Kaman KD-2306 - Manual (Page 16)

Kaman Precision Products PART NO: 860512-001
www.kamansensors.com Last Revised: 8/3/2009
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6.2 Bridge Card
The KD-2306 control module is stocked in only two basic versions, with a 500 KHz oscillator, and with
a 1 MHz oscillator. Unique circuitry to accommodate different sensors, cable lengths, and target
material (as necessary), is added to the control module in the form of a plug in circuit card. This small
circuit card is called a “bridge card”. Some generalizations concerning the bridge card are:
1. Different bridge cards are required for ferrous and non-ferrous target materials for small
sensors (.5SU, .5SUM, 2U, 1U1, 1S/1SM, 1SU/1SUM, and 1UEP).
2. For sensors 2S and larger, a different bridge card is generally not required if target material is
changed. Changing target materials requires only system recalibration to the new material.
3. The bridge card must be matched to the operating frequency of the control module, sensor
type, and sensor cable length.
The bridge card may be replaced as follows. Normal Electrostatic Discharge (ESD) procedures must
be followed.
1. Remove the base of the DIN enclosure with a small screwdriver.
2. Remove the Twin BNC (TBNC) connector retaining nut.
3. Slide the circuit cards out of the DIN enclosure by applying constant pressure on the TBNC
connector.
4. Separate the circuit cards and remove the bridge card from its socket. Insert the replacement
bridge card making certain to align the ground pin to the top of the circuit card.
5. Reattach the circuit cards together, reinsert them into the DIN enclosure. Replace the
enclosure base and TBNC connector retaining nut.
The system (sensor and control module) must be recalibrated prior to use to ensure accurate
measurements.
6.3 Target Material
Each system is individually set up and calibrated at the factory for a specific material. Changing the
target material from the material used for calibration will affect system performance. This is due to
different electrical conductivities and ferro-magnetic properties of conductive materials. When target
material is changed, a calibration adjustment at a minimum is recommended. Reference guidelines
in section 6.2 for additional system changes that may be required.
6.4 Sensor Cable Length
The sensor cable is part of the inductive bridge circuit. As such, any changes to the cable can affect
system calibration and performance. Some guidelines about modifications to the cable are:
1. Addition of feed through connectors generally does not affect system performance.
2. Small changes to cable length usually require only system recalibration.
3. Changes of cable length of 5 feet or more usually require replacement of the bridge module.