Page 37: 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 38: 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 - 20211013...
Page 39: Help Menu
Help : Cmdline Info shows the commands that can be used when starting UDM from the command line. Help : Version Info shows the detailed version information for the UDM software. Help : About displays a simple screen with the version identiﬁer. Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 40: Help : About
Device details shows the connection details of the selected SQM listed in the “Found devices” box. The USB “Port” ﬁeld is editable so you may enter your own port that might not be deﬁned in the found box. See Figure 7.21. Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 41: Information Tab
The Header button calls up the data ﬁle header entry screen, see the datalogging Header section on page 32 for more information. This header information is used when storing logged data to the disk with the “Log one record” or “Log Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 42: Log Continuous
Log Continuous Trigger options must be deﬁned before logging, see Figure 7.26 for possibilities: Figure 7.26: Log Continuously Trigger tab To operate the continuous logging function: 1. Select the frequency of logging from the trigger tab. Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 43: Log Continuously Threshold
Alarm for darkness When the darkness is over the threshold amount, an audio ﬁle can be enabled to play (Fig. 7.29) . The Test button plays this ﬁle for test purposes. The audio ﬁle is named alarmsound.wav and is located in the the Data Directory (which can be identiﬁed from the main page View Directories). Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 44: Log Continuously Alarm For Darkness
Figure 7.31: Log Continuously Annotation tab Persistent annotation The “Persistent” mode makes the annotated text persistently appear at the end of each logged record after the ﬁrst time the hotkey is pressed. Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 45: 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 - 20211013...
Page 46 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 - 20211013...
Page 47: 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 - 20211013...
Page 48: 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 - 20211013...
Page 49: 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-V.
Page 50: 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-V. 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 51: 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 52: Data Logging Tab
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 53: Real Time Clock Setting Dialog
Figure 7.43: Real Time Clock setting dialog Pressing the “Set” button will copy the UTC time in to the SQM-LU-DL-V. Due to single second resolution, the clocks may never match within 0 seconds diﬀerence. The SQM-LU-DL-V clock is as accurate as a common digital watch, it may drift a few seconds per day.
Page 54: Dl Retrieve Dialog Window
See page 32 for more information. 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 55: 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-V. The data log window will be instantly updated with the result of your action and point to the latest record.
Page 56: 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 7.48. Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 57: 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-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 58: 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-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 59: 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 60: 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-V Operator’s Manual -...
Page 61: 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 62: 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 - 20211013...
Page 63: 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 64: 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 - 20211013...
Page 65: 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-V Operator’s Manual - 20211013...
Page 66: 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 67: 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 68: 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 - 20211013...
Page 69: 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 - 20211013...
Page 70: 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 - 20211013...
Page 71: 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 72: 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 73: 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 - 20211013...
Page 74: 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 - 20211013...
Page 75 ,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 - 20211013...
Page 76: Retrieve All Binary
8 Commands and responses 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 77 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 - 20211013...
Page 78: 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 79: Logging Interval Setting Response
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 63-64 Carriage return (0x0d), Line feed (0x0a). An example response is: Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 80: Logging Interval Reporting Period Setting
Conﬁrmation of setting command. Conﬁrmation of getting command. 3-21 Date, Day of week (1=Sunday), and time. 11-01-06 5 11:51:00 22-23 Carriage return (0x0d), Line feed (0x0a). An example response is: Lc,11-01-06 5 11:51:00 0123456789 123456789 123 Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 81: Get Real Time Clock Version
An example response is: La,000,128,128,128,001 0123456789 123456789 123 8.5.17 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. Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 82: Response Of Setting Or Getting The Mutual Access Mode
Table 8.36: Response of setting or getting the mutual access mode Column Example value Description Status mutual access. 0 = battery only logging is allowed. 1= PC and battery logging is allowed. Carriage return (0x0d), Line feed (0x0a). An example response is: LD,1 012345 Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 83: Vector Commands
8.6 Vector commands 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. All of the SQM-LU-DL-V datalogging commands begin with “v” (lower case).
Page 84: Acceleration Calibration Values
8 Commands and responses 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 85: 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 86: 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. Carriage return (0x0d), Line feed (0x0a). Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 87 8.7 Continuous reporting commands An example response is: YrCpu 01234 Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 88: Setting Interval Reporting Parameters
8.8 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 89: 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 - 20211013...
Page 90: 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 8.46: Table 8.46: Response of request for internal simulation values...
Page 91: 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 - 20211013...
Page 92: 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 93: 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-V Operator’s Manual - 20211013...
Page 94: 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 95: Firmware Upgrade
11 Firmware upgrade See the UDM “Firmware tab” section on page 50 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 96: 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 97: Altitude And Azimuth Calibration
12.5 Altitude and Azimuth calibration 12.5 Altitude and Azimuth calibration See section 8.6.3 on page 84 for details on calibrating the Altitude and Azimuth module. Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 98: 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 99: Usb Serial Number Garbled
• 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 100: 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 - 20211013...
Page 101: 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 102: 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 103: 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 104 14 Glossary Unihedron SQM-LU-DL-V Operator’s Manual - 20211013...
Page 105: 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¨...