Programming instructions

Designer’s Guide 39
Calsense
Soil Moisture Sensor (model 1000-S)
The Calsense Moisture Sensor is a solid-state tensiometer that measures moisture content in the soil
(Figure 18
). The sensor includes data transmission circuitry that sends moisture level readings to the
controller over the same field wires that operate the valve. The entire unit is encased in epoxy to protect
the electronics from moisture. There is no maintenance or calibration required for the life of the sensor,
and it is unaffected by temperature, salinity, or changes in pH.
Using the Soil Moisture Sensor to measure the available water in the pore space of soil, the Calsense
ET2000e determines how much of each station's programmed time is necessary to maintain a set
moisture level before irrigation begins. This is based on the actual moisture reading compared to the
user-determined moisture setpoint. At the beginning of each irrigation cycle, the controller measures the
current moisture reading. If the moisture reading is higher than the setpoint, the controller does not
irrigate the station and sets a flag in the reports to notify the user. In the event the controller fails to
receive a valid sensor reading, the controller automatically irrigates the full amount of programmed time
for all stations operating under that sensor.
When using Soil Moisture Sensors, a representative station for each different climatic- and plant-
material zone should have its own sensor. This station becomes a master station. Slave stations are
stations without sensors that are assigned to a master station and share similar water requirements. The
user chooses groups of stations controlled by the same Soil Moisture Sensor during initial setup of the
irrigation controller. Stations can be easily changed or moved from one sensor to another through
programming. It is recommended that 1 sensor be used for every 4 active irrigation valves. For example,
an ET2000e-24 controller requires 6 moisture sensors, while an ET2000e-32 requires 8.
Note: If the irrigation design involves operating multiple valves using a single sensor, the valves must be
similar in vegetation, exposure, and so on for moisture sensing to work properly.
Placement Guidelines
A Calsense Field Service Representative can help make the placement decision of Soil Moisture Sensors.
A note to the contractor to contact Calsense in determining sensor placement should be listed on the
plans or in the specification. It is required that the contractor completes the following before Soil
Moisture Sensor placement:
• Irrigation controller installed and operational
• Remote Control Valve (RCV) field wires connected to the irrigation controller according to plan
• All lateral systems complete with heads on and RCVs wired
• Plant material in shrub areas planted
The following placement guidelines should be followed when flagging moisture sensor locations:
• Location is representative of the areas being managed
• Location is not quickly flooded during irrigation
• Location is not subject to damage or disturbance during maintenance
• Location is irrigated evenly from 2 sprinkler heads on the same valve
• Sensor is placed in the root zone of healthy plants
• When controlling slopes, sensor is located two-thirds up from the toe of slope