HRA691 : Hardness Transmitter

Model : HRA691


Water Hardness Transmitter Without Display

HRA691 Water Hardness Transmitter is one easy to use wall mounting transmitter for continuous monitoring. Available without the LCD display, the transmitter can transmit the Hardness value of your solution with a very high accuracy with added option of self calibration. The Hardness of the water is indirectly calculated by the total number of dissolved minerals in the water. With Internal temperature compensation, HRA691 delivers fast and high accuracy. Precision Hardness transmitter immediately detects changes in the Concentration of the total amount of dissolved solids in the solution. With a 230V AC power supply, This instrument features 2 wire electrodes
making it easier in the world to facilitate the replacement of used electrodes.

  • Low Cost OEM Series.
  • Wide Temperature Range.
  • Precision Indication of Hardness with Current Output.
  • Compact Version.
  • Automatic Temperature Compensation.
  • Weatherproof / Fireproof ABS IP65 Enclosure.

Additional information

TDS Range

0 ~ 100% Hardness


±2% of F.S

Operating Temp.

-10 °C to 50 °C

Storage Temp.

-30 °C to 85 °C

Power Supply

230V AC

Electrode Connection

2 Wire Electrodes

Electrode Type



4-20 mA, 2 Wire


ABS Moulded Housing


Wall Mounting


Internal Span and Zero using Potentiometers