RA-1100 Residual Chlorine Analyzer

The Eagle Microsystems Model RA1100 Premier Series Residual Chlorine Analyzer is an amperometric instrument designed to continuously analyze the residual concentration of free or total chlorine, chlorine dioxide or potassium permanganate in water or wastewater.

A sample of water or wastewater containing the target chemical is pumped to a reservoir in the instrument where it is fed by gravity to the amperometric measuring cell. A pH buffering agent is also injected into the cell using a peristaltic pump. A small current is developed within the cell, the level of which is directly proportional to the concentration of the target chemical within the sample.

The output of the cell is processed by an on-board microprocessor-based digital controller and the residual value is displayed on the LCD readout of the instrument. The digital controller transmits a 4-20 mAdc signal for recording or remote display and is capable of outputting a signal for residual process control via one of several modes including: flow pacing and compound loop control.

The dissimilar metal electrodes are continuously cleaned by PVC spheres which are stirred within the cell by a motor driven striker. This continuous cleaning eliminates signal drift and minimizes the need for recalibration of the instrument. Temperature compensation of the cell output is provided by a thermistor which senses cell temperature.

All control and calibration functions are digital and adjustments are made via the simple, user friendly, 4-pushbutton keypad on the face of the instrument. The controller display is a 2-line by 16-character backlit LCD. All operations and calibration adjustments are menu driven through this display.


  • Proprietary AutoZero function
  • All-digital control
  • Continuous electrode cleaning
  • Eight standard field selectable ranges
  • Measurement of free or total chlorine residual
  • Full automatic control capability
  • Pushbutton control of all functions

Typical Applications

  • Liquified gas cylinders such as chlorine, sulfur dioxide and carbon dioxide
  • Carboys and small drums (up to 30 gallon)

Download a PDF Data Sheet