WRSGC Standards & Technical Information


SUGGESTED INDUSTRY STANDARD for Strain Gage Bridge Designation & Color Code

Technical Committee on Strain gages – Society for Experimental Stress Analysis

Adopted 9/18/57, Revised 1/4/77, Revised 9/28/77, Corrected 9/29/77

WRSGC Strain Gage Bridge Standard

  1. Wherever possible, tension, elongation, increased pressure, acceleration, or other generally accepted positive quantities shall produce positive output signals as indicated.
  2. The bridge elements shall be arranged so that functions producing positive output will cause increasing resistance in arms 1 and/or 3 and decreasing resistance in arms 2 and/or 4 of the bridge.
  3. The auxiliary wiring for 6 or 8 wire system will have same color but as a tracer on white wire or IMSA colors.
  4. Quarter Bridge – when only one bridge element is active use arm No. 1 (arms 2, 3, and 4 as dummy elements).
  5. Half bridge – when a tension and compression component is to be measured use arms nol 1 and no.2 (arms 3 and 4 as dummy elements).
  6. The direction or position of the function producing a positive output signal shall be indicated on transducers. Shunt calibration resistor shown will produce a positive output signal. The following markings are suggested.
    • + Tension load cells, universal load cells, micrometers, etc.
    • – Compression load cells
    • + Accelerometers and flow meters
    • + Torque transducers
    • + Differential pressure cells at the port where the higher pressure causes positive output signals.
  7. For shielded type bridge systems pins 5/E, 7/G, and 9/I shall be shielded terminals for 4, 6 and 8 wire systems.

WRSGC Strain Gage Bridge Standard – Quarter Bridge
Adopted 9/17/80, Revised 3/4/81

  1. Wherever possible, tension, elongation, increased pressure, acceleration, or other generally accepted positive quantities shall produce positive output signals as indicated.
  2. The bridge elements shall be arranged so that functions producing positive output will cause increasing resistance in arms 1 and/or 3 and decreasing resistance in arms 2 and/or 4 of the bridge.
  3. The auxiliary wiring for 6 or 8 wire system will have same color but as a tracer on white wire or IMSA colors.
  4. Quarter Bridge – when only one bridge element is active use arm No. 1 (arms 2, 3, and 4 as dummy elements).
  5. The direction or position of the function producing a positive output signal shall be indicated on transducers.
    • + Tension load cells, universal load cells, micrometers, etc.
    • – Compression load cells
    • + Accelerometers and flow meters
    • + Torque transducers
    • + Differential pressure cells at the port where the higher pressure causes positive output signals.
  6. For shielded type bridge systems pins 5/E, 7/G, and 9/I shall be shielded terminals for 4, 6 and 8 wire system

    WESTERN REGIONAL STRAIN GAGE COMMITTEE
    Guideline for a Multiconductor Strain gage Cable

    A need exists for low millivolt signal levels to be transmitted by better quality multiple conductor cables of considerable length.

    CONDUCTORS:

    Three through eight twisted, stranded conductors of tinned copper per ASTM-B-174, AWG 20-16/32, or AWG 18-16/32

    COLOR CODE:

    Jacket: orange, grey, white, or black.

    Conductors: Per ISA-S37.3, ANSI-MC6.2-1975, and WRSGC/SESA 5-6-1960

    INSULATION:

    Superior to the PVC materials currently in use. The dielectric material should be nonhygroscopic and approach zero water absorption and zero water permeability. Target jacket thickness of 0.016 in. or less and conductor insulation of 0.012 in. or less. Target resistance values should be constant as practical humid and wet environments and as high as possible (target value of 500 megohms per 1,000 feet). The breakdown level of the dielectric materials shall be greater than 150 volts D. C.

    CONSTRUCTION:

    The cable shield shall be aluminized polyester tape with 100% coverage of all conductors. A 22-AWG drain wire shall be intimate contact with the shield throughout the entire cable length. The cable shall have as small a diameter as practical and flexible enough to have a bend radius less than six (6) cable diameters. Overall cable strength sufficiently high to be pulled through conduits.

    TEMPERATURE:

    Range: -40 Deg. C to 135 Deg. C

    Tolerance: Withstand “shrink-fit” sleeving temperatures for about three minutes without melting.

    CAPACITANCE:

    As low as practical.

    OPTIONS:

    Options as follows:

    1. Pass the IEEE Flame Test.
    2. Non-hosing, bolcked, standard 50, 200, 500, or 1,000-psi Test.
    3. Cable jacket reinforcement.
    4. O/C Inspected, guaranteed by the manufacaturer.
    5. High strength copper conductors.
    6. AWG cable range 16 through 28.
    7. Double shielded cables.
    8. Magnetic shielding.
    9. Antimicrophonic treatment