Are Digi-Pas® Digital Levels calibrated/tested/certified by accredited international laboratories?
Yes. Digi-Pas® Precision Digital Levels have been calibrated and tested by accredited 3rd party independent bodies in the USA, UK, Germany and Japan traceable to NIST, JIS, UKAS & DIN standards.
To view sample of calibration certificate please click here
Are individual Digi-Pas® Digital Levels calibrated beforehand?
Yes. All the Digi-Pas® Precision Digital Levels have already been calibrated in our factories before they are sent out. You can actually use the Digital Levels right away, but we highly recommend that you perform a self-calibration before using to ensure its maximum accuracy.
Why do I need to perform "SELF CALIBRATION"?
It is recommended for users to calibrate their measuring tools and instruments periodically to ensure maximum accuracy conformance. Sometimes, improper handling, transporting, storing (e.g. out of specified storage temperature range) and accidental exposure to physical shock (e.g. dropping or hitting the device against some hard objects) may affect the accuracy of the device.
Digi-Pas® digital levels has a smart built-in feature which enable users to perform self-calibration with ease to set their digital levels back to its factory accuracy. Users can refer to their instruction manual for instructions on self-calibration, or simply watch our videos and follow the steps on how to How To Calibrate.
How do I know when I suppose to calibrate my Digi-Pas® digital level?
Whenever you have doubt over your digital level’s accuracy, or when you have unintentionally dropped or overheated (overexposure to heat with extended time period) the device. You can perform a quick check on your digital level by placing it on a clean flat surface and read the displayed reading in two directions (0° and 180°), ensuring that the device is placed in the exact location.
The device does not require a calibration in two situations:
The two readings in different directions are the same. (E.g. 0° and 0°)
The two readings are different, BUT within the tolerance of the device (E.g. either 0.05° or 0.1° depending on the model)
The device requires a calibration if:
The difference of the two readings are greater than the device’s resolution or completely out of range.
You may re-calibrate the digital level by following the videos in this link or instructions in your user manual.
How do I calibrate my Digi-Pas® digital level?
For horizontal calibration (steps 1 & 2), the surface onto which user place the digital level must not deviate from the horizontal level by more than 1° for optimum calibration result. Whereas for vertical calibration (steps 3 & 4), user must place Digi-Pas® digital level on true vertical surface to achieve an optimum calibration result.
Alternatively, user may contact respective Manufacture's Representative/Distributor to assist competent calibration at designated accredited 3rd party independent calibration service providers nearby user's geographical region.
What happens if I accidentally dropped my digital level or stored it outside the specified temperature range?
Likewise to any measuring tools or instruments, accidentally dropping your digital level or storing outside its specified temperature range affects the accuracy of your device. There may potentially be structural deformation that results from the mechanical shock on impact when dropped or thermal expansions and contractions when stored at an inappropriate temperature.
However, unlike traditional ‘bubble’ spirit levels and most digital levels available in the market, all Digi-Pas® digital levels are built with user’s Self-Calibration feature. This feature allows users to perform their own calibration without having to send it to laboratories for minor calibrations, incurring a cost and time as a result. Conveniently, users may simply reset the Digi-Pas® digital level back to its factory accuracy whenever there is a doubt over the measuring tool’s accuracy.
Why do I get two different readings when I take a reading facing one way, and then take another reading on reversed facing?
This situation may happen if the digital level is placed on a rough, dirty or uneven surface. Digital levels are highly sensitive to uneven surfaces and the angle measured on these surfaces will be inaccurate. Ensure that the contact surfaces are smooth and clean in order to achieve consistent readings. For example, to check your digital level’s accuracy (0.1° or 0.05° depending on model), a clean glass surface table finish is generally required.
Your digital level may have been subjected to extreme physical or temperature shocks during usage, transportation and even storage that may have affected its accuracy. All Digi-Pas® digital levels are built in with a Smart feature which empowers the user to perform Self-Calibration at ease. For more information on how to calibrate, see video links on How To Calibrate.
What is the accuracy of the digital reading versus the spirit Vial or "bubble"?
The accuracy of Digi-Pas® digital level is independent and higher than the built-in spirit Vial/Bubble. For example, the accuracy DWL-280 model is at ±0.05° (refer to calibration certificate webpage), but the built-in Vial "bubble" ° accuracy is only ±0.5° although the "bubble" seems rather sensitive.
Why do you still have a built-in spirit vial or ‘bubble’ in your digital levels? Are the accuracy the same?
Having built-in spirit vials or ‘bubble’ in our digital levels helps conventional users to relate to those traditional spirit levels that they are familiar with. In fact, the accuracy of Digi-Pas® digital level surpasses greatly to the built-in spirit vial and is independent of the spirit vial’s accuracy. While the spirit vials only have an accuracy of ±0.5°, advanced MEMS technology Digi-Pas® digital level’s accuracy is at 0.05° or 0.1° depending on the model.
What is the accuracy of Digi-Pas® digital levels?
Depending on the model, the Digi-Pas® digital levels have an accuracy of ±0.05° or 0.1° at 0° & 90°; and ±0.2 or ±0.3° at other °. Meanwhile, the spirit bubble vials have only an accuracy of ±0.5°.
For For more information on how we ensure the accuracy of Digi-pas®digital levels, click here
Why do I get different readings on the digital display when I turn my level around?
For Digi-Pas® digital level models having a resolution of 0.05° (e.g. models such as DWL-80Pro, DWL-180, DWL-280 and DWL-600F), the tolerance of these digital levels at 0 and 90° is ±0.05°. If the digital level is initially placed on the table and it reads 0.00° and thereafter when the digital level is turned 180° and placed at the same place, it should read 0.00 or 0.05°. If it displays neither those readings, recalibrate the level.
For Digi-Pas® models having a resolution of 0.1° (e.g., DWL-80E and DWL-200), the tolerance of these digital levels at 0 and 90° is ±0.1°. If the digital level is initially placed on the table and it reads 0.0° and thereafter when the digital level is turned 180° and placed at the same place, it should read 0.0° or 0.1° or -0.1°. If it displays neither those readings, recalibrate the level.
Why does the display reading 'flicker' during measuring?
If the display reading ‘flickers’ or show no readings at all during measurements, it could mean that the digital level has not been used correctly. Users is required to ensure that their Digi-Pas® digital levels are placed on its designated base firmly (i.e. without rocking) on the surface to be measured./p>
Click on the following link to see a video on how the Digi-Pas® digital levels are properly used, click here
Why do we need the 'Alternate Zero' feature?
The Alternate Zero function allows user to pick an angle and designate it as an "alternative zero angle point". This feature helps user to skip having to do the math for finding angles relative to a referenced angle set as 0°.
For example, the user has a table surface set at 5.0° and user would want to measure an object relative to the table. A Digi-Pas® digital level could be placed on the table surface and pushed the "alt zero" button. Thereafter, user could measure the object placed on the same table surface (same direction) and if reading shows 10.0°. This means that relative to the table surface, the object's angle measured is 10.0°. However, relative to the 'floor' where the table stands, the measured angle is 15.0°.
How do I get a new Digi-Pas® digital level instruction manual?
To download a copy of the instruction manual please click here.
What is the warranty period for Digi-Pas® digital level?
All Digi-Pas® digital levels are warrantied for a period of one (1) year from the date of purchase. The warranty covers defects in workmanship or materials at no charge. The manufacturer reserves the right to repair to its working condition or replace a new device at its discretion.
However, the one (1) year warranty clause is NOT applicable to the European Union (EU) member states. Purchases made in EU member states are covered by the existing consumer laws across the EU countries, which provide statutory warranty rights in addition to the one (1) year warranty coverage.
Are the Digi-Pas® digital levels waterproof?
Not all Digi-Pas® digital levels are waterproof. Waterproof models are DWL280Pro and DWL680Pro. In addition to being waterproof, these models are also shock-, dust- and freeze-proofs. For the remaining models (DWL80 Series, DWL100 Series, DWL200 Series, DWL600F and DWL1000XY), they are only dust-resistant. Any water damage voids the warranty coverage.
What are the special handling guidelines which need to be adhered for the waterproof digital levels (DWL280Pro and DWL680Pro)?
DWL280Pro Waterproof Digital Level has been tested and approved for IP67. User is required to ensure that the battery cap is completely tightened after inserting batteries into the battery compartment. The battery cap is completely tightened when the O-ring is compressed into the space between the cap and compartment to prevent water enter the compartment.
For DWL680Pro, users must make sure that the battery compartment’s tab lock is locked properly. The lock is secured when you hear a soft click.
Failure to do so will cause water to seep into the battery and electronic compartment, damaging the entire device and potentially voiding the warranty. For detailed information, please refer to the instruction manual
Can I use the Digi-Pas® digital level working on top of hot surfaces?
No, not all models have a wide operating temperature range. Most models have an operating temperature ranging between 0°C ~ +50°C and may not be suitable for extreme temperature working environment. Continuously putting the digital levels on the hot surface may potentially deform the plastic casing and damage the electronic unit, thus voiding the warranty.
For DWL280Pro and DWL680Pro, both models have a wider operating temperature ranging between -20°C ~ +60°C (-4°F ~ +140°F). These models can operate at hot working environment as well as in freezing weathers.
How do I switch the buzzer On or OFF?
Note: The DWL80 Series have no buzzer feature.
The buzzer sound can be turned on or off by simply pressing the ‘Alternate Zero’ button for more than 3 seconds while observing the buzzer sign on/off on the display screen. The buzzer is turned ON when the buzzer sign appears on the display screen. If there is no buzzer sign displayed, it means that the buzzer is OFF.
The DWL600 series has a different way to turning ON/OFF its buzzer. Please refer to the instruction manual for more details.
Can the volume of the buzzer be increased or decreased?
No, the buzzer has a standardized volume for all Digi-Pas® digital levels.
Why does the Auto-OFF feature seem to turn off the display after more than 3 minutes?
All Digi-Pas® digital levels are designed with intelligent software based on advance Embedded Technology. The sensor automatically detects a situation whereby the digital level is not used for approximately 3 consecutive minutes and automatically cut off its power to preserve battery life. However, if the digital level is still in use (i.e. sensing some movements), the display screen continue to display up to a maximum of 10 minutes before power is cut off.
What are the advantages of 2-Axis Digital Machinist Level over Single-axis digital/Bubble levels?
Traditional spirit level, pendulum-based digital level and inclinometer were constrained with (i) single axis, (ii) narrow angle measurement range, (iii) large footprint/size and (iv) inability to withstand high shock/impact applications. Single-axis inclinometer is also susceptible to cross-axis error particularly when measuring at larger angles and higher precision. However, precision levelling, angle measurement, alignment and surface flatness profiling tasks essentially involve 2-dimensional plane rather than two independent orthogonal single-axis lines. Digi-Pas® 2-Axis precision inclinometer utilizing advanced MEMS technology provides simultaneous 2-axis and wide angle measuring range capabilities that traditional bubble vials levels and single-axis pendulum-based inclinometers are unable to offer.
Utilizing Digi-Pas® 2-axis inclinometer translates into speedy machine installation and productive maintenance works with professional quality that maximizes precision machine performance. Thus, leads to improved user’s product quality (e.g. accuracy & yield) and higher customer satisfaction.
Digi-Pas® 2-axis digital inclinometer provides a comprehensive solution for precision levelling and angular measurement, and serves as a superior alternative that seeks to replace the use of outdated spirit levels and limited angle-measuring range of conventional single-axis inclinometers.
Is Digi-Pas® Digital Level calibrated/tested/certified by accredited international laboratories?
Yes. Digi-Pas® Precision Digital Levels have been calibrated and tested by accredited 3rd party independent bodies in the USA, UK, Germany and Japan traceable to NIST, JIS, UKAS & DIN standards.
To view sample of calibration certificate please click here
Why do I need to perform “SELF CALIBRATION”?
Precision measuring instruments commonly require periodic calibration to ensure accuracy conformance. Improper handling, transporting and storage, such as dropping subject the instrument to physical shock on impact or keeping them outside the specified storage temperature range are factors may affect accuracy.
Digi-Pas® precision digital level has a smart built-in feature that empowers user to do self-calibration with ease to set your precision digital level back to its factory accuracy. Take note that appropriate setup procedure and calibration equipment are needed. See video links on how to perform “User-Self calibration”.
Why do I get two different readings when I take a reading facing one way, and then take another reading on reversed facing?
This situation may happen when the precision level is placed on a rough, dirty or uneven surface. Precision digital level is very sensitive to sense any surface unevenness where placed. Ensure the machine contact surfaces are clean and smooth to get consistent readings. E.g. to check/verify your precision level of 0.01°, a typical machined surface is generally adequate. However, for precision level of 0.001° accuracy, a grade AA Granite Table (or an equivalent surface flatness of ≤3µm) is required.
Your precision digital level may have subjected to extreme physical or temperature shocks during usage, transportation or storage that affected its accuracy. An offset value of reading may have been present. Digi-Pas® precision digital level has a smart built-in feature empowers user to perform self-calibration to completely remove any residue offset and set to its factory accuracy. See video links on how to perform “User-Self calibration”.
Alternatively, User may choose an easy ‘quick solution’ to simply perform as Absolute Level Setting on the surface of the object to be measured to remove any residual offset on each measurement to be taken. Hence, accurate levelling readings can be obtained. In this case, no calibration equipment is needed. See video links on how to perform "Absolute Level Setting".
Can a user perform self-calibration for 2-axis precision levelling devices and what calibration equipment is needed?
Yes. User could self-calibrate for Digi-Pas® 2-axis precision levelling devices. However, appropriate setup procedure, Granite table and Master Square setup precautions are required. See video links on how to perform “User-Self calibration”.
Alternatively, user may contact respective Distributor/Manufacture's Representative to assist competent calibration of the device in those designated independent 3rd party calibration service providers nearby user's geographical region.
Is there any Calibration Certificate or Declaration of Conformity included in the instrument/device sold?
Yes. Each device/instrument sold and delivered is accompanied with a manufacturer's Calibration Certificate and a Declaration of Conformity Certificate for that specific device/instrument tested in Digi-Pas Laboratory according to ISO9001 standard. The Calibration Certificate and Declaration of Conformity ensure each device/instrument has been rigorously tested and strictly in conformance to stated specification traceable to NIST, JIS, UKAS & DIN through the National Metrology Center (a member of CIPM-MRA international standard).
To view samples of Digi-Pas° Calibration Certificate and Declaration of Conformity Certificate please click here
Alternatively, you may request to include a quote from our distributor to have the instrument calibrated & tested by competent 3rd party independent lab proximity to your geographical location.
What is the use of the 'Absolute Level' feature?
Absolute level feature is a useful mean of ensuring each measurement reading is in accordance to maximum device accuracy specified regardless whether the device has a measurement offset resulting from user's minor mishandling on device.
For more information on accuracy please click here.
Is it necessary to perform "Absolute Level" every time I measure an angle?
Yes. By performing "Absolute Level", you can ensure that the device is in accordance to maximum device accuracy specified by the manufacturer.
Note : The Absolute setting is reset once device is powered off
What is the use of Vibrometer and how it helps in precision levelling?
It is well-known that Vibration caused by improper levelling (machine footings uneven weight load distribution - result in machine 'rocking'!) affects high precision equipment/machine accuracy performance. Typical applications found in Continuous vibration magnitude recording/monitoring among multiple machines relative vibration on precision CNC machines can improve production yield and reduce scraps. Very useful in Coordinate Measuring Machines (CMM), SEM, MRI to achieve high quality 'sharp' images thus ensuring optimum measurement accuracy.
Digi-Pas® High Precision Dual Axis Digital Level with built-in Vibrometer (sampled at ≤10mS) allows user to record vibration patterns on precision equipment/instrument/machines and also their surrounding floor vibration and topographic changes over an extended period of time (i.e user defined) to identify vibration magnitude/pattern and analysis for achieving high quality machine levelling, alignment during setup and preventive maintenance.
Can I mount the 2-axis precision levelling devices on my machinery or equipment?
Yes. The mounting base of Digi-Pas® 2-axis precision levelling devices are provided with screw mounting holes. Users may refer to the Instruction Manual for further details. Please click here.
Can Digi-Pas® 2-axis precision levelling devices save data without using the PC Sync software?
No. You need to use the Professional version PC Sync software to save data into PC as there is no internal built in memory space in the device.
What is the effective range for the Bluetooth wireless connectivity?
Industrial Class 1 Bluetooth is used in Digi-Pas® devices and it has an effective range of 30 meters. However, most Laptop PC or tablet is built with consumer’s grade Bluetooth hardware having shorter communication range. The effective communication range can be further extended beyond 30 meters when user’s Laptop PC or Mobile Tablet is adapted with similar Industrial class 1 Bluetooth hardware as well.
What happen to the accuracy if digital level drops?
Likewise to any high precision measurement instrument/tool, mishandling such as dropping a digital level to floor or storing it outside the specified temperature range could affect its accuracy. This is primarily due to structural deformation resulted from mechanical shock on impact when dropped and physical micro-dimensional changes resulted from thermal expansion or contractions when storage temperature exceed maximum specified range.
However, unlike traditional 'bubble' spirit levels and many other digital levels in the market, all Digi-Pas® digital level is built with User's Self-Calibration feature. This feature empowers users to perform their own calibration without the need to sending to 3rd party testing laboratory when minor mishandling the device. At user's convenient work site or field work, User's Self-Calibration can simply reset the Digi-Pas® digital level back to factory preset accuracy whenever he/she is in doubt with the accuracy of the digital level.
For more information on accuracy please click here.
What is the battery life for the 2-axis precision levelling devices?
4 pieces of AAA batteries would last for over 6 hours in continuous use (i.e. LCD continuously turned ON). The firmware has intelligent power management system to automatically dim the display (i.e. user defined) for preserving power and prolong battery life over 12 hours.
Unlimited extension of battery life of the instrument can simply be achieved through the use of USB external power source connected to the USB terminal of the instrument. Also, when in Sync with PC, the USB cable link automatically supplies power to the instrument without the need of using the battery.
What is the warranty period for Digi-Pas® 2-axis precision levelling devices?
The warranty period for these device is 2 (two) years from the date of purchase. Please refer to Digi-Pas® warranty agreement webpage for further details. Please click here.
Any accessories included when I purchase Digi-Pas® 2-axis precision levelling devices?
Yes. We will include a durable casing equipment box, USB cable (3 metre), 4 x AAA batteries, 3 x base screws and manufacturer's Calibration Certificate.
Why do I need to update my device firmware?
It is advised to check for upgrades periodically to ensure the device is equipped with latest features to benefit from new features to enhance performance.
What is the difference between Basic and Professional version of PC Sync software?
Basic PC Sync software allows users to perform simple remote measurement and data acquisition while Professional PC Sync (optional) allows user to fully utilize the device for additional data logging and remote monitoring capability such as customization of data acquisition and measured data/readings saving for user analysis.
What is the PC requirement of the PC Sync software for 2-axis precision levelling devices?
User's PC is recommended the followings items to be installed for using the software:
Microsoft framework 3.5 for 32bit Windows OS or
Microsoft framework 4.0 for 64bit Windows OS
Windows XP service pack 3 / Windows Vista / Windows 7
The following item are required:
At least 1 GB Ram
At least 100MB free disk space
Microsoft Excel 2007 and above
USB 2.0 Port
Bluetooth adapter (for Bluetooth connection)
After plugging the PC Sync security dongle into my PC, why "Dongle is not found…" shown?
To get your dongle driver properly installed and functioned in your PC, please download the Dongle Driver from the following link and manually installed it into your PC.
Alternatively, the dongle driver installation folder can be found from the PC Sync software CD.
When I was trying to connect Digi-Pas® 2-axis precision levelling devices to PC via Bluetooth, the connection is unable to be established (E.g. No supported Bluetooth stack is detected or passkey requested for Bluetooth pairing process). What should I do?
You are required to install the Generic Bluetooth Adapter into your PC. Please follow the following steps to install the Microsoft Generic Bluetooth Stack:
Uninstall the current Bluetooth driver: Enter the Control Panel → Device Manager → right click your current installed Bluetooth stack and choose "Uninstall".
Install the Microsoft Generic Bluetooth driver: Download the correct Windows Version (according to your Window OS) Microsoft Generic Bluetooth driver from this link http://bluetoothinstaller.com/, run the installation file and follow the instructions of the wizard.
Restart your computer, enter the Control Panel → Device Manager, check whether the Generic Bluetooth Adapter and Microsoft Bluetooth Enumerator are installed. Please click here to see an example of screenshot of PC with the Bluetooth driver installed.
After confirming the Bluetooth driver is installed correctly as shown in the screenshot, you can start the Bluetooth connection with the PC Sync software now.
Advantages of using Digi-Pas® 2-Axis precision digital inclinometer over conventional single-axis levelling instruments:
Traditional spirit level, pendulum-based digital level and inclinometer were constrained with (i) single axis, (ii) narrow angle measurement range and (iii) large footprint/size. Single-axis inclinometer is also susceptible to cross-axis error particularly when measuring at larger angles. However, precision levelling, angle measurement, alignment and surface flatness profiling tasks essentially involve 2-dimensional plane rather than two independent orthogonal single-axis lines. Digi-Pas® 2-Axis precision inclinometer utilizing advanced MEMS technology provides simultaneous 2-axis and wide angle measuring range capabilities that traditional single-axis digital/'bubble' levels are unable to offer.
2-axis MEMS technology enables simultaneous 2D (X-Y plane) leveling and angles measurement instrument (i.e. pitch & roll), completely eliminates tedious trial-and-error (i.e. going back-and-forth taking reading one-axis at a time) experienced when using single-axis levels to align precision machines/objects. No costly need for owning 2 units of single-axis digital levels to do the same task as one unit Digi-Pas® dual-axis. i.e. effective & time saving. The repetitive yet monotonous trial-and-error activity of using single-axis levels is also time-consuming, non-productive and promote boredom that often succumb engineers to resort for compromising works.
Digi-Pas® 2-axis MEMS driven inclinometers are compensated and calibrated for non-linearity and operating temperature variation utilizing proprietary advanced manufacturing patented processes. Angular accuracy and stability performance over a very wide measurement range are externally verified by accredited 3rd party independent certification bodies traceable to NIST, UKAS, DIN & JIS. i.e. accredited & reliable. Because of its 2-axis, wide angular measuring range and vibrometer functions, Digi-Pas® inclinometer is more than just a leveling tool. It is an instrument that provides a comprehensive solution for planar angular leveling, measuring, diagnostic and alignment needs.
Digital Bull's Eye with numerical/graphical data and a built-in VibroMeter enable machine installer to track/guide alignment in real-time and instantly verify positional stability of the levelled/aligned machine by comparing machine's status profiles before and after setting up. Dual axis smart Bull's eye also prevents parallax error that is prone to experience when viewing the 'bubble' of a traditional spirit level, i.e. accountability & quality works.
Wireless/USB connectivity to PC/mobile device enables engineers to perform 'one-man-operation' when conducting levelling and alignment tasks, i.e. speedy & cost saving.
Utilizing Digi-Pas® 2-axis inclinometer translates into speedy machine installation and productive maintenance works with professional quality that maximizes precision machine performance. Thus, leads to improved user's product quality (e.g. accuracy & yield) and higher customer satisfaction.
Digi-Pas® 2-axis digital inclinometer provides a comprehensive solution for precision levelling and angular measurement, and serves as a superior alternative that seeks to replace the use of outdated spirit levels and limited angle-measuring range of conventional single-axis digital levels.
Precision Digital Level Accuracy and Reliability - Digi-Pas® 2-Axis Technology
In any precision measuring instruments and metrology, accuracy and reliability are very important aspects to users. Readings from an inaccurate measuring instrument/tool would result in making a faulty decision and in many cases could have unintended consequences.
Digi-Pas® 2-axis digital leveling instruments are built with advanced MEMS Sensor Technology and precisely calibrated for non-linearity for its entire measurement range using high precision computer numerical controlled equipment with resolution of 0.0001° (< 1 arcsecond). The accuracy and repeatability conformance of these highly specialized calibration equipment are further tested and periodically verified with ultra-high precision angular rotary systems (<0.01 arcsecond), as well as laterally compared against measuring data from world-leading accredited test and certification bodies in Japan, USA, UK and Germany, traceable to NIST, JIS, UKAS & DIN. Series of Calibration Certificates obtained from these certification bodies are obvious evidences of our product conformance to specification. This has demonstrated Digi-Pas® capability and its leading-edge technology to develop and manufacture world-first dual-axis high precision angular measuring instruments.
The digital technology adopted has enabled Digi-Pas® angular measuring instruments to be compensated for wide operating temperature variation utilizing Digi-Pas® patented advanced calibration processes (US Pat. No. 9,459,121 B2). Programmable precision temperature and humidity chambers are also utilized to calibrate various Digi-Pas® product lines for a range of -20°C to +60°C. This has enabled these products to reliably withstand stringent operating environment in many harsh terrains ranging from building skyscrapers in the desert of Middle-East to the constructing of oil pipes, tunnels and bridges in the freezing cold countries such as Canada, the Nordic and Russia.
Characterizing Digi-Pas® 2-Axis High Precision Digital Level
It is well known that a typical characteristic of MEMS tilt sensor inherently contents nonlinearity within its angular measuring range at any fixed operating temperature as well as when temperature changes. These nonlinearities affect angular instrument accuracy becomes even more significant when dealing with ultra-precision angular measuring system. Digi-Pas® employs our proprietary calibration processes utilizing advanced calibration technologies to stabilize multiple variables contributed by material properties, components and electronic system. Hysteretic nonlinearity and cross-axis error have been controlled and managed to a level negligible or within product’s specification.
Calibration and Testing of 2-Axis Precision Digital Level and Inclinometer
Calibration and testing of precision angular measuring instrument become very challenging at higher precision, wider measuring range and multi-axis. Test equipment’s linearity compounding error within entire measuring range and testing processes such as Swash errors become major impediments for establishing a responsible budget on measuring system uncertainties of no less than 95% confidence level at a coverage factory of k=2.
Over the years, Digi-Pas® has relentlessly made continuous improvements and closely collaborated with global leading 3rd party accredited test laboratories in USA, Japan, UK & Germany and world-leading National Metrology Institutes under Bureau International des Poinds et Mesures (CIPM MRA) to successfully test and verify with rigor our products performances to specification traceable to NIST, JIS, UKAS & DIN for international conformity assessments. These collaboration and cooperation have benefited many of our users in USA, EU and Asia to conveniently sending their instruments for annual calibration and test at a nearby laboratory for shorter lead-time and lower cost as these labs are in a close proximity to their respective geographical location.
Digi-Pas® patent (US Pat. No. 9,459,121 B2) on methods and apparatus for calibrating ultra-precision 2-axis simultaneous angular instrument (of < 1.0 arcsec accuracy) utilizing nano-technology equipment addresses and resolves critical limitations and shortcomings inherent when using conventional single-axis rotary table or laser interferometer to calibrate and test dual-axis precision digital anglular measuring instrument by taking one axis at a time.
Utilizing the "Absolute Level Setting" to Set Reference Level Point to Earth Datum
In leveling applications, the primary aim is to align the surface plane of a physical object such as a machine, equipment or engineering structure to a reference leveling point, commonly known by tradesmen as ‘zero level’. This ‘reference level point’ is a planar position tangent to the center gravity of earth i.e. refers as Earth Datum. This ‘reference level point’ can then be transferred into a leveling instrument. Subsequently, this leveling instrument is used by industrial engineers to set a particular machine/object surface to a required leveling position. The process of transferring Earth Datum to a Digi-Pas® digital leveling instrument is referred as performing "Absolute Leveling Setting". By performing Absolute Level Setting on Digi-Pas® digital levels, it also effectively removes any offset resides in the instrument and thus resetting the instrument’s reference leveling point to coincide with earth datum.
Similarly, "User Self-Calibration" is another alternative process to transfer Earth Datum and automatically store the reference leveling point into a Digi-Pas® digital leveling instrument.
What happen to the accuracy of Digi-Pas® leveling instrument if it drops?
Likewise to any precision measurement instrument/tool, mishandling such as dropping a digital level to the floor or storing it outside the specified temperature range, could affect its accuracy. This is due to structural deformation resulted from mechanical shock on impact when dropped and physical micro-dimensional changes (e.g. non-linearity) resulted from thermal expansion or contractions when storage temperature exceeded maximum specified range.
However, unlike traditional ‘bubble’ spirit levels and many other digital levels in the market, all Digi-Pas® digital level is built with User’s Self-Calibration feature. This feature empowers users to perform their own calibration without the need to sending to 3rd party testing laboratory for inspection when minor mishandling the device. At user’s convenient work site or field work, User’s Self-Calibration can reliably reset the Digi-Pas® digital level back to factory preset accuracy whenever in doubt with the accuracy.
What is "level" and "tilt angle" in angular measurement?
Generally, angular measurement involves a degree system, in which a full circle is divided into 360 equal degrees, while each degree is further divided into minutes and seconds. Within 360° angular measurement, "level" is a distinctive angle at zero degree (0°) which also means the true horizontal plane (i.e. tangent to earth datum). A "tilt angle" can be defined as inclination or any angle range measured which is deviated from the true horizontal plane.
Figure 1 and Figure 2 below illustrate a single-axis tilt angle and dual-axis tilt angles which involve two dimensional angles (i.e. θx and θy) of a plane respectively.
What are the differences between "levelling instrument", "inclinometer" and "protractor"?
A levelling instrument is a device used in establishing a horizontal line of sight, aligning a surface ‘flat’ to horizontal plane or at right angles to a plumb. An inclinometer is an instrument for measuring angles of an elevation, a slope or tilt relative to the horizontal line or plane. For example, a typical traditional spirit level is often single-axis levelling instrument which is specifically built to indicate the angular state of zero degree at the true horizontal plane. Often, additional ‘spirit bubbles’ are included to further indicate plumb (90º) and 45º. Usually, it cannot be used to measure other inclination angles or angular deviations. In contrast, advanced MEMS sensor technology enables Digi-Pas® digital levels and dual axis inclinometers to equip with the capability to perform (i) levelling function, (ii) single-axis and simultaneous 2-axis inclination/angle measurements of a plane and also (iii) most protractor function in conjunction with Alternate Zero feature.
A protractor is used for measuring the angle between two surfaces of an arc, i.e. a portion of a circle within a full rotation of 360°. This angle measurement is performed without referring to horizontal reference or earth datum which “levelling instrument” and “inclinometer” do. Hence, a protractor usually unable to indicate the state of level. The common types of protractors include manual half-disc protractor, bevel protractor and digital protractor. A digital protractor consists of a movable arm and a display screen which indicates the angle between its two arms.
Three-Point Contact Base of Digi-Pas® 2-axis Precision Inclinometer
Limitations of conventional rectangular contact base levelling instrument
The contact base surface finish quality of a typical conventional leveling instrument or inclinometer is one of the critical determinants of accuracy performance and common rectangular-shape flat surface often suffer from geometrical deviation resulting from:
Waviness and unevenness
Irregularities due to distorted or worn surface
Dust and dirt trapped or surface roughness
Figure 1 illustrates three typical poor surface finishes of conventional rectangular surface four-point contact base. The unstable surface-to-surface contact causes 'rocking' which results in measurement inaccuracy derived from inconsistent readings. A common practice to improve the outcome under such constraint is by taking more samples to obtain an averaged reading. However, this time-consuming and repetitive activity often promotes boredom that succumb engineers to resort for compromising works, especially when the instrument is located at some distance.
Although high quality surface requires both flatness and smoothness, it is difficult and expensive to control in machining of metal alloy surface particularly when involving relatively large area. Increasing the flatness and smoothness of a few microns would usually increase exponentially on its manufacturing costs. This often results in a trade-off between the manufacturing costs of the instrument and thus compromises its accuracy performance.
In addition, the rectangular contact base surface of a conventional leveling instrument is also susceptible to target measuring surface unevenness, which is another factor affecting levelling and measurement accuracy. Figure 2 illustrates issues associated when a rectangular contact base of a traditional single-axis spirit level is placed on a typical machined surface having low frequency, long wavelength flatness variation. It is clearly shown that full and stable surface-to-surface contact could not be achieved between the instrument base and the measuring surface. The contact may cause rocking that results in measurement errors, hence affects the accuracy and reliability of the leveling outcome. E.g. a 3µm of surface unevenness along the length of a typical 20µm/m resolution spirit machinist level of 130mm would result in 0.001° error
Digi-Pas® concave contact base versus 'perfectly flat' contact base structures
Often, dents are easily generated on smooth metal base area of an instrument resulting from rough handling. A protruding dent formed at any location near the middle of a 'perfectly flat' metal base simply causes rocking which results in measurement error or inaccuracy. To minimize these errors, Digi-Pas® instrument metal surface base has been deliberately designed and machined to form a concave 4-points contact base specifically target to prevent rocking caused by small protruding dents or foreign particles formed at the center of device’s base. Figure 3 illustrates the inferiority of a 'perfectly flat' base of conventional instruments against the improved design of Digi-Pas® concaved 4-point base when small dents/particles exist at the center of device’s base. It is obvious that small dents or particles exist near the middle of the base shall not affect stability of Digi-Pas® instrument as it is supported by both ends having precisely machined stable contacts to the targeted measurement surface.
On the other hand, dents formed at the both ends of the instrument may not necessarily cause significant rocking. When dents happen at these both ends, an offset value/reading caused by these dents can be easily removed using Digi-Pas® calibration or Absolute Level feature (see “Accuracy Performance”). In contrast, a protruding dent formed at the middle of the device’s base destabilizes the device with severe rocking during measurement which cannot be resolved by using calibration or Absolute Level feature. This phenomenon does not only affect the instrument's initial offset value, it also affects the repeatability of measurement reading.
Thus, the contact surface approaching the base center of instrument is deliberately being designed with a concave profile to minimize the above issue, providing improved stability of measurement readings as well as enhances accuracy of the instrument.
Pioneering the application of 3-point contact base in 2-axis precision levelling instrument
In view of the constraints inherent in conventional contact base measuring instrument described in the foregoing, Digi-Pas® pioneered and patented the utility of 3-point contact base for its 2-axis precision angular and surface flatness measurement instruments. The triangular shape of 3-point contact base seeks to address the shortcomings associated with conventional rectangular contact base.
When a 3-point contact base leveling instrument is placed on either flat or uneven surface object (e.g. typically machined metal surface) as shown in figure 4 and 5 respectively, the three-point frame serves as a triangle-plane platform for supporting the weight and maintaining the stability of the instrument. It provides maximum stability and strength against downward forces and horizontal forces as well as movements about horizontal axes. With the sturdy three-point stand, a most stable 3-point-to-surface contact can be established without rocking and thus achieving consistent leveling readings of the two-dimensional measuring surface. Any angular deviations on the surface area is detected by Digi-Pas® 2-axis inclinometer as sensitive contact points touch on a particular section of uneven surface area.
Advantages of Digi-Pas® 3-point contact base levelling instrument
In 2009, Digi-Pas® pioneered and patented the utility of 3-points contact base to its world-first 2-axis precision digital level series that effectively prevent any surface dimensional deviation caused by unevenness of its own instrument’s metal surface contact base. Figure 5 illustrates the 3-point contact base screws made of harden steel and titanium materials that offers great stability and prevent it from ‘rocking’ when placed on either flat or uneven smooth surface for 2D levelling and planar angular measurement.
Maintaining the 3-points contact is easy, speedy and cost effective simply by replacing the harden/titanium screws whenever they wear off, saving significant amount of time and cost as compared to maintain the instrument’s contact base surface finish through standard machining. Device accuracy performance can also be re-calibrated by performing User Self-Calibration or “Absolute Level” setting at ease. Please refer to user manual for detail instructions.
For using Digi-Pas® 2-axis inclinometer to level an object having a very rough top surface, the 3-point harden/titanium screws can be temporarily removed and use the flat base surface to naturally average the rough surface. Absolute Level Setting is required to be performed immediately after changing the base to ensure the instrument maintains its reference accuracy. However, in high precision leveling, angular measurement and surface profiling tasks usually involve high quality flatness and smooth surfaces such as granite and metal alloy machined surfaces. Hence, 3-point contact base is still a better choice.