BARTINGTON INSTRUMENTS
Page 6 of 10 OM4550/1
5. Installation
The Mag900 & Mag901 is intended for integration into the customer’s own system. Bartington
Instruments cannot advise on the operation of third-party systems.
5.1. Unpacking
Safe handling precautions must be observed. The Mag900 and Mag901 fluxgates are wound with
thin copper wire. While these wires are covered with silicone coating and are recessed inside the
coil block, extra care must be taken not to break these delicate wires. Doing so will render the
magnetometer inoperable.
5.2. Orientation
Note: The direction of the geomagnetic field will vary with geographical location. It is
generally vertical at the poles, becoming horizontal at the equator.
5.3. Mounting
The Mag900 & Mag901 sensor assembly should be mounted in a stress-free manner using the
six mounting holes on the PCB. Dimensions and locations of the holes are shown in outline
drawing DR4576.
5.4. Cable Recommendations
The Mag900 & Mag901 provides differential output lines for analogue signal transmission.
The advantages of this differential arrangement are very high common-mode noise rejection and
the suitability of readily available cable types. Each of the two anti-phase output lines has low
output impedance at the signal source, damping the lines and preventing ringing.
The cable must be terminated with a differential amplifier having a circa 50kΩ input impedance,
due to cable inductance and capacitance considerations. This arrangement will provide some
damping to high frequencies but will attenuate the signals above the frequency range of the
sensor.
Note: Due to these effects:
• The cable pair loop resistance should not exceed 0.1 Ω per metre.
• The pair loop inductance should not exceed 0.5 micro-Henry per metre.
• The capacitance between should not exceed 52pF per metre.
• The capacitance between conductors and shield should not exceed 120pF per metre.
