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Vaisala FAQ Frequently Asked Questions concerning Vaisala

Vaisala FAQ Frequently Asked Questions concerning Vaisala

Vaisala - Frequently Asked Questions

 



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Data logger accuracy - 0.10°C / 1%RH or 0.15°C / 2%RH ?

Your Vaisala documentation occasionally lists accuracy figures of ±0.10°C for temperature and ±1% for RH, but also ±0.15°C and ±2%RH. What is correct ?
Actually, both figures are correct. Vaisala data loggers are designed and calibrated to be accurate to within 0.10°C / 1% RH (relative Humidity,) placing them amongst the most accurate battery operated data loggers in the world.
Temperature and above all humidity sensors, however, can change with age, so it is important for the user to know what accuracy the unit will maintain after one year's use, the typical annual recalibration period. Vaisala guarantees an accuracy of 0.15°C / 2% RH (!) after one year when properly used.

What is PoE ?

PoE is the acronym for Power over Ethernet and describes a system to transfer electrical power, along with data, to remote devices over standard twisted-pair cable in an Ethernet network without the requirement for mains power. Power is fed into the net at any point, often at the server side to make use of the server's backup power.
This doesn't immediately concern Vaisala data loggers due to their internal 10-year life battery. Still, connecting the data loggers to the IT infrastructure via an Ethernet device offers two advantages: Firstly, no local mains power is required and secondly, PoE can easily be maintained via the emergency backup supply.

Do Vaisala calibration certificates conform to DKD requirements ?

Yes ! Vaisala data loggers are calibrated in Vaisalas own A2LA accredited DIN EN ISO/IEC 17025 laboratory, traceable to international standards. A2LA is the North American equivalent to the German DKD, the Suisse SAS or the Austrian BMwA, all of whom recognize each others accreditations.

How come Vaisala data loggers never show any battery problems?

Many loggers available in today's market suffer battery problems resulting from two main causes: battery life and battery contact issues.
Each case can result in data loss or incomplete recordings should the logger cease to function correctly in the middle of an important validation run. Reliable predictions about when this might happen are next to impossible, as most batteries can hold their voltage near 100% for almost all their life, only to drop suddenly near the end.
The electronics of the Vaisala data loggers are optimised right down to the last detail, so they can operate with minimal power consumption. This results in a 10-year battery life, offering safety and reliability for many years to come. As a positive side effect of the extremely long life battery contacts can be soldered to the electronics, making all contact problems resulting from oxidization or shock a thing of the past.

How do the FDA CFR 21 Part 11 requirements relate to the VL Data Logger system?

The CFR 21 Part 11 regulations apply to any electronic records that are used as a part of GMP documentation, including the ones produced by the Vaisala VL-series data logging system.
The following table summarizes the key requirements of the CFR 21 Part 11 regulations and how the VL-series system addresses those requirements.
For further details please find the White Paper on Vaisala 21 CFR Part 11 Compliance.

How does the Continuous Monitoring System and VL data loggers produce GMP-compliant records?

The VL-series data logging system is a set of monitoring tools that have been designed for use within the framework of a company's GMP-compliant record-keeping and documentation system. The system produces paper-based data logging records that, after signed review and approval by responsible parties, can be used in a GMP-compliant documentation package. As a part of this process, the VL-series system creates and uses secure and unalterable electronic records consistent with GMP requirements for authenticity and accuracy.

How long can Vaisala data loggers record for?

The length of time Vaisala data loggers can record for is determined by the number of input channels enabled on the logger, the recording frequency (sampling interval), and the size of the memory (32K or optional 105K).
Vaisala data loggers can, for example, record data continuously for 10 years (at a typical sampling rate of once per minute) without any need for a battery replacement. For a typical two-channel data logger that's over 10 million non-stop readings.
For a general guide, refer to the specifications page for the specific data logger model you are interested in.

How do I stop communication alarms?

  1. Ensure your loggers are plugged in.
  2. Ensure your Digi is connected to a power supply and the power supply is plugged in. The light on the front of the Digi should be solid red.
  3. Ensure the Digi is connected to and communicating with the network. Try to ping the Digi by typing the following at a command prompt: ping .
  4. If there is communication between the Digi and the network, check that the Verieq-supplied cable connecting the logger to the Digi is functioning properly. When the cable is functioning properly, the light should be mostly off with an occasional flicker. If the light on the cable is solid red, there is a problem with the logger cable or logger. See step 6.
  5. If the light on the cable is working correctly but you are still getting communication alarms, go into Device Manager on the viewLinc Host computer and ensure the Digi is still installed. Under the Ports category in Device Manager, you should see an entry for Digi SP One. If you don’t see this, reinstall the Digi by following steps 2 B and C from the Quick Start Guide for viewLinc with Digi Devices.
  6. If the light on the cable is not working properly, open a graphing application (vLog or Spectrum) and determine if the logger can communicate with the graphing application. If there is a problem with the logger communicating with the graphing application, it is likely the logger or logger cable is not functioning properly. Try connecting a new logger – or a logger that is known to be working – and see if you can connect to it in vLog or Spectrum.

Which COM ports is my Digi device using?

There are two easy ways you can check to see which COM ports are associated with which Digi Device. Both include accessing the Device Manager in Windows.

Open Device Manager (From Start, choose Settings, Control Panel, Administrative Tools, Computer Management. Device Manager is on the left hand side).

Once Device Manager is open, click on Ports (COM & LPT) to see which COM ports are connected to which devices. (The Digi Devices should be named Digi xxxxx (where X is the model of the Digi).

The next option (for more detail), is to go to Device Manager (Start, Settings, Control Panel, Administrative Tools, Computer Management, Device Manager is located on the left hand side), and, under Multiport serial adapters, right-click the device in question. Choose Properties, select the Advanced tab, click on the properties button. On the left will be a list of the COM ports used for this device.

What if I cannot communicate with the logger(s) connected to my Digi device?

If you cannot communicate with loggers attached to a Digi device using Vaisala software, there may be a problem with the way the Digi is configured.

Please check the folowing, retesting communication after each step:

  • The Digi device is plugged in to your network and powered on;
  • A logger is attached to the Digi device;
  • The RealPort driver has been installed. There should be a listing for a Multiport Serial Adaptor with the IP address of your device in Device Manager. There should be a listing for one or more Digi RealPorts under the Ports (COM & LPT) heading in Device Manager. If the driver has not been installed, perform step 5 on the Digi Setup Page (see instructions for viewLinc)

Make sure the Vaisala software is configured to communicate with the correct COM port (see the Ports (COM & LPT) section in Device Manager). In Spectrum or vLog go to Tools>Options and select the correct COM port from the drop-down menu.

If things still don't work, reconfigure the Digi device using the instructions below:

  1. Enter the IP address of the device into a web browser
  2. Enter the username and password at the login screen (the defaults are root and dbps).
  3. Once you are logged in, click on the Setup Wizards link
  4. Click on the RealPort link
  5. Follow the wizard, enabling RealPort and NOT enabling Altpin
  6. Click on the Admin link
  7. Click on the Reboot link and follow the wizard to reboot

If you still cannot communicate with the logger, it may be due to a problem with the RealPort driver installation. During the installation there is a step that asks you to enter the number of serial ports. This refers to the number of physical ports on the Digi device, not the COM port number that you want to allocate to the device (eg. for a Digi One RealPort you would enter 1, for a Digi PortServer TS4 you would enter 4). If the incorrect number is entered here, it is quite likely that you will not be able to communicate with a logger attached to the device.

To fix this problem, uninstall the drivers by right-clicking the listing for Multiport Serial Adaptor in Device Manager and selecting Uninstall. One the uninstall is complete, reinstall the driver ensuring that you specify the correct number of ports.

What if the Digi Setup Wizard cannot save settings to the Digi device?

When going through the Digi Setup Wizard, if the you get a message stating that it cannot save the settings to the device even though the device is visible in the discovery portion of setup (and also responds to a ping), then it might be a problem with proxy settings on the your internet connection. This might also prevent you from logging in to the device's web interface.

One way to check if you connect to the Internet through a proxy server:

  1. In Internet Explorer, go to Tools>Internet Oprtions
  2. Click on the Connections tab
  3. Click on the LAN Settings button
  4. See if there is a check mark in Proxy Server box

If you are using a Proxy Server, you may have to add exceptions for the IPs that the Digi devices are using. Here's how to do that:

  1. Click on the Advanced button in the Proxy Server section of the window opened above
  2. Enter the IP addresses of the Digi devices in the Exceptions box
  3. Click OK on all of the windows until you get back to the browser

Once this is done, try to log into the Digi's web configuration utility (by entering the IP address into a browser). If you are able to log in (the default username / password is root / dbps), then configuration can be done through this interface as below:

  1. Click on the Setup Wizards link
  2. Click on the RealPort link
  3. Follow the wizard, enabling RealPort and NOT enabling Altpin
  4. Click on the Admin link
  5. Click on the Reboot link and follow the wizard to reboot

The Digi device is now configured. The RealPort driver has not been installed yet, so do not forget this step. To install the RealPort Driver, perform step 5 on the Digi Setup Page (see Vaisala CMS Installation Quick Start Guide). These steps must be repeated for each Digi device.

What if the Digi Setup Wizard does not see my Digi devices?

The Windows XP firewall will often block IP addresses that it does not recognize. When installing a Digi device, if the Setup Wizard fails to find a device that is known to be attached to the network, it is possible that the firewall of the local computer is blocking access to this IP address. To test if this is the problem, simply disable the firewall by following these steps:

  1. Right-click My Network Places and select Properties
  2. 2.Right-click Local Area Connection and select Properties
  3. 3.On the Advanced tab, click the Windows firewall button
  4. 4.Disable the firewall and click OK

Once the firewall has been disabled, try to run the Setup Wizard again. If it discovers your device then the XP firewall was the problem. Complete the rest of the wizard to finish installing your device. The firewall can be re-enabled after the Digi device has been installed.

My changes to thresholds and logger descriptions aren't showing up - why?

Channel information is updated and refreshed depending on the refresh rate set in viewLinc. Determine the refresh rate viewLinc is using and wait the allotted time.

What if I am having problems trying to transfer Vaisala data logger files to a network location?

You need to ensure that the account that's running viewLinc has write permissions to the folder where you're attempting to transfer the logger files. The account that’s running viewLinc was set during installation. See information on installing viewLinc in the Administrator guide or online help.

How does viewLinc know which Digi devices (with attached loggers) are assigned to it?

It doesn't. Digi devices aren't 'assigned' to viewLinc; rather, viewLinc monitors the network for loggers attached to COM ports. As mentioned, viewLinc software communicates via COM ports. Installing a Digi device using the Quick Start Guide creates virtual COM ports which are monitored by viewLinc.

To see which COM ports are assigned to specific Digi devices, use Device Manager:

Open Device Manager (From Start, choose Settings, Control Panel, Administrative Tools, Computer Management. Device Manager is on the left hand side).

Once Device Manager is open, click on Ports (COM & LPT) to see which COM ports are connected to which devices. (The Digi Devices should be named Digi xxxxx (where X is the model of the Digi).

For more detail, in Device Manager, under Multiport serial adapters, right-click the device in question. Choose Properties, select the Advanced tab, and click on the properties button. On the left will be a list of the COM ports used for this device.

To see which loggers are being controlled by viewLinc, see the System tab.

How do you add IP addresses for Vaisala data loggers?

You don't. But, you do assign IP addresses to Digi devices. Because viewLinc communicates using COM ports, attaching data loggers to the network using Ethernet/IP addresses requires the use of a Digi networking device.

Digi devices create virtual COM ports that allow data loggers to communicate with viewLinc using Ethernet. Digi devices should be configured with static IP addresses, which should be obtained from your IT department prior to installing the Digis and viewLinc. IP addresses are assigned to Digi devices during Digi driver installation.

Refer to the Vaisala viewLinc Quick Start Guide for Digi devices for installation instructions. For more about Digis, see www.digi.com.

How do I move my Digi from one location to another (same subnet)?

If you've used a static IP address for your Digi (as recommended) and are moving your Digi to from one location to another within the same subnet, here are the steps to follow:

  1. Shut down all Vaisala software, if desired. (You may experience communication alarms while performing these steps if you don’t shut down viewLinc).
    NOTE: You do NOT need to uninstall the Digi software from the viewLinc Server. In fact, doing so will potentially cause problems when you reattach the Digi to the network.
  2. Move the Digi to another location.
  3. Plug the Digi into the network again.
  4. Restart Vaisala software. viewLinc should be connecting to the Digi and see the loggers.

What type of humidity sensor is used on the Vaisala 2000 series loggers

The 2000-series loggers use a thin-film capacitance relative humidity sensor. The sensor is based on a thermoset capacitive polymer and, using a three-layer capacitance construction, consists of parallel plates with porous platinum electrodes, all mounted on a silicon substrate. The electrodes are coated with a dielectric polymer that absorbs, or desorbs, water vapor from the environment with changes in humidity. The resulting change in dielectric constant causes a variance in capacitance and impedance that relates to changes in relative humidity.

In operation, water vapor in the active capacitor's dielectric layer equilibrates with the surrounding gas. The porous platinum layer shields the dielectric response from external influences while the protective polymer over-layer provides mechanical protection for the platinum layer from contaminants such as dirt, dust and oils. A heavy accumulation of dirt or contamination on the sensor will not affect sensor operation except to slow down the sensor's response time.

We already have an automated humidity and temperature control system for our process that can also record data. Why then would I need to use a separate data logging system?

Properly validating a process requires objective evidence and a common practice in the industry to obtain this evidence is through redundancy. This means that if there is an automation system controlling a process and a logger monitoring the process, independent sensing systems must be used. For example, if one system is controlling the humidity in a room, a completely independent system should be recording it.

Control and recording systems that operate without redundancy can appear to work satisfactorily but may, in fact, be operating well outside of specifications. Redundancy provides an objective double-check of system performance and, additionally, makes it obvious if either the controller or the logger is out of calibration.

Do you provide any assistance to validate this data logger system for our facility?

Yes. A Validation Protocol Manual and CD for the Vaisala VL-series validation/mapping and data logger system is available. This time-saving package has been designed to help you quickly prove the effective functional performance of the system and to assist in validating the software for use within your facility. The package includes installation qualification (IQ) and operation qualification (OQ) procedures and forms to enable you to record all details needed to demonstrate that the system is working properly. This validation process provides assurance that the system has a high level of integrity and the data is accurate and reliable.

Secure data logger files: What are they and why are they important?

Secure data logger files are tamper-proof files created using vLog Software from a VL-series Validatable data logger. vLog Software can recognize whether a data logger file has been modified from its original state by referencing an authentication signature which it has embedded in each file. If the file has been modified or tampered with, it is rendered unusable by the program.

Secure files are essential when the data you are recording is very important or has a high liability attached to it. As an example, a pharmaceutical company may stand to lose a substantial amount of money if the storage conditions being recorded for a particular drug product are not within specifications. Since there is a possibility that an unscrupulous operator may attempt to alter the records to save his company money, a secure file provides confidence to all parties, including the regulatory agencies, that the record is authentic and a genuine representation of actual conditions.

What is meant by the terms "validation" and "validatable"?

Validation is the process of proving that something does what it is supposed to do. It is a very important process in the pharmaceutical industry that is falling under increasing regulation. The FDA's definition is establishing through documented evidence, a high degree of assurance that a specific process will consistently produce a product that meets its predetermined specifications and quality characteristics.

The term "validatable" means capable of being validated. Three issues are essential before equipment can be considered validatable:

  • There must be documented evidence of performance verification available. As an example of this requirement for documented evidence, a NIST-traceable calibration certificate is provided with every Vaisala VL-series data logger.
  • The equipment must match the specific requirements of the application. Each application may involve special accuracy, operating range, performance stability or other requirements that the product must meet.
  • The equipment must be capable of maintaining a validated state throughout the application process. The product or its output cannot be manipulated, changed or tampered with.

Why are Vaisala data loggers so small and what are we giving up going small?

The most striking advantage of small size is usability. Smaller units are easier to carry around, easier to ship, easier to deploy, easier to use and far less obtrusive to the process being monitored. Our customers constantly tell us that our compact units are used, quite simply, far more often than existing bulkier alternatives.

In most cases, you are giving up nothing by doing small. Our experience has told us that most of our customers purchase data recording instrumentation because of a need to record just one type of measurement variable. In response to this, Vaisala data loggers have been optimized around specific sensors or input signals that result in more compact and efficient designs, without compromising accuracy or performance.

In contrast, larger instruments typically have numerous bells and whistles designed to span a broad spectrum of possible functions and uses. This often results in overkill with an added penalty of size, cost and battery life. Larger instruments, for example, typically offer more input channels while Vaisala loggers employ a modular design. They also typically perform on-board processing in order to display real-time readings while Vaisala loggers efficiently off-load this process to a PC.

Should I turn the logger off to save battery power? What if the battery runs out?

Vaisala data loggers have a battery life of 10 years based on continuous operation at one minute sample rates. To maximize battery life when not in use, set the logger to an infrequent sample rate such as once per hour.

You can also prolong battery life by keeping the logger out of continuous operation at extreme operating temperatures, and downloading data to your PC at frequent intervals.

If the battery does run out, contact Vaisala for a factory battery replacement. For critical applications, we recommend replacing the battery 8 years after purchase.

Why do I want a 10-year battery? Isn't 1 year enough?

One of the main reasons for ten-year battery life is reliability. Long battery life virtually eliminates the chance of data loss due to dead batteries. In most applications, you'll send your data loggers in for calibration long before the battery dies; we check the batteries when calibrating the loggers.

The long life also minimizes the need for replacement batteries and allows the battery to be soldered in for maximum dependability of the battery connections. These considerations are especially important in critical applications where the data is vital for compliance and product efficacy.

While a conventional data logger or recorder may have a one-year battery life, this shorter life can be problematic because the actual life of the battery may only be six months (or less) once it leaves the factory. This uncertainty can lead users to make frequent battery changes in order to avoid the possibility of data loss — a time-consuming practice, especially when dealing with a large number of units.

Frequent battery changes require a user-replaceable battery design that can lead to further problems. User-replaceable batteries are susceptible to shock and vibration that can result in battery dislodgement. Also, battery holder contacts commonly oxidize, especially under varying moisture and thermal conditions, causing insulating deposits that interrupt or trigger intermittent battery operation.

How is the Vaisala data logger 10-year battery life achieved?

Vaisala data loggers have been optimized from the start for exceptionally long battery life. This is accomplished through a low-power design architecture, high efficiency operating routines, and a long-life lithium energy cell.

As an example, one of the biggest power consumers in any measuring instrument is the sensor circuitry. In a typical chart recorder this circuitry is powered continuously, a condition that can drain the battery rapidly. Vaisala data loggers only power this circuitry long enough to take a set of readings, typically for just a fraction of a second. After each set of readings, the circuitry is powered down (i.e. put into a "sleep mode") to conserve energy until the next reading.

Another example of energy efficient operation is in the computation of accurate measurement readings. Many of the sensing technologies used on Vaisala loggers (i.e. thermistors and thermocouples) involve the use of highly complex calculations that require intensive computational processing to achieve accurate results. The Vaisala system has been designed to offload this power-consuming process onto the PC for both maximum efficiency and accuracy.

What is "resolution" in terms of data loggers?

Resolution is the smallest change that can be distinguished by a measurement instrument. It is sometimes referred to as "sensitivity" or "precision" and is limited by the number of bits that the instrument uses to quantize the signal it is measuring. The greater the resolution of an instrument, the smaller the changes in the input signal that can be measured (or resolved). As an example, an 8-bit instrument can resolve to one part in 256 (2 to the power of 8), a 10-bit instrument can resolve to one part in 1024 (2 to the power of 10), and a 12-bit instrument can resolve to one part in 4,096 (2 to the power of 12). From this information, we know that a 12-bit logger has a resolution sixteen times better than an 8-bit Logger.

To understand this even better, here's an example of resolution (and how it affects measurement accuracy) using a tape measure analogy:

You have a 20-ft. tape measure. If the tape was labeled using 8-bit resolution, each marking on the tape would be about one inch apart - with no markings in between - just blank space. A "coarse" tape measure like this might be useful for building a treehouse or setting up a tent - but not much more.

If the tape was labeled using 10-bit resolution, the tape would have a marking every quarter of an inch, a significant improvement. Maybe we could use this one for the garden shed or the compost box at the back.

With 12-bit resolution, the tape measure will have markings every one-sixteenth of an inch, making it precise enough to build out that new addition to the family room.

What happens to data during logger downloading? Does logging stop, or does it carry on? Is the data cleared?

The logger keeps recording throughout the downloading process. When a logger is downloaded the software makes a copy of the data in the logger's on-board memory and creates a back-up file on the computer. No changes are made to the operation of the logger and the data within its memory is only cleared you do this via the software.

Can I rent a data logger system for a short term validation or mapping?

Yes. You can also test drive our solutions and have a percentage of the rental fee applied towards a purchase if you decide that Vaisala's system is a good fit for your needs.

 

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