Temperature calibration should not be confused with temperature simulation. Electrical temperature measurement uses a primary temperature element, usually a thermocouple or RTD, plus an electrical signal conditioner which will take the input from the primary device, linearise it, and present it as temperature. Calibration of this signal conditioning circuitry can be done with a temperature simulator, but calibration of the complete assembly or the primary element, requires the application of a reference temperature. Today this is often done using a dry-block calibrator.

We represent Ametek Denmark, better known as Jofra, developers of the dry-block temperature calibrator.

Dryblock calibrators are becoming the mechanism of choice for field and workshop calibration of temperature instruments, since their introduction by Jofra in the eighties.

However, it is only recently that a standard calibration guideline, EA-10/13 has been set up by the European Cooperation for Accreditation. For the first time, the whole question of dryblock accuracy has been explored and quantified.

In the past, most dry-blocks, even those from reputable manufacturers, were inadequately specified. Now that the range of uncertainties has been defined, there is no longer any excuse for “specmanship”.

Product Range:
Jofra’s current range is split into 4 models, and each model typically has 3 temperature ranges. The usual top limit is 650ºC, driven by the operating limits of PRTs. The lower range is dual heating/cooling using Peltier elements, with maximum temperatures between 125 and 155ºC. The mid range unit is typically 320ºC. All models are digital, and include software and serial links.

ATC Range:
The ATC (Advanced Temperature Calibrator) is a benchmark calibrator available in two categories.
Class B: This version offers electrical inputs for most electrical temperature signals, eg thermocouples, RTDs and transmitters, but perhaps more importantly, this version can have a variety of jobs defined and downloaded from a host PC, so that the ATC-B can be taken to a remote location, left to run a procedure on an electrical temperature sensor completely automatically, then taken back to the host PC to upload the results for archiving and document generation. The ATVC-B also has capacity to read an external SPRT for maximum accuracy, to 0,04ºC in the 156/157 models.
Class A: This version is, apart from the Class B, the most accurate in the Jofra range.

Models:
ATC 156: This is a dual range unit with a top limit of 155ºC, using the latest generation of Peltier elements. The minimum temperature attainable at 23ºC ambient is –24ºC.
ATC 157: This is a lower range version of the 156. The minimum temperature attainable at 23ºC ambient is –45ºC. Lower temperatures are possible at lower ambient temperatures.
ATC 320: This is a mid-range unit with a top limit of 320ºC. The practical minimum usable temperature is stated as 33ºC, as cooling below 33°C is dependent on convection and can take a long time.
ATC 650: This is the top range unit with a limit of 650ºC. The practical minimum usable temperature is stated as 33ºC, as cooling below 33°C is dependent on convection and can take a long time.
Click here ATC for data sheet:

ITC Range:
The ITC (Industrial Temperature Calibrator) is a cross between the entry level CTC and the ATC, built on the CTC chassis, but incorporating some features from the ATC. It is again available in three models.
ITC 155: This is a dual range unit with a top limit of 155ºC, using the latest generation of Peltier elements. The minimum temperature attainable at 23ºC ambient is –23ºC.
ITC 320: This is a mid-range unit with a top limit of 320ºC. The practical minimum usable temperature is stated as 33ºC, as cooling below 33°C is dependent on convection and can take a long time.
ITC 650: This is the top range unit with a limit of 650ºC. The practical minimum usable temperature is stated as 33ºC, as cooling below 33°C is dependent on convection and can take a long time.
Click here ITC for data sheet:

CTC Range:
The CTC (Compact Temperature Calibrator) is the entry-level bench calibrator, available with two insertion depths on the heating only versions, the deeper one of 200mm intended for liquid filled systems.
CTC 140A: This is a dual range unit with a top limit of 140ºC. The minimum temperature attainable at 23ºC ambient is –17ºC.
CTC 320A/B: This is a mid-range unit with a top limit of 320ºC. The practical minimum usable temperature is stated as 33ºC, as cooling below 33°C is dependent on convection and can take a long time.
CTC 650A/B: This is the top range unit with a limit of 650ºC. The practical minimum usable temperature is stated as 33ºC, as cooling below 33°C is dependent on convection and can take a long time.
Click here CTC for data sheet:

ETC Range:
The ETC (Easy Temperature Calibrator) is a portable unit designed for quick checks in the field. Unlike the other models this is only available in two ranges.
ETC 125A: This is a dual range unit with a top limit of 125ºC. The minimum temperature attainable at 23ºC ambient is –10ºC.
ETC 400A: This is a mid-range unit with a top limit of 320ºC. The practical minimum usable temperature is stated as 28ºC, as cooling below 28°C is dependent on convection and can take a long time.
Click here ETC for data sheet:

High Temperature Calibrator:
The normal range limit in the above model ranges is 650 ºC, limited by the PRTs used as references. The 1200SE overcomes this problem by using a special ultra-stable thermocouple, and offers temperatures to 1200ºC.