Monnit Sensor Heartbeats represent the frequency with which our sensors report data to the iMonnit Software platform. In the Monnit protocol, our sensors always initiate the communication. There is no way in iMonnit to manually prompt a sensor to communicate. As a result, you need to know how to configure Monnit Sensor Heartbeats and Aware State Heartbeats.
Most Monnit Sensors are not limited to a minimum Heartbeat configuration by the hardware but rather by iMonnit. In many scenarios, the desired Heartbeat Interval may dictate which iMonnit Software version you wish to use. This article will help you understand sensor Heartbeats and which iMonnit version might be best for your application.
More Data isn’t Always Better
It’s common for many of us to assume that having more data is better in all cases. Using this logic, configuring a sensor with the most frequent Heartbeat is always better. However, an important consideration is that Monnit Sensors send a reading when a specific condition is detected; therefore, it isn’t always necessary to have a more frequent Heartbeat. In fact, in most cases, reviewing sensor history to identify the sequence of specific events is much easier and more efficient if there are fewer data points to review.
Why Limit Heartbeats?
There are three reasons iMonnit limits minimum Heartbeat frequency:
- Efficient use of data
- Efficient use of battery power
- The expense of data transmission and storage
The number of data points to store for each sensor can add up, possibly requiring enormous storage. Limiting the Heartbeat when using the online cloud storage helps iMonnit service costs to stay low. It also encourages users that need more frequent Heartbeats to store and manage data locally.
The iMonnit Online Portal
iMonnit Online —Free Basic: 120 minutes
iMonnit Online —Premiere subscription: 10 minutes
iMonnit Online —Premiere subscription with additional purchase of HX Credits: 1 minute
If you use the free iMonnit Basic subscription, there is no additional cost, and your most frequent Heartbeat configuration is 120 minutes.
Note: If using a trigger sensor such as an Open-Closed Sensor, you may see the sensor report data before the scheduled 120-minute Heartbeat. However, the Aware State configuration cannot be changed using the free Basic subscription.
If you use the standard paid iMonnit Premiere subscription, your more frequent Heartbeat configuration is 10 minutes. You will also have access to the Aware State configuration on trigger sensors.
If you need Heartbeats as frequently as one minute, you can purchase HX Credits. The iMonnit HX Credits are used after your sensor has reported 144 data points in a day. Any number of data points for a single sensor over 144 will charge from your HX Credits pool.
1 second 
1 second [1:1]
1 second [1:2]
Using an ALTA Serial MODBUS Gateway
1 second [1:3]
Operating on a private MODBUS TCP or SNMP Interface on an Ethernet Gateway
The Heartbeat configuration when utilizing these interfaces is limited by the version of iMonnit Software used to configure the sensors. Monnit Sensors cannot be configured using the MODBUS TCP/SNMP Interface of an Ethernet Gateway. Instead, you can configure your sensors using the desired iMonnit Software (with its set limitations), then disable the connection to iMonnit, and the sensors will maintain their configurations. Therefore the Heartbeat frequency of your sensors is limited to the version of software used to configure the sensors before unlocking and disabling the Default Interface of your Ethernet Gateway.
HX Heartbeat Credits
Serial MODBUS Gateway
- So long as your sensor hardware supports it (most sensors do), sensors can be configured to have Heartbeats as frequently as one second.