Analog DevicesEVAL-CN0326-PMDZ

Reference Design: Isolated Low Power pH Monitor with Temperature Compensation

EVAL-CN0326-PMDZ is a Pmod interface board with a completely isolated low power pH sensor signal conditioner and digitizer with automatic temperature compensation for high accuracy. The circuit gives 0.5% accurate readings for pH values from 0 to 14 with greater than 14-bits of noise-free code resolution and is suitable for a variety of industrial applications such as chemical, food processing, water, and wastewater analysis. This circuit supports a wide variety of pH sensors that have very high internal resistance that can range from 1 MΩ to several GΩ, and digital signal and power isolation provides immunity to noise and transient voltages often encountered in harsh industrial environments.

Block Diagram: 

 

Features:

• 0.5% Accuracy

• Low power

• Temperature compensation

• Completely isolated

Applications:

• Healthcare

  • Life sciences & medical instrumentation

• Instrumentation & measurement

  • Chemical analysis & analytical instruments

• Building technology

  • Building control and automation

Functional Test Setup

The following equipment is needed:

• A PC with a USB port and Windows® XP and Windows® Vista (32-bit), or Windows® 7 (32-bit)

• EVAL-CN0326-PMDZ circuit evaluation board

• EVAL-SDP-CB1Z circuit evaluation board

• SDP-PMD-IB1Z SDP interposer board

• CN0326 Evaluation Software

• Power supply: 6 V wall wart or equivalent

• Yokogawa 2000 Precision DC Power Supply or equivalent

Compatible Boards:

• EVAL-SDP-CB1Z: Blackfin® (SDP-B) controller board

• SDP-PMD-IB1Z: Pmod to SDP Adaptor Board

• Intel boards with the Pmod connector

Related ADI parts:

• AD8603: Micropower RRIO Low Noise Precision Single CMOS Op Amp

• AD7793: 3-Channel, Low Noise, Low Power, 24-Bit Sigma Delta ADC with On-Chip In-Amp and Reference

• ADUM5401: Quad-Channel Isolators with Integrated DC/DC Converter (3/1 channel directionality)

Reference Documentation:

• ADI Pmod Daughter Cards