From Hanna Instruments , HI 24 is a new series of wall mounted, microprocessor-based EC and TDS controllers.
Thanks to the 4-ring probe and automatic temperature compensation feature, these meters can provide very accurate EC and TDS measurements. You can choose among models featuring ON/OFF or PID control, analogue input and output, double setpoint. The relay contacts can drive external devices as, for example, pumps or electrovalves. The input signal can come from a probe or a 4-20 mA transmitter. Models with RS485 output are also available. This option allows to insert the controller into a 2-wire RS485 network.
Each HI 24 model is provided with dual setpoint and is supplied complete with instructions.