Owner’s Guide
5
Earthing and Ground Loop Noise
The prime function of earthing is safety, that is, protection against fatal electrocution.
Safety concerns should always override concerns about signal quality. Secondary
functions of earthing are to provide a reference potential for the electrical equipment
and to mitigate against interference.
The earthing (grounding) stud provided on the back panel of the PowerLab is a
potential equalization post and is compatible with the DIN 42801 standard. It is directly
connected to the earth pin of the power socket and the PowerLab chassis. The earthing
stud can be used where other electronic equipment is connected to the PowerLab, and
where conductive shields are used to reduce radiative electrical pick-up. Connection to
the stud provides a common earth for all linked devices and shields, to reduce ground-
loops.
The earthing stud can also be used where a suitable ground connection is not provided
with the mains supply by connecting the stud to an earthed metal infrastructure,
such as a metal stake driven into the ground, or metal water piping. This may also be
required in laboratories where safety standards require additional grounding protection
when equipment is connected to human subjects. Always observe the relevant safety
standards and instructions.
Note that electromagnetically-induced interference in the recorded signal can be
reduced by minimizing the loop area of signal cables, for example by twisting them
together, or by moving power supplies away from sensitive equipment to reduce the
inductive pick-up of mains frequency fields. Please consult a good text for further
discussion of noise reduction.
Cleaning and Sterilization
ADInstruments products may be wiped down with a lint free cloth moistened with
industrial methylated spirit. Refer to the manufacturer’s guidelines or the Data
Card supplied with transducers and accessories for specific cleaning and sterilizing
instructions.
Inspection and Maintenance
PowerLab systems and ADInstruments front-ends are all maintenance-free and do
not require periodic calibration or adjustment to ensure safe operation. Internal
diagnostic soft ware performs system checks during power up and will report errors if a
significant problem is found. There is no need to open the instrument for inspection or
maintenance, and doing so within the warranty period will void the warranty.
Your PowerLab system can be periodically checked for basic safety by using an
appropriate safety testing device. Tests such as earth leakage, earth bond, insulation
resistance, subject leakage and auxiliary currents and power cable integrity can all be
performed on the PowerLab system without having to remove the covers. Follow the
instructions for the testing device if performing such tests. If the PowerLab system is
found not to comply with such testing you should contact your PowerLab representative
to arrange for the equipment to be checked and serviced.
Summary of Contents for BIO
Page 1: ...Owner s Guide BIO AND NEURO AMPLIFIERS ...
Page 18: ...Owner s Guide 16 ...
