DataTrace® - Frequently Asked Questions
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Tips for Reading Data Logger Data
Occasionally when downloading a DataTrace data logger, communication between the logger and the interface can be interrupted, which can have a number of different reasons.
Although this is rare, communication can be re-established by following a few easy steps, that will not affect data collection or storage.
If the logger you are downloading with the DataTrace (DT) Pro Software is not immediately communicating with the interface, try these steps in sequence until communication is restored:
- Rotate the logger in the interface and re-test; this will provide a different contact point on the case and may immediately re-establish communication.
- Close DT Pro Software, unplug the USB lead, re-attach the USB lead and retest. Sometimes the USB bus loses connectivity, and by re-plugging the lead the device connection is re-established.
- Try a different USB port on the computer. Similarly to step 2 a different port can provide subtly different behavior.
- Reboot the computer. This should only be required in extreme circumstances where a driver has become unresponsive.
If neither of these steps can establish communication, the logger’s battery may no longer have sufficient capacity to communicate with the PC. In this case we would recommend you open the battery compartment and replace the battery (also remember to replace the O-ring at the same time).
If communication still cannot be achieved after a battery replacement, it is best that a qualified technician establishes the cause of the problem. This can be arranged directly with CiK Solutions.
How can I estimate the battery life remaining in my Logger?
Battery life is extremely difficult to estimate and is not a precise value. Batteries have a very wide variation in life cycles from one battery to another of the same type. In our experience battery life in general is very much affected by three application-driven situations:
- How frequently the Logger is used
- The temperature extremes and the duration of those extremes to which the Logger is exposed
- The Sample Interval defined
In the years of experience that we have had with the Standard Temp battery (Micropack, Flatpack, and FRB Loggers), we have found that on average users receive between 9 months and 12 months of useful battery life. Obviously, this will vary, but appears to be a reasonable estimate. This corresponds reasonably well to our on-going testing in-house in our own sterilizer.
The Pressure Logger will consume, normally, twice as much power as the Temperature-only Logger, while the Humidity Logger is between these extremes.
The MPIII Logger uses a considerably smaller size battery which will have a much shorter life expectation. Based on initial process testing and our normal on-going testing, we expect the battery life for MPIII Loggers to be approximately 2 to 3 months with similar caveats as above. However, the MPIII Loggers have a battery life indicator that displays an estimated remaining battery life when the Logger is tested or programmed.
Will operating a Logger outside of its specified operating range have any negative effects on the Logger?
Operating a Logger outside its specified range may affect the Logger in several ways. It may stress the battery and/or electronic components resulting in changes in accuracy, stability, or complete failure. The impact obviously worsens the more outside the specified range to which the Logger is exposed. While some of these changes are reversed when the Logger is returned to the appropriate range, others may be permanent or irreparably damage the Logger.
Why did a Logger I sent for repair return with a different Serial Number?
MPIII Loggers will be returned with a different Serial Number if the MPIII probe is damaged or needs to be replaced. The design of the MPIII Logger includes the probe as part of the body assembly. The Serial Number is laser-etched onto the MPIII body before assembly. During service for probe damage, a new body (with a new Serial Number) must be used.
Can I use a mercury and glass thermometer to verify my Logger?
The best way to use a glass thermometer as an accurate measurement instrument is to:
- only do so in a well-stirred liquid medium
- only use it at its rated immersion depth
- do not use it at temperatures too far from ambient
Mercury and glass thermometers can be accurate if they are used in the situations and environments they were designed for. Many glass thermometers are rated as full immersion; this means that to achieve their rated accurately they must be fully immersed in the environment they are measuring, frequently this is air. These types of thermometers are appropriate for environmental measurements, not for use in liquid mediums.
There are glass thermometers that are calibrated and designed for measurements in liquid. However, it is even more critical that immersion depth be observed with these units. As suggested above all temperature measuring devices have a rated immersion depth, at which there will be no measurable stem effect from heat being conducted to or from the ambient environment along the stem to or from the tip. Failure to adhere to the immersion depth requirement will introduce significant inaccuracies into the measurement.
Finally, the further from ambient that the target temperature is, the more errors can creep into the measurement due to procedural or equipment related issues.
What type of battery do I need for my DataTrace equipment?
The batteries used in DataTrace equipment depend on the type of Loggers being considered. Except for the non-MPIII PC Interface, which uses a standard 9 volt battery, Logger batteries are not standard off-the-shelf designs. The battery chemistry is Lithium Thionyl Chloride (non-MPIII Loggers) or Carbon Monoflouride Lithium (MPIII Loggers) customized for use in DataTrace Loggers. These batteries are available from DataTrace along with the accessories necessary to accomplish a field battery replacement.
Can I write on, or put a sticker on my Logger?
Some customers have unique "tags" that they wish to place on their Loggers. In some cases these reflect mapping IDs used as visual cues for validation process locations and for others they define individual pieces of capital equipment.
DataTrace recommends that no stickers be placed on Loggers for several reasons.
- It is possible that the sticker placement could conflict with Logger communication.
- When a Logger is returned for service, the fixtures used on the Logger will damage or destroy the sticker during disassembly.
- The sticker and/or sticker adhesive could contaminate the silicone oil in the calibration bathes.
While writing on the case with an indelible ink can be helpful, it is limited. Consideration must also be given to any contamination to the process caused by the ink itself.
An alternative worth considering might be electro-chem etching. This would be safe, clean, and would add no conflict with communication or factory fixturing. This process has been used for years by DataTrace.
I just connected my MPIII PC Interface and it does not seem to work, what's wrong?
The MPIII PC interface gets power from the serial port of the PC. However, because the optical emitters use more power for very brief periods than the PC can supply, the Interface stores energy in very large capacitors built into its circuitry. These capacitors make a total of 2 Farads, much more energy storage than conventional capacitors. Unlike batteries, these capacitors can charge and discharge over and over without wearing out, so they should never need to be replaced. But like batteries, their charge rate must be limited, and as a result it takes a little time for them to rise to operating voltage. Normally, the PC Interface is fully charged before it leaves the factory.
The Interface is being charged when it is connected to the computer and the DTW program is active. Once they are charged from zero, they do not decay much over time and usage and can normally be used right away. However, their charge could decay slightly over time due to stray current leakage. For this reason, if the interface does not work when it is first plugged into the serial port, usually waiting about 2 minutes with DTW active will bring the Interface to full power and it will start working. Even if the capacitors are fully discharged, it only takes about 15 minutes before it will work properly.
A fully charged interface can be stored for several weeks before the charge decays enough that it will not work immediately when it is connected to a PC. However, this will vary from one unit to the next.
What is my Logger's clock accuracy and how is it checked at the factory?
The Logger does not have a clock, but uses a timing circuit, based on a highly accurate oscillator (approximately 30ppm). As with all oscillators, high temperature affects them. However, in the case of the oscillator used in your Logger, the actual impact is not significant. For example, in the worst case where a Logger was operating at 150 °C for 24 hours, the timing would be off less than 30 seconds.
Timekeeping accuracy is evaluated inherently as part of the calibration process for each Logger.
Initially, during the calibration procedure, the Logger is programmed on the computer which is used to operate the calibration bath and log the reference temperatures. Following programming, the Logger is immersed in the bath and the computer commands the bath to go to a certain temperature. When the bath software detects that the bath temperature is stable enough, measurements are taken with the reference thermometers. After the measurements are recorded, the bath is commanded to change to the next calibration temperature.
This procedure is repeated every 5 °C throughout the Logger's temperature measurement range. After the calibration data is acquired from the reference thermometers during the calibration process, the Logger is removed from the bath, cleaned and read.
The data that the computer acquired during calibration includes the temperature at each stable point, and the exact time these data points were taken. This reference data is then compared to the readings from the Logger, at each point in time. If the Logger timekeeping were not accurate, it could not pass the calibration or calibration accuracy verification. Even if the Logger calculated the proper temperature, if the point in time were off by even a few seconds during this 7 to 9 hour process, the wrong temperature would be compared to the reference temperature and the Logger would fail.
Is there a test that can be performed to determine if an FRB battery is being conditioned properly?
If the FRB battery conditioning procedures are followed per the instructions, the batteries will be properly conditioned. The following procedure was suggested by our Quality Assurance Department for those wishing to monitor the battery conditioning process:
When conditioning a battery for an FRB Logger, connect a digital voltmeter to the battery leads, and then connect the depassivation clip. Observe the voltage drop as the internal resistance of the battery's passivation layer prevents much current from flowing. Often it can start out as low as 0.5 volts when the clip is first connected. Over the next few minutes, you can watch the voltage increase as the passivation layer is eliminated and the battery's resistance decreases. For standard temperature batteries (the rectangular ones), after 3-5 minutes, the voltage should climb to 2.4 volts or better. Low temperature batteries (the round ones) usually take a little less time. Disconnect the depassivation clips when the voltage climbs to about 2.4 volts. If it takes more than about 5 minutes to achieve this voltage, there is something wrong with the battery, so do not use it.
After the depassivation clip is disconnected, the voltage will immediately climb, but will actually take several minutes after the load has been removed before it will climb all the way up to its normal voltage for a new battery, about 3.68 to 3.70 volts for standard temperature batteries, about 3.85 to 3.90 volts for the round, low temperature batteries. Even if this higher voltage has not yet been achieved, it is still okay to install the batteries into the Loggers; the circuit will normally run on voltage as low as 2.4 to 2.5 volts. Always run the "Test Logger" routine from the software right after installing a new battery. When it first powers up, the Logger will be in a high power mode. Once the Logger has been programmed and read (which is what the "Test Logger" function does), it will go into a very low power mode and consume very little power from the battery for storage until the Logger is used next.
At Mesa, we use an internal acceptance specification of 3.50 volts or better, under a 1500 Ohm load to determine whether a battery is "good". The reading should be taken about 15 seconds after applying the load. If the voltage goes down but then up when the load is applied, then the battery was passivated. How much it goes down and then how far it comes up is determined by how passivated the battery was. If the voltage just goes down steadily when the load is applied, then the battery was not passivated.
Is Mesa Laboratories ISO certified?
Mesa's Medical Division is qualified to the ISO 13485/13488 standard and is registered as a Medical Device manufacturer with FDA, under registration number 1720309 and with Canada (CMDR). Appropriate portions of this rigorous quality control system are also utilized by the DataTrace Division.
The DataTrace Compliance and Certification (form 339) certifies not only the Software Validation but also the FDA-based quality system for DataTrace and the NIST-traceable calibration system. Unlike an ISO certificate, it gives more detail about our quality system. Our Quality Assurance Manual is designed to substantially comply with all the criteria of ISO 9001. This document is revised to keep it current with new products, changing requirements, and technologies.
Is DataTrace equipment rated Intrinsically Safe and by which agencies?
All DataTrace Loggers are certified intrinsically safe by CSA (Class I, Groups A, B, C, and D; Class II, Groups E, F, and G; Class III; Enclosure 4) and by LCIE in France (EEx ia IIC T4). The LCIE certification complies with EN 50014(1992), NF EN 50014(1993), EN 50020(1994), NF EN 50020(1995). DataTrace PC Interfaces are not used in hazardous environments and therefore are not certified intrinsically safe.
Does DataTrace equipment carry a CE mark?
Yes, all of our DataTrace equipment (Loggers and PC Interfaces) carry the CE mark. The specific requirements relate to the following EC Standards or Norms for Electromagnetic Compatibility: EN 55022 and EN 50082-2.
Can I use boiling water or an ice bath to verify my Logger?
Assuming that proper care is taken in the preparation of these processes, it is possible to verify Loggers in these mediums, but it can be difficult to obtain the stability and uniformity required using "common materials".
First it must be recognized that water boils at 100 °C and freezes at 0 °C only at sea level. Second, the water used must be ultra-pure. Impurities will change both the boiling point and freezing point observed. Finally, the higher in altitude (above sea level) that the verification is performed, the lower the boiling point of water. All of this suggests that a well calibrated reference standard should be used to verify the actual target temperature even in these "known" environments.
The vessel used should be one that is more stable and uniform than a pot on a hotplate. A liquid medium that is not well stirred or isolated from the outside environment will be neither stable nor uniform. Furthermore, the bottom, sides and top can be at significantly different temperatures than the middle.
Can the Logger probe tip be made shorter than 23 mm (25 mm for MPIII)?
Physically, it is possible to make the tip 13 mm, less than that creates problems with welding the probe tube, and also, the installation of the sensor into the probe tip, especially the RTD.
Of greater concern is the thermal affect caused by the base on the temperature observed by the sensor. In the Micropack MPIII, tests found in certain environments that the base acted to influence the sensor's temperature readings. Obviously, this depends on the environment and how the Logger is fixed in the product/process, but there was an observable impact in many situations.
Obviously, the MPIII is much smaller and less of an impact would be expected, but we expect an observable impact in certain situations where the probe tip is less than one inch in length.
Can the MPIII Logger be used in a microwave?
Our experience with MPII Loggers in a microwave environment has been mixed, some good, some bad. In general, the successes have been with applications where the product is homogeneous, with high fluid content, and where the Logger is completely inside the product. An example of a good application would be pate. An example of a bad application would be pasta drying.
Microwave impacts on MPIII should be similar to previous Logger versions, with one significant exception - the windows on the side of the body. These become windows that provide direct access for the microwaves to the electronics. This would be bad. If the application were to be tried, the windows must be shielded, either with a cover or at least by positioning them to face away from the microwave source.
What is the difference between a thermocouple, an RTD, and a Thermistor?
A thermocouple is based on the principle that an electromagnetic force (emf) is generated when heat is applied to the junction of two dissimilar metals (sensing junction). At the other end of the wires, usually as part of the input instrument, is another junction, called the reference junction. The temperature is inferred based on the emf difference between the sensing junction and the reference junction, which is at a known temperature.
Advantages of thermocouples:
- Low cost, rugged, small size/fast response, wide temperature range, and reasonably accurate
Disadvantages of thermocouples:
- Weak emf signal, calibration affected by temperature gradients and material contaminants, affected by electrical interference, calibration drifts following calibration
An RTD is based on the principle that the electrical resistance of a metal increases as its temperature increases. The RTD sensing element consists of pure metal (frequently platinum) and shows a small positive, linear change in resistance per degree of temperature change.
Advantages of RTDs:
- High repeatability and stability, high accuracy over wide range, rapid response, and small sensor size
Disadvantages of RTDs:
- High cost, fragile, susceptible to emf interference and self-heating, not suitable for extremely high temperatures
A thermistor is a thermally active resistor composed of metal oxides normally encapsulated in epoxy or glass. A typical thermistor shows a large negative, nonlinear change in resistance per degree of temperature change. A thermistor's resistance drops dramatically and non-linearly with temperature.
Advantages of thermistors:
- Inexpensive, long-term stability, high accuracy, temperature coefficient is greater than metals, rugged, small size/fast response, high sensitivity, senses at a single point, and requires simple circuitry
Disadvantages of thermistors:
- Temperature resistance curve is non-linear, relatively narrow range, and not suitable for high temperatures
How can I clean the humidity sensor on my Humidity Logger?
The short answer is that the Humidity Logger's sensor can not usually be cleaned. The sensor's manufacturer does not recommend attempting to clean the sensor, either chemically or by any form of scrubbing as it is likely to cause damage. The humidity sensor has a moisture-sensitive polymer on a ceramic substrate. These components are extremely thin and are sensitive to abrasion. Damage to, or removal of the polymer will destroy the sensor. At best trying to clean the sensor will worsen the affects of the contamination.
The best approach if you believe the Logger's sensor has become contaminated is to perform a humidity verification. If the calibration is determined to be out of specification, either do a field calibration on the existing sensor replace the Logger's sensor with a new sensor, or return the Humidity Logger to the factory for a refurbishment.
Why are the temperature values of my Humidity Logger different from my Temperature Logger?
The environmental temperature recorded by a temperature-only Logger and the temperature value recorded by a Humidity Logger can be significantly different, and that is expected. The primary purpose of a temperature-only Logger is to measure the environment next to the sensor; regardless of what that environment is (e.g., air, liquid, meat, etc.). The temperature sensor's primary purpose in a Humidity Logger is not to measure the environment; it is to measure the temperature of the humidity sensor. That is the meaning of "temperature compensation". The compensation corrects the humidity reading for the actual temperature the humidity sensor is experiencing - the temperature of the humidity sensor. The environmental temperature is not relevant to the humidity reported.
This is why the temperature reported in a changing environment will be different between a Humidity Logger and a Temperature-only Logger. As the temperature in the environment stabilizes, the temperature readings will become closer, eventually becoming the same.
Again, keep in mind that the primary purpose of the Humidity Logger is to provide accurate humidity values and the primary goal of the Temperature Logger is to provide accurate temperature values. The methods of accomplishing these goals are not the same for both types of Loggers, as indicated above.
Can my Pressure Logger work in a vacuum?
Yes. Also, our Logger can tell them how much vacuum is pulled as long as they know what the pressure was BEFORE they pulled the vacuum.
All you need to remember is that your Logger collects ABSOLUTE pressure. In absolute pressure there is no negative pressure, it starts at 0 bar and goes up from there. If you want to know how much of a vacuum is pulled you need to know what the pressure was before the vacuum was pulled and what the pressure fell to after you pulled the vacuum. For example, normal atmospheric pressure (at sea level) is 1.013 bar. If you pull a vacuum and the Logger reads 400mbar, then you have a "vacuum" that is at 400mbar.
How can I clean the pressure sensor on my Pressure Logger?
Cleaning of the pressure sensor is possible if extreme care is employed. Under no circumstances should swabs, picks, or any other instrument or tool be used in contact with the diaphragm. The diaphragm should never be touched; even the slightest pressure will adversely impact the device and its accuracy.
To start the cleaning process, carefully remove the protective cap by unscrewing it from the probe base.
- For any coating or process residue adhering to the diaphragm, it is best to soak it off before it dries.
- For cases where the coating or process residue adhering to the diaphragm has already dried, let the Logger soak in warm water with a mild detergent until the contamination softens. Then rinse it off with a LOW PRESSURE water stream.
- In severe cases of contamination, a solvent may be necessary. Use a solvent for the specific contamination material. Since the diaphragm is stainless steel, most solvents will not affect it. If you have a question regarding a specific solvent, contact us.
It is critically important that the diaphragm is not touched, scrubbed, picked at, pushed on or probed. This can cause permanent damage.
How quickly does my Pressure Logger respond to pressure changes?
The Pressure Logger's pressure sensor responds to changes in pressure almost instantly (< 1 second). The observed pressure will be accurate providing that the Pressure Logger is in an isothermal (stable temperature) environment. If the temperature is changing, the observed pressure can be in error by as much as 150mbar.
Why are the temperature values of my Pressure Logger different from my Temperature Logger?
The environmental temperature recorded by a temperature-only Logger and the temperature value recorded by a Pressure Logger can be significantly different. And that is expected. The primary purpose of a temperature-only Logger is to measure the environment next to the sensor; regardless of what that environment is (e.g., air, liquid, meat, etc.) The temperature sensor's primary purpose in a Pressure Logger is not to measure the environment; it is to measure the temperature of the pressure sensor. That is the meaning of "temperature compensation". The compensation corrects the pressure reading for the actual temperature the pressure sensor is experiencing - the temperature of the pressure sensor. The environmental temperature is not relevant to the pressure reported.
This is why the temperature reported in a changing environment will be different between a Pressure Logger and a Temperature-only Logger. As the temperature in the environment stabilizes, the temperature readings will become closer, eventually becoming the same.
Again, keep in mind that the primary purpose of the Pressure Logger is to provide accurate pressure values and the primary goal of the Temperature Logger is to provide accurate temperature values. The methods of accomplishing these goals are not the same for both types of Loggers, as indicated above.