1294A Impedance Interface System

System Overview

Electrical impedance is a well-proven, powerful technique for analyzing the physical and chemical properties of a wide range of materials (see Applications).

Historically, use of the technique with high impedance, low loss materials was limited by a number of factors, such as the ability to measure accurately the very low currents involved, particularly when high electrode impedances are present (for example In-Vivo measurements). The 1294A Impedance Interface has been designed specifically to overcome these difficulties, and to meet the present and future needs of materials analysts everywhere.

Used in conjunction with Solartron’s 1260A or 1255A Frequency Response Analyzers, the 1294A’s advanced measurement technology offers:

Improved accuracy:
  • True differential 4-terminal connections minimize the effects of localized disturbances at the current injection points
  • Balanced generator
  • Driven shields
Wide measurement range:
  • 1 μV, 1 pA sensitivity
  • Impedance range 10 mΩ to >1 GΩ to cover a wide range of materials
  • Up to 750 kHz frequency range
Temperature control:
  • 1294A system interfaces with standard temperature controllers, cryostats and furnaces
Safety compliant:
  • IEC 601 connections - for In-Vivo investigations into a wide range of applications including cosmetics, skin hydration, tissue impedance and tooth decay.

Civil Engineering: Biomaterials:
Cement paste research Ischemia and tumor research
Content/strength of concrete mixes Tooth decay
Dermatological studies
Research in fruit and plants
Adhesives: Ceramics/Composites:
Epoxy resin curing Gas sensors
Thermoset polymers Gas separation membranes

Impedance measurement
All materials are able to pass current when a voltage is applied.  If a variable (AC) voltage is applied to the material, the ratio of voltage to current (V/I) is known as the impedance. In many materials the impedance varies with the frequency of the applied voltage, in a way that is related to the physical structure of the material, to chemical processes within it, or to a combination of both.

Accurate measurement of the impedance of materials, by applying a low level signal over a wide frequency range, can yield valuable information about the properties of the material. For example, measuring the impedance of a sample of organic tissue - anything from a piece of fruit to a human kidney - can reveal its condition and suitability for storage, freezing or transplant. Samples of concrete or cement can be analyzed to predict strength, or water/cement/binder mix, and complex curing cycles for composite structures such as aircraft wings can be monitored and controlled.

Impedance is
  • Non-invasive: impedance can often be measured with surface electrodes.
  • Non-destructive: low level stimuli required typically have no (or minimal) effect on material being investigated.
  • Repeatable: many impedance tests compare the state of a material over a period of time, or under varying conditions, e.g. adhesive curing. Consistent measurements are essential for a true indication of these change
  • Documents +

  • Specifications +

    PC Control Connections
    to 1294A Parallel interface
    to FRA: IEEE488 interface
    1294A measurement Connections
    to FRA: Gen, V1 Hi, V1 Lo, V2 Hi
    to sample:

    4-terminal connections
    4-terminal connections

    Generator Output

    Voltage Mode Normal connections IEC601 connections
    Max. DC voltage ±10 V ±10 V*
    Max. AC voltage 7 V rms 7 V rms*
    Max. AC + DC ±10V peak ±10 V peak*
    Current Mode Normal connections IEC601 connections
    Transconductance 10 mA/V 10 mA/V*
    Max. DC current ±45 mA ±10 µA*
    Max. AC current 30 mA rms 10 mA rms*
    Max. AC + DC ±45 mA peak ±14 mA peak*
    * subject to IEC601 current limits. Balanced generator capability in voltage mode only.

    Generator input (from FRA Gen connector)
    Rear connection
    single BNC
    Max. input voltage 10 V peak from 50 Ω source
    Switchable attenuator x1 / x0.01
    Switchable gain x1 / x2
    Input impedance 50 Ω for x1, 25 kΩ for x2
    Voltage buffers
    Driven shield connections to sample
    Amplifier gain x1
    Common mode range ±10 V
    Bias current 1 nA max
    Input resistance, to ground
    >1 GΩ
    Input capacitance
    10 pF to ground
    Input capacitance 1 pF (differential)
    Voltage buffer output (to FRA V1Hi & V1Lo)
    Rear connections two BNCs
    Maximum output ±10 Vpeak
    Output resistance 50 Ω

    Current to voltage converter
    Rear panel Selector Current Range Resolution FRA Range Range Resistor
    1 V/100 mA 30 mA 1µA 300 mV 10 Ω
    1 V/100 mA 3 mA 100 nA 30 mV 10 Ω
    1 V/10 mA 300 µA 10 nA 30 mV 100 Ω
    1 V/1 mA 30 µA 1 nA 30 mV 1 kΩ
    1 V/100 µA 3 µA 100 pA 30 mV 10 kΩ
    1 V/10 µA 300 nA 10 pA 30 mV 100 kΩ
    1 V/1 µA 30 nA 1 pA 30 mV 1 MΩ

    Current to Voltage converter output (to FRA V2 Hi)
    Rear connection single BNC
    Maximum output 300 mV rms
    Output resistance 50 Ω
    SMaRT PC Software
    Provides control of  FRA, 1294A and optional temperature controller
    Result parameters Z*, Y*, E*, M*, C*
    Result formats real, imaginary, magnitude, phase, tanδ
    plotted vs: frequency, time, temperature, bias, AC level
    plotted on: Bode, complex plane
    Power supply 90 VAC to 264 VAC, (47 Hz to 440 Hz)
    Power consumption 18 W
    Weight 14.5 lb (6.5 kg)
    Operating temperature 5 ºC to 40 ºC (40 ºF to 104 ºF)
    General safety EN61010
    Medical safety IEC601, EN60601-1 (Power supply: 47 to 65 Hz)
    Medical Safety Passive circuits in the drive and sense lines of the IEC601
    connections protect live subjects from excess current in
    accordance with the IEC601 standard.

    1294A Typical measurement accuracy

    System Requirements
    Frequency Response Analyzer 1260A, 1255A, 1250E or 1253A
    Minimum PC requirements

    Microsoft Windows ™ 10, 7, XP

    USB Port (for USB-GPIB NI Adapter)
    PCI Express slot or Parallel Printer Port (for control of 1294A)

    IEEE488 National Instruments USB-GPIB Adapter

    Temperature controller:

    Oxford Instruments ITC503, Lakeshore 340, Eurotherm 2000 Series

  • Accessories +

    • 129620A High Temperature Test System

      • Room temperature to 1200ºC
      • For testing solid oxide, solid electrolyte, super ionic conductors
      • Dual gas design for SOFC
      • Split tube furnace for easy sample load

      Keep Reading

    • 129610A LHe/LN2 Cryostat System

      • Cryogen not in contact with sample - prevents sample damage
      • Low cryogen usage (low running cost) - capillary tube around sample space
      • 5 K to 600 K (compatible with liquid helium and liquid nitrogen)
      • Custom sample holder for compatible with solid, powder or liquid samples

      Keep Reading

    • 12962A Room Temperature Sample Holders

      • Room temperature to 1200ºC
      • For testing solid oxide, solid electrolyte, super ionic conductors
      • Dual gas design for SOFC
      • Split tube furnace for easy sample load

      Keep Reading

  • Software +

    • SMaRT Impedance Measurement Software

      • Wide range of materials test AC techniques (impedance, capacitance, admittance, permittivity and Mott-Schottky) for all types of materials including dielectrics, insulators and electronic materials
      • Full support of 12xx materials test products including 1260A Impedance Analyzer and 1296A Dielectric Interface
      • Integrated temperature control including custom designed cryostats and furnaces

      Keep Reading

    • ZPlot Software

      • Wide range of potentiostatic and galvanostatic electrochemical techniques, including cyclic voltammetry, galvanic pulse, impedance, AC voltammetry and Mott-Schottky
      • Full support of 12xx series Impedance and Frequency Response Analyzers including 1260A, 1255B, 1252A, 1250E, 1253A
      • Full support of Power Boosters up to 100 V and 100 A for DC and EIS testing of high power batteries/ fuel cells and for anodization and electroplating

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    • ZView Software

      • ZView is the companion EIS data analysis software for ZPlot
      • Multiple display formats (impedance, admittance, capacitance, permittivity and electrical modulus)
      • Comprehensive data analysis capabilities include an extensive library of equivalent circuit data fit models – R, C, L, Warburg, Distributed Elements

      Keep Reading