ADInstruments Bio Amp, Owner'S Manual

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Chapter 1 Overview
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The PowerLab controls front-ends through an expansion connector called the
I
2
C (pronounced ‘eye-squared-sea’) bus. Each front-end added to the system
connects to the back of the previous front-end, in a simple daisy-chain
structure. This makes it easy to add front-ends to the system or to transfer
them between PowerLabs. In general, each front-end requires at least one
analog input channel of the PowerLab.
Front-ends are automatically recognized by the PowerLab system. Any front-
end feature such as gain or filtering is combined with the appropriate features
of the program and presented as a single set of software controls.
The Front-end
The Bio Amp is designed to allow the PowerLab system to perform isolated
measurements of biological signals — such as ECGs (EKGs), EMGs, and
EEGs — from humans or animals. All Bio Amps consist of electrically isolated
differential input AC amplifiers with common isolated ground connections.
The number of amplifiers corresponds to the number of Bio Amp channels.
For example, the Dual Bio Amp has two amplifiers with a shared ground
connector and input socket, and the Octal Bio Amp has eight differential
amplifiers with a shared ground connector and separate inputs. The Bio Amp
is not isolated by itself. For multiple biological recordings (more than two)
from a single subject it is recommended that you use a multi-channel Bio
Amp rather than “daisy-chaining” multiple Bio Amps.
The Front Panel
The front panel of a Bio Amp has a single input and an indicator light.
The front panel of a Dual Bio Amp has a single input, two indicator lights and
an audio output connector.
The front panel of the Octal Bio Amp has seventeen single-ended 1.5 mm
sockets consisting of eight red connectors, eight black connectors and a single
green connector. A stereo audio connector is shared between adjacent Bio
Amp inputs.
The Input Socket
Connections are made to the Bio Amp and Dual Bio Amp using the six-pin
socket on the front panel. The socket is physically and electrically isolated
from the low-voltage mains-supply circuitry of the PowerLab, and the input
connections are isolated internally, by isolation circuitry. The socket is of a
sort commonly used with ECG-type cables and leads, such as the Bio Amp