iGrow 1800 Installation Guide
Page26
Link4 (714) 524-0004
Light Sensor
Link4 offers two types of light sensors; Solar and Quantum. The Solar Light Sensor is sensitive to the
visible light spectrum, whereas the Quantum version limits the light measurement to the 400 to 700
nanometer band where photosynthesis takes place (PAR). Whichever type you’ve chosen, the
installation only varies slightly.
1. Open up the front panel to the 90 deg. position, as shown in Figure 4.5. Make sure the cable
supports the front panel securely.
2. Find a location that is open and free from obstructions for the sensor to be expose to light from all
necessary angles.
3. Run the free end of the sensor cable to the controller unit.
4. You may extend the sensor cable as needed, but make sure to use an adapter and wire approved by
Link4 to make any extensions (the wire and adapter can be purchased from Link4).
5. Carefully insert the cable through the right most watertight fittings at the bottom of the enclosure. It is
easy to strip insulation and/or break wires when pulling cable. If you want to bundle wires tighter, use
UV protected “tie wraps” (typically blue or black), and do not over-tighten.
Note:
If any splices are needed to extend cable length, make certain they are WATERTIGHT. Water or
fertilizer infiltration WILL cause unstable sensor readings.
6. Keep sensor cables away from interference sources, including high voltage power wiring, inverters,
motor controllers, mercury arc, or sodium lamp circuits. Placing sensor cable near such wiring may
cause erratic sensor readings.
a. Connect the wires as shown in Figure 4.14a for Solar, and Figure 4.14b for Quantum light
Sensor.
7. After installing the sensor, it is recommended that sensors be checked by plugging in the power
supply and testing under various conditions before moving on in order to make sure the sensor works
properly and accurately. Test the light sensor by giving it light or covering to see different readings.
After testing remember to unplug the unit to continue installing other sensors.
