High Temperature Clip-On Gages (700 °C) – Model 7641

Model : 7641

Applied Standard

  • These COD gages use a high-temperature capacitive sensor and do not require any cooling. They will operate up to the maximum temperature limit of most environmental chambers used in materials testing. 
  • The Model 7641 is ideal for determination of fracture mechanics parameters such as JIC, KIC, R-curve, fatigue crack growth rate (da/dN), and testing to standards such as E1820, E399, E647, etc. All units can be displaced slightly in compression for ease of installation.
  • The COD gage is supplied with the advanced DT6229 controller. The standard output is 0-10VDC analog signal, factory calibrated with the COD gage. This system provides a number of functional enhancements, including: high speed digital output, built in calibration and tare functions, analog and digital filters, and more. 
  • The 7641 is readily interfaced with most existing test controllers, and may be directly connected to a data acquisition system or chart recorder, or directly to a PC. The 7641 may be used for strain controlled tests such as JIC.


  • May be left on through specimen failure.
  • Improved performance at high temperature.
  • Improved noise rejection, resolution, and accuracy.
  • Improved clearance with most clevis designs. 
  • Improved linearity and reduced stiffness.
  • Reduced size and weight, and improved high frequency performance.
  • All standard models are suitable for cyclic testing.
    - >25 Hz is typical for 10mm GL and larger, up to 100 Hz for some configurations
    - Typically limited by the user’s test apparatus, software settings, and filter selection
  • Digital controller and power supply included. Provides high level DC voltage output with low noise. Easily interfaced to test controllers, data acquisition boards and chart recorders.
    - Includes high speed analog and digital outputs
    - Intuitive web-based user interface for setup, calibration, and data acquisition
    - Built-in calibration reference and auto-zero features
    - Multiple extensometer calibration files may be loaded for use with one controller
    - Multiple temperature-specific calibrations may be stored
    - Selectable analog and digital filter options from 2 Hz to 3 kHz
  • Ships fully calibrated with electronics (traceable to NPL (UK)) with user specified voltage output.
  • Mechanical over-travel protection.
  • All standard units meet ASTM E1820, ASTM E399, ISO 12135, and ISO 9513 Class 1 requirements for accuracy. A test certificate for ASTM E1820 is included. ASTM E399 or ISO 12135 test certificates are available upon request.
  • Durable stainless steel knife edges.
  • Includes high quality foam lined case.
  • Rugged, dual flexure design for strength and improved performance. The next-generation design enables cyclic testing at much higher frequencies

Load frame

  • Connectors to interface to nearly any brand test equipment
  • Bulkhead adapters for vacuum chambers
  • Bolt on knife edges for attachment to test specimens without machined attachment points


  • Analog Output: User specified, +/-5 VDC or +/-10VDC typical, ±10.8VDC rail
  • Digital Output: 24 bit high speed Ethernet output with built-in web interface
  • Linearity: 11 point linearization, ≤0.1% FS typical linearity
  • Resolution: <55 PPM (0.006%FS) RMS@4 kHz, <6 PPM (0.0006%FS)@100 Hz
  • Cyclic Testing: >25 Hz typical@10mm GL, >10 Hz@5mm GL
  • Analog Filter: Selectable 100 Hz analog and 2 Hz - 3 kHz digital filters
  • Temperature Range: Ambient to 700℃(1300°F). Use up to 800℃ is possible – contact Epsilon for details. Springs may require periodic adjustment or replacement after long-term testing above ~600℃.
  • Temperature Sensitivity (Gain): <100 PPM/℃(0.01%FS/℃) typical
  • Temperature Sensitivity (Offset): 20 PPM/℃(0.002%FS/℃) typical
  • Sensor Cable: 0.7 m (2.5 ft ) tri-axial high temperature cable, plus 1.5 m (5 ft) room temperature extension cable
  • Operating Force: 1-5 kg typical, depending on model
  • Environment: Recommended for elevated temperature testing in dry air, inert / non-corrosive gases, or vacuum
  • Power: Includes power supply for your country (specify)