Product category:
Stepper and Servo Drives, Motors, Controls
News Release from: Micromech | Subject: Acc36UK sigma-delta board
Edited by the Engineeringtalk Editorial
Team on 23 October 2007
Instrument amplifier cancels noise
Together with three internal filters the Acc36UK has improved resolution, reduced noise when operating at 24 bits and will update all 16 channels to the dual RAM port.
Delta Tau has introduced the new Acc36UK sigma-delta board The analogue input device chosen was a AD8221 single-channel instrumentation amplifier
This article was originally published on Engineeringtalk on 26 Feb 2001 at 8.00am (UK)
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The system can cancel noise that appears on the differential inputs.
As a result only differential signals are amplified.
The AD7763 Sigma-Delta convertor from Analog Devices was selected for the analogue to digital convertor.
The output of the AD8221 is fed to the A/D convertor type AD7763.
This device is a 24bit convertor with 'in-built' gain and offset registers, as well as a series of low-pass filters.
These filters can be configured to optimise the output bandwidth relative to the input clock frequency, resulting in the maximum update frequency of 625kHz or 625ksample/s.
Depending on the number of filters implemented, other data rates can be achieved.
The data from all the channels is then synchronised and shifted serially into hardware registers on a microcontroller and thereafter into dual-ported RAM then onto the UBUS within the UMAC system.
The optically isolated clock from the microcontroller allows user-selectable update times.
Together with three internal filters the Acc36UK has improved resolution, reduced noise when operating at 24 bits and will update all 16 channels to the dual RAM port during PMAC's servo update time.
The design also includes eight hardware interrupts, enabling capture of data in real-time.
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