Setting Up Alarms - Hobo MX Series Manual

4. Use the Onset well cap if it is a 5 cm (2 inch) well.
Otherwise, use a 1/4-inch bolt of sufficient length to span
the well top or washer. Mount the logger as follows:
• The top end must be above any metal well to ensure
good wireless transmission.
• Make sure there is access for measuring the water level
in the well. In some cases, such as when using the Onset
well cap, it will be necessary to pull the top end of the
logger out of the well to get a water level meter sensor
into the well.
• Make sure the logger cannot accidentally fall in the well.
• If the cable is too long, loop the cable and secure the
cable with multiple zip ties to ensure the loop does not
slip. The looped cable should be tight enough that the
cable can be easily pulled out of the well if necessary, but
it must not bend the cable any tighter than a 1.25 cm (0.5
inch) radius to prevent damage to the cable.
5. Measure the water level from the desired reference point
(top of pipe, ground level, or sea level) and enter it in the
app. Note that you may need to pull the top end out of the
well to gain access for measuring the water level within the
well. Follow these guidelines for determining the reference
level:
• To maximize accuracy, allow 20 minutes after deploying
the logger before measuring water depth to allow the
logger to reach temperature equilibrium with the water.
• If the well is too small in diameter to measure the water
depth while the logger is deployed, measure the water
depth before deployment, then deploy the logger
immediately.
• If the water level surface is below the reference point as
shown below, enter the reference water level in the app
as a negative number.
1-508-759-9500 (U.S. and International)
1-800-LOGGERS (U.S. only)
HOBO MX Water Level Logger (MX2001-0x) Manual
• If the water level surface is above the reference point as
shown below, enter the reference water level in the app
as a positive number.
• If you are using the sensor as the reference point as
shown below, enter the reference water level in the app
as zero and start the logger before the sensor is in the
water. The logged water level readings will represent the
height above the sensor.

Setting up Alarms

You can set an alarm to trip on the logger when a sensor
reading rises above or falls below a specified value. This can
alert you to problems so you can take corrective action. To set
an alarm:
1. Tap Devices. Tap the logger in the app to connect to it and
tap .
2. If you are going to set up a water level alarm, you must
enter the reference water level and water density before
setting the alarm levels.
3. Tap the Differential Pressure sensor if you want to set a
water level alarm. Tap the Temperature sensor to set a
temperature alarm. You cannot configure alarms for
absolute pressure. Note: The fixed logging mode must be
set to normal to configure a water level alarm.
4. Select High if you want an alarm to trip when the sensor
reading rises above the high alarm value. Drag the slider or
type a value to set the high alarm value. If you are
configuring a water level alarm, enter the limit value for
water level and app will show the differential pressure level
that will be used to trigger the alarm in the logger.
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