Bartington MAG-03PSU, Operation & Maintenance Manual

Page: 6 / 21

OM0065 ISSUE 5 PAGE 6 of 21
8 BATTERY CHARGING
A 12 V dc (nominal unregulated) output mains adaptor for battery charging purposes is supplied
as an accessory. Before use ensure that this is of the appropriate voltage for the local mains
supply, either 110 V or 220 V/240 V ac, 60 Hz or 50 Hz. As an alternative the batteries may be
charged from a vehicle dashboard 12 V connector.
The internal battery will be completely charged in around five hours when connected to the
charger via the 2.1 mm socket marked "CHARGER", but may be left on charge indefinitely.
Charging will occur regardless of the position of the on/off switch. It is not necessary to
disconnect the charger when not in use.
9 LOW BATTERY ALARM
The fully sealed lead acid rechargeable battery within the power supply will provide many years of
use if regularly charged. However, should this type of battery ever become completely discharged
for an extended period of time its capacity will be severely reduced. For this reason a low battery
alarm is incorporated in the unit. Should the batteries reach a low state of charge, with the power
supply on, an audible alarm will be heard to sound continuously in which case the battery should
be recharged immediately.
The low battery alarm will sound for a short time when the power supply is switched on to
confirm that power is available and that the alarm operates. If the alarm fails to sound at switch
on then the battery may be completely discharged.
10 ANALOG OUTPUT
The analog output should not be loaded by an impedance of less than 10 k
Ω
or 200 pF.
Connection should be via BNC coaxial cables of not more than 2 metres length. If the analog
outputs are to be connected to a differential input then ensure that the common mode range of the
input is constrained to within a few volts of the system ground to which the magnetic field sensor
is to be connected. This may usually be done by establishing a connection between the output
LOW or BNC outer connection and the system ground.
11 TAKING MEASUREMENTS
11.1 CONNECTING UP
Connection between the magnetic field sensor and the power supply should not be made or
broken with the power supply switched on as this could cause damage to the magnetic field
sensor.
11.2 FILTER SELECTION
The power supply contains a filter section for each channel. The low pass filter is always
connected to remove unwanted high frequency components from the signal and the high pass can