NITOR Model 900M - Instruction Manual
(Please refer to the CD for more detailed information)
The Watermark Monitor automatically reads up to eight (8) sensors and
stores the readings for collection and display by a computer. Watermark soil
moisture, soil temperature, Irrometer Model RSU (4-20mA transducer),
switch closure, voltage and 4-20mA sensors can be read and recorded.
SENSOR INSTALLATION
Watermark soil moisture sensors must be conditioned prior to installation.
The sensors should be soaked to saturation and then dried fully, twice, and
then soaked to saturation again prior to installation. This conditioning of the
sensors ensures quick response to changing soil moisture conditions. If a
sensor is only soaked and then installed, several irrigation cycles must pass
before the sensor will respond accurately. Soak the sensors in a bucket of
water for several hours to saturate them. Hang them up overnight to dry
sufficiently. After conditioning they are ready for installation. Sensors
MUST be installed in an active portion of the root zone of the plant to be
monitored, either vertically or up to a 45° angle. Bore a 7/8 diameter
access hole to the desired depth, then insert the sensor. Be careful to
ensure a snug fit between the sensor and the surrounding soil. Then
backfill the hole firmly. The access hole can be made by pounding a 7/8
diameter bar (or ½ size IPS pipe) to the desired depth, then extracting
the bar, being careful not to disturb the soil surrounding the borehole. With
hard or rocky soil, a larger diameter hole can be made with a soil auger. Mix
the auger cuttings with water to create a slurry and pour into the borehole.
Then insert the sensor into the hole. Once the slurry dries, the sensor will
have been grouted in to ensure good contact with the soil. The sensor
can be attached to ½ class 315 PVC pipe with a PVC to ABS cement. The
pipe becomes a conduit to protect the sensor wires. Also, this makes the
sensor easier to push into the access hole and remove, if desired. The top
of this pipe section should be capped or plugged so surface water does not
travel down to the sensor. Drill a small hole in the side of the pipe just above
the sensor to allow water to drain away if it becomes trapped in the pipe.
The soil temperature sensor should be installed in the soil near a
representative soil moisture sensor. More than one soil temperature
sensor can be used. Several soil moisture sensor readings can be
compensated by a single soil temperature sensor. Bore a
1/2 diameter hole in the soil and insert the temperature sensor. Then
backfill the hole. Refer to Irrometer installation instructions for proper instal-
lation of Model RSU. The switch closure sensor is a pressure gauge with a
¼ NPT connection that has an adjustable switch mounted to its face. The
gauge is installed into the irrigation pipeline. The pressure range of the
gauge should be selected so that the normal system pressure is in the
middle third of the gauge range. The normal system pressure is the set
point which will trip the switch, indicating that an irrigation is taking place.

#86
WARRANTY: The IRROMETER COMPANY warrants its products against defective
workmanship or materials under normal use for one year from date of purchase.
Defective parts will be replaced at no charge for either labor or parts if returned to
the manufacturer during the warranty period. The sellers or manufacturers only
obligation shall be to replace the defective part and neither seller nor manufacturer
shall be liable for any injury, loss or damage, direct or consequential,arising out of
the use of or inability to use the product. This warranty does not protect against
abuse, shipping damage, neglect, tampering or vandalism, freezing or other damage
whether intentionally or inadvertently caused by the user.
TROUBLESHOOTING
Please reference the suggestions below, look in the Help section of WaterGraph or
contact Irrometer for further assistance.
No Display: Check battery, replace if <7.2 Volts. Try RESET, see below.
Unusual readings: The following are possible readings that may be displayed
instead of a soil moisture, temperature or switch position: DRY- meaning the
resistance is so high that there must be an open wiring connection on a Watemark or a
low temperature reading (frozen) on a temperature sensor, check for broken wires.
SHORT- meaning the resistance is so low that the circuit must be shorted on a
Watermark, or off scale on a temperature sensor, check for shorts.
Reading doesnt change: Sensor may have lost contact with the soil. Re-install sensor,
being sure to establish good soil contact.
COM Port issues: Direct serial connection should normally be COM 1 to COM 4. If a
COM port is available the Autodetect function will find the Monitor. If a COM port not
available, check to see if a PDA Sync program is active and may be capturing the COM
port. This is very typical with laptops. The Palm Hot Sync Manager or the Microsoft
Active Sync Manager icon will appear as active in the lower right side task bar of the
desktop. Right click on it and select Exit to close it and free up the COM port. Closing
WaterGraph and re-opening it may help to establish communication with the COM port,
if it is available. Also, re-starting the computer can clear up COM issues.
Connection with a USB to Serial adapter cable: These adapters create virtual COM
ports from a USB connection. The adapter will come with software (drivers) that
must be installed on the computer. Normally the COM port number created with
these adapters will be COM 5 to COM 8. The COM address of the adapter can be
determined by navigating to: My Computer right click to get Properties
Hardware Device Manager. Then look in the USB or Port sections to see if the
adapter is listed. Select it and right click to view the properties of the device and it
should show the COM port assigned.
Soft RESET: Use the end of a paper clip or other small object to press the RESET button
located underneath the small hole just above the battery on the faceplate.
Hard RESET: Remove the battery. Press and hold the RESET button down for at
least 5 seconds. Then re-insert the battery.
Firmware upgrading: Using the Update Datalogger command in the Tools menu
in WaterGraph, select the new firmware version (.hex format) and press Open. If
the upload process is interrupted, then Monitor will be locked up and its display
will stay on Uploading. If this happens, use the Recover Monitor Update
command in the Tools menu to finish the upload process.
The Company

Mail: P.O. Box 2424 Riverside, CA 92516
Phone: (951) 689-1701 Fax: (951) 689-3706
TechSupport@Irrometer.com

www.Irrometer.com
MONITOR MOUNTING
The Monitor housing should be mounted on a wall or post nearby the sen-
sors. Use the enclosed template to mark screw holes for mounting the
enclosure. Set the Monitor over the top screw with the keyhole then
secure with screws in the lower holes. Run sensor wires through the strain
relief fittings on the bottom of the Monitor. Tighten the gland on the fitting
to compress the rubber insert to secure the wires and weather-proof the
enclosure. The Monitor can be located some distance from the sensors to
facilitate access. See sensor wiring recommendations below. If using the
Quick Disconnect version, attach the field sensor wires to the wire tail from
the connector using waterproof wire splices. Be careful to follow the wire
markings to be sure the sensor wires are attached to their corresponding
terminals. The quick disconnect fittings will twist apart for easy removal.
SENSOR WIRING
Additional wire can be added to the sensors for long distances.
Please adhere to the following wire size recommendations when adding
wire: Distance
Wire Size
Up to 1000 ft. (300 m)
AWG UF 18 (1.02 mm, .82 sq mm)
1001 to 2000 ft. (600 m) AWG UF 16 (1.29 mm, 1.31 sq mm)
2001 to 3000 ft. (900 m) AWG UF 14 (1.63 mm, 2.08 sq mm)
Multi-conductor wire can be used and twisted pairs are not necessary. All
splices should be made with direct burial type waterproof splices, Spears DBY
®
or similar. Be sure to mark each pair of sensor wires indicating what type of
sensor is attached and the placement depth. Attach sensor wires to the
appropriate terminals as determined by your sensor selection. The terminal
strips have spring tensioned lever terminals. First, insert the wire in the
bottom of the terminal, then push down on the black lever. The lever can be
lifted with a finger, or small screwdriver inserted in the slot, for wire removal.
Terminals will accept wire up to AWG 16. If a larger size is used, run a short
length of smaller wire to the terminal strip.
BATTERY INSTALLATION
Insert a 9 Volt battery, connectors first, into the battery holder observing
polarity markings. Snap the back end of the battery fully into the holder.
An alkaline battery should provide approximately one year of operation.
After the battery is installed, the display shows Clock Error and Run
Setup. After 5 seconds the Monitor display go to sleep to conserve
battery power. Pressing the green button will wake up the Monitor. If
you see Fault Error #__, please note the error number and contact the
factory for troubleshooting. An automatic check of the battery capacity is
performed daily. The status is displayed every time the Monitor is turned
on. Whenever LOW is in the display, it indicates it is time to r