A30 Hydroponics ORP pH Controller

The Apure A30 is an online pH/ORP controller for use with a compatible electrode and temperature element. For hydroponic nutrient solutions, select the appropriate pH or ORP measurement configuration and confirm the probe, outputs and installation requirements.

Measurement and electrode selection

A pH electrode measures an electrical potential related to hydrogen-ion activity relative to a reference system. An ORP electrode measures oxidation-reduction potential in mV. Select the electrode type, reference system and temperature element specified for the controller configuration.

Match the sensor’s wetted materials, reference system, process connection, temperature and pressure limits to the actual liquid. The controller’s temperature indication or compensation range is separate from the operating limits of the electrode, cable and mounting assembly.

Outputs and commissioning

A 4–20 mA output is an analogue current signal for a compatible analogue input or data-acquisition device. RS485 communication requires a supported interface, matching serial settings and the supplied protocol/register map. An RS485 communication port on a controller does not by itself establish compatibility with a digital RS485 probe.

Before commissioning, select the measurement mode and current-output scaling, use the buffer family or ORP verification solution specified by the instrument instructions, and verify readings and control settings before connecting the process-control equipment. Obtain the ORP mV range, resolution and error specification for the supplied ORP version when ordering.

Before panel machining, obtain the outline, panel cut-out and installation-clearance drawing for the supplied A30 configuration and check it against the actual instrument. Use its own terminal diagram for wiring.

pH and ORP readings serve different monitoring tasks. Nutrient conductivity and individual nutrient concentrations require their own measurements; they are not determined by a pH or ORP reading alone.