K800 Amplifier

The K800 Amplifier provides a user-friendly method of connecting both Biometrics Ltd sensors and 3^rd party sensors to your own data acquisition system, video motion capture system, or other instrumentation.

Although the K800 functions as a general DC amplifier, the hardware is primarily digital circuity, giving a design with the greatest accuracy, negligible drift, and greatest immunity to noise. Multiple Amplifiers may simultaneously be used to collect as many channels as required.

The K800 Amplifier is a precision amplifier designed to provide the researcher with complete ease of use.

Easy to use general purpose precision amplifier
8 analog channels
5 digital channels
+5V built in power supply

Accepts all Biometrics Ltd sensors
Accepts other sensors including load cells
Real time display for all channels in engineering units
RS422 digital data transfer from Subject Unit to Base Unit

Specifications

Dimensions	Subject Unit: 100 x 50 x 25 mm Base Unit: 180 x 170 x 48 mm	Mass	Subject Unit: 150g Base Unit: 550g
Analogue Channels	8	Digital Channels	5
Communication from Subject Unit to Base Unit	RS422	Input Voltage Differential Bridge Mode	± 12mV
Input Voltage Single Ended High Level Mode	± 4mV	Output (Full Scale)	Analog +0.0 to +4.0 V
Analog Channel Input Impedance	1M Ohm	Power Supply Per Channel	+ 5.0 V dc
Power Supply Per Channel Tolerance	± 1 %	Accuracy	Better than ± 0.5 % full scale
Maximum Common Node	+3.5 V to -2.5 V	Bandwidth General	500 Hz

Any combination of sensors may be connected to the small Subject Unit which is connected using a 6m cable to the larger Base Unit. All Biometrics Ltd sensors are easily connected with the analogue output voltages standardized in the range +0 to +4 Vdc. The LCD and 2 button switches act as the interface to configure the individual channels for the type of sensor attached. This enables any combination of sensors to be attached. The analogue output is via a single cable (R2000i) with flying wires allowing interface to a wide range of analogue data recording systems.

The sensors are categorised into 2 groups:

Differential output bridge type sensors including Biometrics' Goniometers, Torsiometers, Hand Dynamometer, Pinchmeter
Single ended high level sensors including Biometrics' sEMG pre amplifier, 3 axis accelerometer

Examples of other differential type sensors include strain gauge based devices such as load cells and certain flow meters. A differential bridge type sensor may be connected providing it can be powered by +5 Vdc and the output is in the range of +/- 12 mV. Examples of other single ended high level sensors include potentiometers. A single ended high level sensor may be connected providing it can be powered by +5 Vdc and the output is in the range of +/- 4 V. For all 8 analog channels the K800 recognizes automatically whether a differential bridge type sensor or single ended high level sensor is connected. The K800 also has 5 digital channel inputs which are used for contact switches and event markers.

Event Marker IS3

A 1.8 metre cable with a suitable connector at one end to connect to the K800 Subject Unit, and a hand held switch on the other. This useful accessory allows time marks to be added to the data and enables the operator to highlight specific events during data collection.

Contact Switch Assembly FS4

An assembly of 4 Force Sensing Resistor Sensors (FSRs) each on 1.2 meters of cable which are readily connected to the Amplifier via one connector for use as switches to indicate contact e.g. heel and toe strike or palmer contact. The sensors are thin and robust and are usually placed inside the subject’s shoe or glove for convenience.

Analog Output Cable with BNC Connectors R2000iBNC

The optional cable R2000iBNC has 8 BNC connectors for connection to a range of proprietary AD boards. This allows realtime analog data transfer of up to 8 channels per Amplifier unit directly into other hardware for synchronization with other inputs - for example integrating surface EMG measurements collected by the Amplifier into video motion capture systems.