TME "IRCALkit" IR Temperture sensor Test and Calibration kit - By Fraser - Page 1
Forum section: electronics / general

author: Fraser
author_rank: Super Contributor
timestamp: February 27, 2020, 04:37:53 pm
content: OK, an unusual bit of IR temperature measurement test and calibration kit for those interested in such things.I had previously come across this piece of test equipment on eBay under another brand name and at a very high asking price. This unit appeared on eBay recently under its OEM branding of TME and at a more reasonable price. The price was still too high for my liking so some negotiation took place and I became the units new owner.So what is this piece of test equipment ?The equipment is titled "IRCALkit" and is manufactured by the reputable TM Electronics (TME) in the UK.https://www.tmethermometers.com/The kit is used to check the serviceability and accuracy of IR temperature measurement devices. It comprises the following parts:1. TME 2040 precision thermistor thermometer2. TME Infrared Calibration probe3. TME air temperature probe4. PW00965 multi voltage power supply (set to 12V/500mA by default)5. Hard Case with foam insertThe TME 2040 is an accurate thermometer that can either measure air temperature, using the provided air thermistor probe, or the temperature of the 50mm aluminium plate that is mounted on the Infrared calibration probe.So what is the Infrared Calibration Probe ?It is a pretty standard TME probe handle with coiled lead and stainless steel probe shaft. At the end of the probe shaft there is a 50mm diameter anodised aluminium disk that is attached to a silicone insulated heater pad. The pad is rated at 12V/2W. There is a precision thermistor contained somewhere within the head assembly as well. The coiled lead is terminated in the common 1/4" headphone plug that is used with the TME 2040. Also coming from that same 1/4" plug shell is a power cable from the PW00965 power supply. The Power supply is a common multi voltage 'universal' type and is rated at 500mA maximum load.The IR calibration probe may be used in the 'unpowered' or 'powered' mode. In the unpowered mode it measures the temperature of the aluminium disk, which would normally be at ambient temperature. This creates an ambient temperature "Blackbody" plate. In the powered mode of operation the power supply provides the heating element in the probe head with 12V by default. The supplied voltage may be reduced using the output voltage selector on the power supply. The emission plate temperature is related to the voltage applied to the heater so maximum temperature will be achieved on the 12V setting and minimum temperature on the 3V setting.The IR calibration probe has no temperature stabilisation and is purely an "open-loop" heater that reaches thermal equilibrium. The thermometer informs the user of the actual emission plate temperature at any point in time so that it may be compared to that being measured by the IR measurement device under test. Simple, but effective.FLIR make a larger version of this IR calibration device that is desk mounted and has a large aperture and emission plate in its case. It is also an open loop heater design and the user applies a voltage to the input terminals according to a supplied temperature chart in order to achieve close to the desired temperature for a particular test. A thermocouple is provided on the emission plate for the user to use their own thermometer. The unit is used to calibrate TAU cores when fitting different lenses to them. The cost of the FLIR unit is around £1300 and you have to supply your own power supply and thermometer !It goes without saying that both the TME and FLIR open loop heater Blackbody solutions are far from optimal for a serious calibration blackbody, as used on a calibration bench. The theory behind the design is reasonably sound however. Provided the user knows the emissivity of the emission plate and the true temperature on the surface of the plate, the units may be used to calibrate thermal measuring equipment that does not require specific and precise temperatures to be created as part of its calibration process. My FLIR SC4000 science camera calibration routine just requires that I point the camera at the Blackbody and tell it the emissivity and temperature of that thermal energy source. It works the rest out itself.I powered the TME IRCALkit for a very quick test. After 15 minutes I checked the temperature that the probes emission plate had reached and stabilised around. It was at 62 Degrees C in an ambient temperature of around 16C. That is plenty hot enough for many calibration tasks that involve thermal measurement equipment that can measures such a temperature, or lower. I shall carry out further testing of the unit when time permits and will include a thermal image of the IR Calibration probe whilst operating.For now, I will leave you with some pictures and datasheets. Will it be good, bad or somewhere in between ? It is an open emission plate so air movement will effect it but may be captured by the thermometer measurements. We shall see.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: February 27, 2020, 04:39:33 pm
content: IRCALkit documents.....

author: Fraser
author_rank: Super Contributor
timestamp: February 27, 2020, 04:41:27 pm
content: Pictures of my unit during its brief test......

author: Fraser
author_rank: Super Contributor
timestamp: February 27, 2020, 04:58:43 pm
content: The FLIR 4" Open Loop heater Blackbody for use by manufacturers with the TAU cores when calibrating lenses.Yours for only US$1795I also attach the datasheet/manual that provided the voltage/temperature cross reference.

author: Fraser
author_rank: Super Contributor
timestamp: February 28, 2020, 02:57:22 pm
content: I have a few minutes spare so here is the testing regime needed fir the weird TME IRCALkit. There are some areas of the kits performance that need to be tested and verified.1. Accuracy of the IR probe thermistor and 2040 thermometer.This is a relatively simple check carried out with the probe unpowered and reading ambient temperature. The 2040 temperature reading is compared to that of a PT100 based thermometer of known accuracy. If the readings do not tally (within specification) the TME air probe will be substituted fir the IR probe and the test repeated. Of the error in reading is repeated then it is a thermometer calibration error that requires further investigation.2. Accuracy of the IRCALkit when at operating temperatureThe IR probe will be powered with a stable 12V DC supply for this test. After a 30 minute warm-up period fir the probe to reach thermal equilibrium, a PT100 surface contact probe and thermometer of known accuracy will be used to measure the probes emission plate temperature and the reading compared to that shown on the 2040 thermometer. The readings should tally within the accuracy specifications of the thermometers. If not, further investigation is needed. Further tests at lower probe supply voltage may also be carried out to check the accuracy of the 2040 thermometers calibration curve.3. Emissivity of the IR probe emission plate.This is an interesting test as I have my doubts about the manufacturers claim regarding the probes emissivity. The emission plate is stated as being Anodised Aluminium and is coloured black. The manufacturer states that the emissivity of this plate is “nearly 1” and should be treated as such in any calculations to correct readings from IR sensors set for lower target emissivity. An example is even provided of a sensor set to 0.95 emissivity. This rang alarm bells for me as black anodised aluminium has an emissivity closer to 0.80 at best. Unless the emission plate has beef coated with a high emissivity lacquer I cannot see how it can possibly achieve anything close to 1.0.I shall test the emissivity of the IR probes emission plate using several Industrial grade IR thermometers and a thermal camera of known accuracy. The Industrial IR thermometers that I will use are professional, very accurate products from Minolta-Land and Exergen. These IR thermometers are more accurate than most thermal cameras and have adjustable emissivity. The temperature of the IR probe emission plate will be monitored with a contact thermal sensor in both the unpowered (ambient) and powered (12V D.C) modes. The emission plate will be viewed at close range by IR thermometers of known accuracy and the emissivity setting adjusted until the temperature reading on the IR thermometer matches that shown on the emission plate contact thermometer. The emissivity of the emission plate will then be known within the limitations of the simple test that I am carrying out. The test will be repeated with several different IR thermometers and also a FLIR E40(60+) for comparison.I strongly suspect that the emission plate emissivity will not be “close to 1”. I may decide to coat the emission plate with high emissivity Matt black paint as that will give a better emissivity, but will be prone to damage as the probe plate is unprotected. We shall see.Well that is all for now. More from me when I get time.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: February 28, 2020, 03:13:24 pm
content: An interesting article on the emissivity of Aluminium surfaces and how it may be improved.https://assets.markallengroup.com//article-images/1243/mn-anode.htmThe best they can achieve with surface treatment rather than coating is around 0.9Fraser

author: Fraser
author_rank: Super Contributor
timestamp: February 28, 2020, 03:19:11 pm
content: An interesting emissivity table that includes black anodised aluminium and two samples showed slightly different emissivity. I have seem many emissivity values for black anodised aluminium ranging from 0.77 to 0.85 so it is a very difficult material to asses without the real world practical testing that I have detailed above. There are many variables “in play” with anodised aluminium surfaces. This is where high emissivity coatings are superior. The coating, if applied correctly, has a more predictable emissivity.https://www.design1st.com/Design-Resource-Library/engineering_data/ThermalEmissivityValues.pdfFraser

author: Fraser
author_rank: Super Contributor
timestamp: February 28, 2020, 04:23:13 pm
content: Regarding the Power Supply unit supplied with the kit ..... I am not very keen on it. It is a simple universal type with fixed voltage steps that may only be changed by unplugging it from the wall socket. A wise requirement bearing in mind the type of regulation circuit often used in such simple power supplies, but not very convenient for the IR probe use.I decided that I would source a compact variable voltage power supply for the IRCALkit even before it had arrived. I wanted something small, cased and simple. Whilst searching for such, I discovered the world of Tattoo pen power supplies ! These are commonly compact, decent current capability and variable voltage output. Looking at a few, there were the usual iffy ones with metal cases that were so thin that the metal was bent even in the official advertising pictures ! I searched fro something basic that looked like it would not fall apart in use. I would carry out the usual safety checks once I received it and make any necessary modifications. Many Tattoo pen power supplies use 1/4" headphone connectors for pen output and foot pedal. I will be bypassing the foot pedal but the 1/4" plug requirement matches the connector used in the IRCALkit so that can remain. I chose a couple of the tattoo power supplies in the end as I am interested in just how good or bad they are inside the casing. They are cheap enough that they would lend themselves to many non demanding tasks that I have in mind. I have several heater based projects that care not how noisy the power supply rails are, just so long as their voltage and current needs are metI have several decent lab power supplies but I also wanted something relatively cheap and simple for powering some Blackbody projects that I will be working on. Whilst looking for a power supply for the IRCALkit I found a very affordable Top Power STP3005 30V/5A hobby lab power supply for around £25 from UK stock. I thought it would be total rubbish at that money but some posts on its and internal views made me reconsider my negative attitude towards it. For driving resistance heater circuits and Peltier elements I was not too concerned about noise and ripple on the output and I know a previous post on this forum highlighted some pretty impressive switching transients getting through to the output terminals ! I may tidy that up a bit but this power supply will never be connected to anything sensitive or expensive so such bad behavior is of little concern to meFor £25 delivered, it is silly cheap. I have a professional Blackbody 19" rack controller unit that contains a complete, remote controlled Lab Bench supply, complete with display and knobs that will never be seen by the user. The control knobs are locked and the remote control input on the rear is used. I was somewhat surprised to see a whole lab power supply inside the controller as a open chassis or modular type is more common. That lab power supply is Canadian and costs a small fortune. The manufacturer of the Professional Blackbody clearly decided that it was the power supply for the job and the fact that it was a bench unit was of little consequence ! Food for thought on future projects when complete bench power supplies from China can be so affordable. No one say they have to be used in the manner originally intended ehThe first of the tattoo power supplies and the Top Power 3005 hobby lab power supply have arrived and I am just awaiting the second tattoo power supply coming from Singapore. The Tattoo power supplies were £10 and £13 each. The one coming from Singapore looks perfect for the IRCALkit as it is just a rectangular box with an LED display, voltage setting knob and two I/O sockets. Nice an simple looking. The other tattoo unfortunately has an unsightly tattoo related motif on the top. I can live with it thoughDespite the unwelcome motif, the unit has feature of two voltage setting pots and two outputs fro dual pen use. The front panel push button selects which output and voltage setting potentiometer is active.Pictures attachedFraser