Ametek ATC-250B Advanced Temperature Calibrator
Dry Block with Liquid Bath Configuration

    ATC-250 Series Features:
  • Temperature range 20 to 250°C (82 to 482°F)
  • Use as liquid bath or large diameter dry-block calibrator.
  • Dual-zone block ensures good temperature homogeneity in the critical calibration zone.
  • Stand-alone operation eliminates need for secondary equipment and PC.
  • Universal inputs handle multiple type temperature sensors.
  • RS232 communication and JOFRACAL calibration software are included in the standard delivery.
    ATC-250B Specific Features:
  • Highest accuracy
  • “SET-Follows TRUE”
  • Switch test
  • Sensor under test and reference probe input
  • “As Found/As Left”
  • Perform or read calibration directly from instrument

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Ametek ATC-250B Shown

Product Information
Datasheet 1.65 MBpdf
Software Information
Ordering Guide
Ordering Info Jump to Product Models, Prices, Accessories, and Ordering Information
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The ATC-250 features the unique dual-zone heating block - designed for optimum performance and superior temperature homogeneity throughout the block. This new design has a performance equivalent to a liquid temperature bath.

The ATC-250 dry-block calibrator may be used to perform fully automatic calibration routines without using an external computer. Use the computer for full upload and download capabilities. The ATC-250B is supplied with inputs for external reference sensors and for sensors-under-test. All ATC calibrators feature RS232 serial communication and standard delivery also includes the JOFRACAL calibration PC software.

Unique temperature performance
The ATC series of calibrators provide precision temperature calibration of sensors; whatever the type or format. This is accomplished through an innovative dual-zone heating technology.

Both the ATC-250 features dual-zone heating technology. Each heating zone is independently controlled for precision temperature calibration. The homogeneity in the lower part is close to that of a laboratory liquid bath. The lower zone ensures optimum heat dissipation throughout the entire calibration zone. The upper zone compensates for heat loss from the sensor-under-test and from the open top. This design also eliminates the need for insulation of the sensors-under-test and makes it possible to calibrate liquid-filled and other mechanical sensors.

MVI (Mains power Variance Immunity) - Improved temperature stability
Unstable mains power supplies are a major contributor to on-site calibration inaccuracies. Traditional temperature calibrators often become unstable in production environments where large electrical motors, heating elements, and other devices are periodically cycled on or off. The cycling of supply power can cause the temperature regulator to perform inconsistently leading to both inaccurate readings and unstable temperatures.

The ATC-250 calibrator employ the MVI, thus avoiding such stability problems. The MVI circuitry continuously monitors the supply voltage and ensures a constant energy flow to the heating elements.
Features ATC-250 Series Details
Set temperature The “Set temperature” feature allows the user to set the exact desired temperature with a resolution of 0.01°.
Instrument setups The ATC series allows the user to store up to nine (9) complete instrument setups. You may store all sorts of information including temperature units, stability criteria, use of external reference sensor, resolution, sensor-under-test (SUT), conversion to temperature, display contrast, etc. The setup may be recalled at any time.
Stability indicator A stability indicator shows when the ATC calibrator has reached the desired temperature and is stable. The user may change the stability criteria, external reference and the sensor-under-test quickly and simply. The stability criteria is the user’s security for a correct calibration. A count-down timer is displayed next to the temperature read-out.
intuitive operation
All instrument settings can be performed from the front panel. The heat source is positioned away from the panel which helps protect the operator.

The keyboard is equipped with five, positive feedback function keys. They correspond to the text in the display and change functionality based on instrument operations. There are also dedicated function keys with permanent functions.

The easy-to-read, backlit display is large with a high contrast that is readable even in high ambient light conditions. The display is easily read from all angles and from a distance without parallax problems. The display also features icons which help identifying instrument conditions and operational steps, making it more intuitive to work with.
Auto-stepping Up to 20 different temperature steps may be programmed including the hold time for each step. Upon completion of an auto step routine, the user can easily read the results for the sensor-under-test. Up to five (5) auto step results are stored.
Liquid bath/
large diameter insert
The ATC-250 is fitted with a 150 mm (5.9 in) deep well with a diameter of 63.5 mm (2.5 in) can be used both as dry-block calibrators and as liquid calibration baths with a magnetic stirrer.

A liquid bath and a dry-block diameter of 63.5 mm (2.5 in), which is twice the size of any other Ametek dry-block calibrator, are both new in the JOFRA product range. With these options it is now possible to calibrate even more temperature sensors at the same time and to calibrate large as well as odd sizes and shapes of sensors, which is not possible to calibrate in the remaining product range.


Highest accuracy
Built-in reference thermometer for use with an external probe. This feature allows one instrument to provide the freedom and flexibility to perform calibrations at the process site while maintaining a high accuracy.

“SET-Follows TRUE”
The “SET-Follows TRUE” makes the instrument tune in until the temperature of the external reference “TRUE” meets the desired “SET” temperature. This is used when it is critical that the temperature of the calibration zone matches the desired temperature when measured with accurate external reference sensors.

This feature is ideal when calibrating gas correctors or other custody transfer applications. It is also extremely useful to calculation procedures

Reading of sensor-under-test”
Built-in converters (inputs) enable measurement of virtually any type of temperature sensor including:
thermometers (RTD)
thermocouples (TC)
transmittersmilliamps (mA)
voltage (V).
The ATC calibrators can be user-programmed for completely automated temperature calibrations. Once the unit is programmed, the instrument operates itself by performing the configured calibration routine. All calibration data is stored and available for uploading and generating exact calibration certificates or reports.

Switch test
Users may perform a thermoswitch test and find “Open”, “Closed” and the hysteresis (deadband) automatically. The instrument retains the last five tests.

As found/as left
Automatically handles “As Found/As Left” calibrations. The calibrator stores both results. The first performed calibration is “As found” and the last performed calibration is the “As left”, regardless of the number of calibrations/adjustments that may have been made in between.

Users may perform or read the results of the calibration tasks directly on the instrument. When calibrating an indicating device, users may key in the results during or after the test. Using the “Calibration info” function, the user may view the complete calibration task, including the “Scenario” be-fore the calibration takes place.

ATC-250 Series Specifications
Main specifications
Voltage 115V(90-27)
Frequency, non US deliveries 50 Hz ±5, 60 Hz ±5
Frequency, US deliveries 60 Hz ±5
Power consumption (max) 1150 VA
Temperature range
(dry block)
28 to 250°C / 82 to 482°F
Temperature range
Liquid Bath)
28 to 250°C / 82 to 482°F
Resolution Selectable 1º or 0.1º
Stability +0.02°C / +0.036°F
Measured after the stability indicator has been on for 15 minutes. Measuring time is 30 minutes.
Time to stability 15 Minutes
Resolution 1° or 0.1° or 0.01°
Accuracy with Internal Reference Sensor +0.28°C / +0.50°F
Radial Homogeneity
(difference between holes)
Dry Block 0.05°C / 0.09°F
Liquid Bath 0.025°C / 0.045°F
Immersion depth Dry Block 150 mm / 5.9 in
Liquid Bath 150 mm / 5.9 in
Well Diameter 63.8 mm / 2.51 in
Heating time 50 to 250°C/122 to 482°F 11 minutes
Cooling time 250 to 100°C /482 to 212°F 27 minutes
100 to 50°C /212 to 122°F 27 minutes
SYNC output (dry contact) Switching Voltage Maximum 30 VDC
Switching Current Maximum 100mA
Physical Specifications
Instrument Weight 10.8 kg / 23.8 lb
Size (L x W x H) 352 x 156 x 360 mm / 13.9 x 6.1 x 14.2 in
ATC-250B Specific Specifications
Accuracy with External STS Reference Sensor +0.07°C / +0.13°F
Transmitter supply Output voltage 24VDC +10%
Output current Maximum 25 mA
Transmitter input mA Range 0 to 24 mA
Accuracy (12 months) +0.01% Rdg. +0.015% F.S.
Voltage input VDC Range 0 to 12 VDC
Accuracy (12 months) +0.005% Rdg. +0.015% F.S.
Switch input
Switch dry contacts
Test voltage Maximum 5 VDC
Test current Maximum 2.5 mA
RTD reference input Type 4-wire RTD with true ohm measurements1)
F.S. (Full Scale) 350 ohm
Accuracy (12 months) ±0.001% rdg. + 0.002% F.S.

JOFRACAL Calibration Software

The JOFRACAL calibration software ensures easy calibration of RTD´s, thermocouples, transmitters, thermo-switches, pressure gauges and pressure switches.

JOFRACAL calibration software may also be used for manual calibrations, as it can be set up to accept manual entry of calibration data together with other liquid baths, ice points or dry-block heat sources. The calibration data collected may be stored on a PC for later recall or analysis. The ATC calibrator stores the calibration procedure and may be taken out to the process site without using a personal computer.

This then allows the Calibrator to:

  • Operate as a stand-alone instrument, using advanced calibration routines without the assistance of a personal computer on site;
  • Prevent unauthorized changes to a calibration routine. Personnel who are not authorized to alter a calibration routine cannot do so.

Calibration of up to 24 sensors with Ametek ASM

Using the Ametek ATC series together with the ASM Advanced Signal Multi-scanner offers a great time-saving automatic solution to calibrate multiple temperature sensors at the same time.

The ASM series is an eight channel scanner controlled by JOFRACAL software on a PC. Up to 3 ASM units can be stacked to calibrate up to 24 sensors at the same time. It can handle signals from 2-, 3- and 4 wire RTD’s, TC’s, transmitters, thermisters, temperature switches and voltage.
For more info on the ADM Advanced Signal Temperature Mulit-Scanner, please visit the 7533PC page.

Requirements Details
Minimum Requirements:
  • Intel Pentium II 1.4 GHz Processor
  • 64MB Ram (128MB recommended)
  • Standard VGA (800x600, 256 colors). 1024x768 Recommended
  • CD-Rom Drive for installation of program
  • 1 or 2 free RS-232 serial ports, depending on configurations
Minimum Requirements:
  • Microsoft Windows 98, Microsoft Windows NT 4.0, Microsoft Windows 2000
  • Microsoft Windows ME, Microsoft Windows XP, Windows Vista\
  • System fonts: MS Sans Serif, Arial
Calibration Software:  View PDF
Ordering Guide
Model Product Description
ATC-250 series, 28 to 250°C (82 to 482°F)
Code Model Version
Basic model no sensor-under-test or reference probe input
Including sensor-under-test or reference probe input
Code Mains Power Cable Type
European, 230V
UK, 240V
South Africa, 220V
Italy, 220V
Australia, 240V
Denmark, 230V
Switzerland, 220V
Israel, 230V
Code Insert Type and Size
1 x Insert for dry-block configuration
Liquid bath
Code Calibration Certificate
NPL Traceable temp. certificate(standard for Europe, Asia, Australia and Africa)
NIST traceable temperature certificate(standard for Americas)
Accredited certificate
Code Options
Carrying Case
Additional liquid kit, if dry-block configuration is ordered above
90° angled reference probe with accredited certificate (STS100A901AH
No option used
Sample Order Number
ATC250B230AM01FX - JOFRA ATC-250 B with standard accessories, 230VAC, European power cord, dry-block configuration with multi hole insert type M01, and NPL traceable temperature certificate.
Ordering Information
Model Description Buy Online Price
ATC250B Ametek ATC-250B Dry Block Calibrator Discontinued
See: RTC Series
Included Accessories
  • 1 -Either a kit for liquid bath use OR a kit for dry-block use
  • 1 -Test cables (2 x red, 2 x black)
  • 1 - Mains power cable
  • 1 - Traceable certificate
  • 1 -Traceable certificate - input performance
  • 1 - Insert
  • 1 - Tool for insertion tubes
  • 1 - RS-232 cable
  • 1 - JOFRACAL calibration software
  • 1 - AMETRIM-ATC Software to adjust the ATC series
  • 1 - Users’ manual (multi-language)
  • 1 - Reference manual (english)
Optional Accessories
Model Description Buy Online Price
105805 Ametek 105805 Case for ATC Series Dry Block  Buy Now $755.00