HOBO MX pH and Temperature Logger (MX2501) Manual
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choosing statistics options). In burst mode, logging occurs at
a different interval when a specified condition is met. See
Burst Logging
for more information. Tap Done.
11. Enable or disable Show LED. If Show LED is disabled, the
alarm and status LEDs on the logger will not be illuminated
while logging (the alarm LED will not blink if an alarm trips).
You can temporarily turn on LEDs when Show LED is
disabled by pressing the button on the logger for 1 second.
12. Select the power saving mode, which determines when the
logger will “advertise” or regularly send out a Bluetooth
signal for the phone or table to find via HOBOmobile.
•
Bluetooth Always Off.
The logger will only advertise
during logging when you push the switch on the logger.
This will wake up the logger when you need to connect to
it. This option uses the least battery power.
•
Bluetooth Off Water Detect.
The logger will not
advertise when the presence of water is detected. Once
the logger is removed from the water, advertising will
automatically turn on, thereby not requiring you to push
the switch to wake up the logger when you need to
connect to it. This option preserves some battery power.
Note:
The logger will check for the presence of water
every 15 seconds when this is option is selected.
•
Bluetooth Always On.
The logger will always advertise.
You will never need to push a switch to wake up the
logger. This option uses the most battery power.
13. Tap Start in the upper right corner of the Configure screen
to load the settings onto the logger.
Logging will begin based on the settings you selected. See
Deploying and Mounting the Logger
for details on mounting
and see
Reading Out the Logger
for details on downloading.
Setting up Alarms
You can set up alarms for the logger so that if a sensor reading
rises above or falls below a specified value, the red logger LED
will blink and an alarm icon will appear in HOBOmobile. This
can alert you to problems so you can take corrective action.
To set an alarm:
1. Tap the HOBOs icon and tap the logger to connect to it. If
the logger was configured with Bluetooth Always Off
enabled, push the switch on the logger to wake it up. If the
logger was configured with Bluetooth Off Water Detect and
is currently underwater, remove it from the water.
2. Once connected, tap Configure.
3. In Sensor & Alarm Setup, tap Temperature or pH.
4. Enable the High Alarm if you want an alarm to trip when the
sensor reading rises above the high alarm value. Drag the
slider to the reading that will trip the alarm or tap the value
field and type a specific reading. In the example, an alarm
will trip when the temperature rises above 85°F.
5. Enable the Low Alarm if you want an alarm to trip when the
sensor reading falls below the low alarm value. Drag the
slider to the reading that will trip the alarm or tap the value
field and type a specific reading. In the example, an alarm is
configured to trip when the temperature falls below 32°F.
Note:
The actual values for the high and low alarm limits are
set to the closest value supported by the logger.
6. Under Raise Alarm After, select the duration before an
alarm is tripped and tap Done in the Alarm Duration screen.
7. Select either Cumulative or Consecutive Samples. If you
select Cumulative Samples, then the alarm will trip when
the time the sensor is out of range over the course of the
deployment is equal to the selected duration. If you select
Consecutive Samples, then the alarm will trip when the
time the sensor is continuously out of range is equal to the
selected duration. For example, the high alarm for
temperature is set to 85°F and the duration is set to 30
minutes. If Cumulative is selected, then an alarm will trip
once a sensor reading has been at or above 85°F for a total
of 30 minutes since the logger was configured; specifically,
this could be 15 minutes above 85°F in the morning and
then 15 minutes above 85°F again in the afternoon. If
Consecutive is selected, then an alarm will trip only if all
sensor readings are 85°F or above for a continuous 30-
minute period.
8. Tap Done and repeat steps 3–8 for the other sensor if
desired. Note that when both alarms are configured, an
alarm is raised when either sensor is in an alarm condition.
9. Back in the Configure screen, select one of the following
options to determine how the alarm indications are cleared:
•
Logger Reconfigured.
The alarm indication will display
until the next time the logger is reconfigured.
•
Sensor in Limits.
The alarm icon indication will display
until the sensor reading returns to the normal range
between any configured high and low alarm limits.
10. Tap Start in the Configure screen to load the alarm settings
onto the logger if you are ready to start.
When an alarm trips, the red logger LED blinks every 4 seconds
(unless Show LED is disabled), an alarm icon appears in the app,
and an Alarm Tripped event is logged. The alarm state will clear
when the readings return to normal if you selected Sensor in
