อุปกรณ์วัด Control System (Industrial Grade EC Controller with Proportional Fertilizer Dosing for Hydroponics Applications)

HI 9931

Industrial Grade EC Controller with Proportional Fertilizer Dosing for Hydroponics Applications

HI 9931 is a wall mounted meter that measures and controls conductivity in the 0 to 10 mS/cm range. A single set point allows for proportional dosage of fertilizer solutions. The proportional settings can be fine tuned through two conveniently positioned dials on the front panel. The time cycle is adjustable from 0 to 90 seconds and the proportional band from 0 to 1.6 mS/cm. Calibration and set points have a coarse and fine tuning trimmers. A pump or electrovalve can be wired directly to the controller and be powered through the terminals.

HI 9931 also provides for an alarm relay which is activated when the measurements exceed the set point by a user selectable margin from 0.5 to 2.5 mS/cm. The alarm also triggers if, due to a malfunction, the continuous dosing time exceeds the operator adjustable period of 1 to 10 minutes. The alarm can be configured in either normally closed or open position and turned off during maintenance. HI 9931 also provides an isolated output signal which is user selectable between 0-20 or 4-20 mA.

HANNA four-ring conductivity probes ending in a DIN connector can be quickly attached to the HI 9931. Readings are automatically compensated for the effects of temperature in the 0 to 50°C (32 to 122°F) range. For quick and easy wiring, HI 9931 comes with extractable terminal modules. Several LED’s show whether the set point or alarm relays have been activated.

Specifications

Range  0.00 to 10.00 mS/cm
Resolution  0.01 mS/cm
Accuracy @ 20°C  ±2% f.s.
Calibration  through “ZERO CAL” and “SLOPE CAL” trimmers
Setpoint  from 0 to 10.00 mS/cm
Temperature
Compensation  automatic, 0 to 50°C (32 to 122°F) with ß = 2%/°C
Recorder Output  selectable at 0-20 mA or 4-20 mA (isolated)
Proportional
Control  conductivity from 0.0 to 1.6 mS/cm and time cycle from 0 to 90 seconds
Alarm Contact  terminal can be configured as normally open or normally closed (isolated output max. 2A, max. 240V, resistive load, 1,000,000 strokes). The alarm is activated if conductivity exceeds by more than the user selectable interval (0 to 2.0 mS/cm) from the set point or due to overdosage
Dosing Terminals  relay (115 to 240V, max.2A, 1,000,000 strokes) is activated whenever conductivity falls below the set point
Probe  four-ring potentiometric with built-in temperature sensor and DIN connector (not included)
Power Supply  ±10% 115 VAC or 230 VAC; 50/60 Hz
Environment  -10 to 50°C (14 to 122°F); RH max 95% non-condensing
Case Material  fiber-reinforced, self-extinguishing ABS
Dimensions  221 x 181 x 86 mm (8.7 x 7.1 x 3.4’’)
Weight  1.6 kg (3.5 lb.)

Accessories

Solutions
HI 7031L  1413 µS/cm EC Solution, 500 mL Bottle
HI 7039L  5000 µS/cm EC Solution, 500 mL Bottle
Probes
HI 3001D  Flow-thru Conductivity Probe with DIN Connection and 3 m cable