User Manual

SENSOR MODELS
This manual covers the SDI-12 communication protocol, original quantum sensor model SQ-421. Additional models
are covered in their respective manuals.
Model
Signal
Calibration
SQ-421
SDI-12
Sunlight and Electric light
SQ-110
Self-powered
Sunlight
SQ-120
Self-powered
Electric light
SQ-311
Self-powered
Sunlight
SQ-321
Self-powered
Electric light
SQ-313
Self-powered
Sunlight
SQ-323
Self-powered
Electric light
SQ-316
Self-powered
Sunlight
SQ-326
Self-powered
Electric light
SQ-212
0-2.5 V
Sunlight
SQ-222
0-2.5 V
Electric light
SQ-214
4-20 mA
Sunlight
SQ-224
4-20 mA
Electric light
SQ-215
0-5 V
Sunlight
SQ-225
0-5 V
Electric light
SQ-420
USB
Sunlight and Electric light
SQ-422
ModBus
Sunlight and Electric light
Sensor model number and serial number
are located near the pigtail leads on the
sensor cable. If you need the
manufacturing date of your sensor, please
contact Apogee Instruments with the serial
number of your sensor.