
HOBO® MicroRX Station (RX210x) Quick Start 
Tools required: 
• Phillips-head screwdriver for installing the water level sensor  
(RX2103 and RX2104 models) or mounting the station to a flat 
surface with screws. 
• A ½ inch box wrench if you are using U-bolts to mount the station  
to a tripod or mast. 
• Other tools may be required depending on the accessories you  
are using for your station deployment. 
Log in to HOBOlink. 
1 
Go to www.hobolink.com and log in to an existing account or 
create a new one. You’ll receive an email to activate the account. 
Register the station. 
2 
In HOBOlink, click Devices, then RX Devices. Click the Register a 
Device link. Give the station a name and enter the serial number 
and device key from the label inside the station door. 
Note: If you are using your own micro SIM card, follow the 
instructions at www.onsetcomp.com/support/ 
manuals/23845-installing-micro-sim-rx2100-station before 
continuing. 
Mount the station. 
3 
There are three ways to mount the station using the built-in 
mounting tabs. Note: You can also defer mounting until the end 
of the process if you want to perform initial testing. 
• Use the two sets of outer  
holes and 1-5/8 inch saddleclamp U-bolts to attach the 
logger to a tripod or mast 
(this is the recommended 
method for mounting on a 
mast). Do not use U-bolts 
without the saddle clamps 
as that could bend the 
mounting tabs and damage 
the housing or compromise 
the weatherproof seal. The 
flat portion of the saddle 
clamps should be against 
the mounting tabs. 
• Use the included cable ties  
with the two sets of inner  
holes to affix the logger to a PVC pipe or mast. 
• Use the included screws and washers with the two sets of  
outer holes to adhere the logger to a wall or flat surface. 
Important: See the RX2100 manual for additional deployment 
guidelines at www.onsetcomp.com/support/manuals/23808rx2100-manual. 
Remove the cable channel. 
4 
Remove the cable 
channel making note 
of how it is oriented. 
Notch where the key on the 
bottom of the cable channel 
is installed 
Inner mounting holes; use with 
cable ties 
Outer mounting 
holes; use with 
screws and washers 
or saddle-clamp  
U-bolts 
Inner mounting holes; use 
Cable channel 
Install the water level sensor if applicable 
5 
(RX2103 and RX2104 models). 
a. Insert the water level 
sensor cable jack into the 
water level sensor. Screw 
on locking nut (hand tight). 
Important: Make sure the O-rings on the cable jack end and 
the cable and sensor mating housing surfaces are clear of any 
debris. Any contamination of these surfaces can cause leaks 
that may lead to sensor failure. 
b. Plug the other end of the water level sensor cable into the port 
on the right side of the board. 
Plug the water 
level sensor 
cable into this 
port 
Secure the cable 
with two screws 
c. Use a Phillips head screwdriver to secure the water level sensor 
cable in place with the two screws provided. 
d. Route the cable through the far-right hole in the cable channel. 
Plug in smart sensors if applicable. 
6 
a. Plug in smart sensors into the ports below the LCD. 
Plug in smart sensors into 
the five ports 
b. Route the cables through the holes in the cable channel. There 
are slits in the cable channel above each hole to guide the 
cable into the hole. You may need to slightly bend the ends of 
the channel to reveal the slits and push each cable into the 
hole that lines up with the corresponding sensor connector. 
Grease and reinstall the cable channel. 
7 
a. Use the integrated plugs to fill any unused holes. Bend the 
plugs up to push them into the holes. Once a plug is partially 
pushed through, you can pull on the part of the plug that is 
inside the case. You may need to bend the ends of the channel 
slightly to widen the holes for installing the plugs. 
b. Lightly coat the portion of the sensor cables that will be in the 
cable channel with a small amount of silicone grease (about the 
size of a pea). 
c. Lightly coat the bottom and two sides of the cable channel with 
silicone grease. 
d. Reinstall the cable channel in the station making sure the key 
on the bottom is inserted in the notch in the station enclosure 
as pointed out in step 4. 
23807-B MAN-RX2100-QSG 

8 
Plug in the battery and wait for the station 
to connect to HOBOlink. 
Note for RX2103 and RX2104 models: If you are using the 
water level sensor, make sure it is plugged in before 
powering up the station in this step. Otherwise, only 
barometric pressure will be logged. 
a. Plug in the battery cable. For RX2102 and RX2104 models, 
plug in the solar panel cable for the built-in solar panel. 
Plug in the solar 
panel here (RX2102 
and RX2104) 
10 
11 
Start Logging. 
Press the Start button on the station to start logging. The 
station will connect to HOBOlink and then logging will begin. 
If you are not using a water level sensor, then the setup is 
complete. Measurements are uploaded to HOBOlink each 
time the device connects. Go to www.hobolink.com and click 
Help for details on checking the latest conditions, setting up 
dashboards, exporting data, and more. 
Obtain a reference water level reading 
(RX2103 and RX2104 models). 
Make sure the water level sensor is deployed in its final 
location and that the station is logging. Take a reference level 
reading, measuring the water level from the desired 
reference point. 
Important: Note the reference level reading as well as the 
date and time it was taken. 
Connect the 
battery cable here 
b. Once the battery cable is plugged in, “Initializing System” 
will flash on the LCD. A checkmark appears next to 
“System” after the station initialization is complete. 
c. After the station powers up, it will connect to HOBOlink 
automatically within two minutes. The cellular icon and 
“Connection” will flash while the connection is underway. 
Once the connection is complete, a checkmark appears 
next to Last Connection. Note that the entire initialization 
process may take several minutes; wait until Last 
Connection and the checkmark appears before continuing 
to step 9. 
A checkmark 
appears next to 
Last Connection 
after connecting 
to HOBOlink 
9 
Configure the station in HOBOlink. 
In HOBOlink, click Devices, then RX Devices, and click the   
icon next to your station. Make changes and click Save on 
each screen as you configure the following: 
• General system settings (nickname, time zone, and  
image) 
• Readout settings (connection interval and night mode) 
• Smart sensor logging and sampling interval 
• Settings for each smart sensor (e.g. labels, graph, and 
scaling) 
Important for RX2103 and RX2104 models: Do not 
configure the water level and water flow channels yet. Set 
the logging and sampling interval for the water level 
sensors module and optionally add labels, scaling, or 
enable graphing. Continue to step 10 to start logging and 
then obtain a water reference level reading in step 11 
before configuring water level and water flow. 
1-800-LOGGERS (564-4377) • 508-759-9500 
www.onsetcomp.com/support/contact 
12 
Configure water level, water flow channels 
in HOBOlink (RX2103 and RX2104 models). 
© 2019 Onset Computer Corporation. All rights reserved. Onset, HOBO, and HOBOlink are registered trademarks of Onset 
Computer Corporation. All other trademarks are the property of their respective companies. 
This product has been manufactured by Onset Computer Corporation and in compliance with Onset’s ISO 9001:2015 Quality 
Management System. 
Perform the following steps in the field in HOBOlink with a 
mobile device to verify that the system is logging the water 
level correctly while you are still at the station site. 
a. In HOBOlink, click Devices, then RX Devices, and click the 
 icon next to your station. 
b. Under the water level sensors module in the Configuration 
menu, select Water Level. 
c. Click the checkbox to Enable Channel. 
d. Click the checkbox to Enable Graph. Type a label (optional). 
e. Enter the reference water level and date and time noted in 
step 11. 
• If the water level surface is below the reference point,  
enter the reference water level as a negative number. 
• If the water level surface is above the reference point,  
enter the reference water level as a positive number. 
f. Select the appropriate water density. 
g. Click Save. 
If you are configuring water flow and using one of the 
supported weir or flume types, follow steps h–l. 
h. Select Water Flow from the Configuration menu. 
i. Click the checkbox to Enable Channel. 
j. Click the checkbox to Enable Graph. Type a label (optional). 
k. Choose the measurement method for water flow and 
enter the appropriate information for the method 
selected. 
l. Click Save. 
Water level and flow data will be calculated starting with the 
next connection to HOBOlink. If you don’t want to wait for 
the next scheduled connection, press the Cloud button on 
the station LCD to connect to HOBOlink immediately. Note 
that the reference water level information entered in this 
step will not affect any previously logged data. 
Go to www.hobolink.com and click Help for details on 
checking the latest conditions, setting up dashboards, 
exporting data, and more. 
For additional information:
Station Manual for specifications and detailed operation, 
including deployment and mounting guidelines, and more 
information on water level sensor configuration. Go to 
www.onsetcomp.com/support/manuals/23808-rx2100-manual 
or scan the code at left. 
See the HOBO MicroRX 
23807-B MAN-RX2100-QSG