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Brand: Isotech
Isotech TTI-22 High Accuracy Resistance Thermometer
Description
A two-channel resistance thermometer reading to 0.001 degrees C
The Isotech TTI-22 is a high-accuracy thermometer for industrial and secondary resistance thermometry, measuring from -250 to 960 degrees C (0 to 440 ohm) with 100 ohm industrial probes or 25.5 and 100 ohm SPRTs to ITS-90. Isotech quotes an instrument measurement uncertainty of 0.001 degrees C for a 100 ohm PRT and a resolution of 0.0001 degrees C (0.00004 ohm). It has two input channels, no mechanical relays, weighs 1.8 kg and runs for more than 10 hours from two AA cells. It is intended as a reference standard beside liquid calibration baths and dry blocks, and for demanding stand-alone measurement.
Technical specifications
| Parameter | Specification |
|---|---|
| Inputs | 2 channels; Pt100 (BS EN 60751 / IEC 751) or 25.5/100 ohm SPRT to ITS-90 |
| Measuring range | -250 to 960 degrees C (0 to 440 ohm) |
| Resolution | Temperature 0.0001 degrees C; resistance 0.00004 ohm (40 micro-ohm) |
| Uncertainty of measurement | Temperature 0.001 degrees C (100 ohm PRT); resistance 0.4 milli-ohm at 20 degrees C; instrument only |
| Measuring current | 0.41 mA; self-heating test current 0.29 mA |
| Measuring time | 1.44 seconds for both channels |
| Internal reference resistor | 380 ohm, TCR plus or minus 0.3 ppm per degree C, stability plus or minus 5 ppm per year |
| Interfaces | RS232, Ethernet, built-in web server for simple temperature display |
| Ambient temperature | 10 to 30 degrees C |
| Power | 7.5 VDC, 250 mA adaptor, or 2 x AA batteries (typically more than 10 hours) |
| Case size and weight | 190 W x 112 H x 240 D mm; 1.8 kg |
Measurement method and software
Each reading performs a zero point and gain correction, and the switched-polarity DC measuring current of about 0.4 mA removes thermal EMFs. The sensor is compared with the stable internal reference resistor; for a Pt100 at 0 degrees C the annual absolute stability is typically 1.3 mK. The unit can store up to 30 probe calibrations with their expiry dates and warns when a calibration is overdue, shows measured and average values with standard deviation, and can display the ratio of the two channels as older thermometry bridges did. Cal Notepad software is included and the unit works with Isotech I-Cal Easy for automated comparison calibration.
Probes, ordering and documents
Isotech recommends probes such as the 909/100, 670SQ/100, 935-14-16 and 935-14-95L and H. The overall uncertainty depends on the probe model and temperature range, and for most uses the instrument contribution is negligible compared with that of the calibrated probe. Related Isotech instruments on this site include the Isotech milliK precision thermometer and semi-standard PRTs; more are under Temperature Instrumentation. The attached datasheet gives the full specification. State the probes, certificate (traceable or UKAS) and quantity when requesting a quotation.
Datasheets & Documents
- Datasheet Isotech TTI-22 True Temperature Indicator datasheet Download
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About brand
Isotech has made temperature calibration equipment in Southport, United Kingdom, since 1980. Its instruments are found in calibration laboratories and in instrument workshops that check thermocouples, RTDs and temperature transmitters. Seven Star LLC lists Isotech dry block calibrators, reference thermometers and precision readouts and supplies them to calibration laboratories and plant instrument maintenance departments in Oman.
Isotech calibrators and thermometers listed here
Two dry block calibrators are listed: the portable Jupiter 4852, a block for the higher temperatures at which thermocouples and platinum resistance thermometers are checked, and the Europa 4520 from the Isocal-6 family, which covers -45 to 140 °C and can be converted with accessories into a stirred liquid bath. Alongside them are Isotech semi-standard PRTs, used as reference platinum thermometers, and the milliK precision thermometer, which reads PRTs, thermistors and thermocouples. Together these form a working calibration setup: a heat source, a reference probe and a readout.
Ordering Isotech equipment: what we need
For an Isotech dry block calibrator, tell us the temperature range you must cover, the diameters and lengths of the sensors under test, the insert drilling you need and the mains voltage. For a reference PRT, state the temperature range, sheath length and whether a calibration certificate from the manufacturer is required. GCC laboratories should also name the accreditation requirement the certificate has to meet.
Browse Isotech products by category: Temperature Instrumentation.
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Frequently Asked Questions
What accuracy does the TTI-22 state?
Measurement uncertainty of 0.001 degrees C for a 100 ohm PRT, instrument only.
What sensors can it measure?
Industrial Pt100 probes and 25.5 or 100 ohm SPRTs to ITS-90.
How many input channels are there?
Two, measured in 1.44 seconds for both channels.
How is it powered?
By a 7.5 VDC adaptor or two AA batteries, for more than 10 hours of use.
Which communication ports does it have?
RS232 and Ethernet with a built-in web server.
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