Understanding Poll Intervals
Poll Intervals in Gateways and Add-On Devices
Poll Intervals are an important configuration for the desired operation of Add-On Devices such as Control Units and Local Alerts. The process of Polling allows your Add-On Devices to respond to commands or input with a desired response-time.
There are two Polling events to consider. First, gateways must receive the command by polling the Monnit software. Once the gateway has received the command, the Add-On devices must Poll the gateway to execute the command. Therefore there is a Poll Rate in the gateway Settings, and a Poll Rate in the Add-On device’s Settings. This article will provide the details needed for understanding polling configuration.
The process of a command being executed on an Add-On device starts by the command being initiated in the Monnit software. In order for the command to reach the Add-On device, the gateway must Poll the software and queue the command for the Add-On device. Therefore the gateway offers a Poll Rate configuration which is the frequency by which the gateway checks to see if there is an Add-On device command to be executed by a device on the gateway’s Sensor Network.
If the Poll Rate is set to 0, the gateway will Poll the Monnit software on the gateway’s Heartbeat.
Not all gateways offer the Poll Rate configuration. For example, since data usage is a consideration with cellular gateways, some cellular gateways do not offer a Poll Rate configuration under their Settings tab.
The gateway’s Poll Rate can be found under the gateway’s Settings > Poll Rate.
Add-On device Poll Interval
The Poll Interval of the Add-On device is how frequently the Add-On device communicates with the gateway to see if there is a command that the gateway has queued to be executed. This means the minimum time in which an Add-On device can execute a command is the gateway’s Poll Rate + the Add-On device Poll Interval + transmission time. This is an important consideration when configuring your Monnit system if there is a minimum time by which you need your Add-On device to respond to a command.
If the sensor’s Poll Interval is set to 0, the sensor will Poll the gateway on the sensor’s Heartbeat.
The Add-On device’s Poll Rate can be found under the sensor’s Settings > Poll Interval.
For this example, we will be using an Ethernet Gateway 4 configured with a (default) 5 minute heartbeat and 0 Poll Rate, and a Control Unit configured with a 10 minute Heartbeat and a 1 minute Poll Interval. With these configuration the maximum response time a control command might take to reach the Control Unit would be 6 minute (plus transmission time). The minimum time a control command might take to reach the Control Unit would be just over 1 minute (plus transmission time).
(Control Unit last checked with a standard Heartbeat at 5:04:30 PM)
5:12:05 PM - Gateway checks in with iMonnit Online with a standard Heartbeat at a 5 minute interval and Polls iMonnit for Control Commands (none present)
5:12:30 PM - Control Unit Polls the gateway for Control Commands (none present)
5:13:30 PM - Control Unit Polls the gateway for Control Commands (none present)
5:14:30 PM - Control Unit checks in with the gateway with a standard Heartbeat and Polls for Control Commands (none present)
5:15:30 PM - Control Unit Polls the gateway for Control Commands (none present)
5:15:41 PM - Action in iMonnit Online queues Relay 1 On command
5:16:30 PM - Control Unit Polls the Gateway for Control Commands (none present, gateway has not yet Polled iMonnit Online since Action was triggered)
5:17:05 PM - Gateway checks in with iMonnit Online with a standard Heartbeat at a 5 minute interval and Polls iMonnit for Control Commands (Relay 1 On command received from iMonnit Online and queued for delivery to Control Unit)
5:17:30 PM - Control Unit Polls the gateway for Control Commands (Relay 1 On command detected) - Control Unit Relay 1 set to On
In the above example, the Action triggered a Control - Relay 1 On command in iMonnit Online at 5:15:41 PM, and the Control Unit receive the command at 5:17:30 PM. Since the gateway had the Poll Rate set to 0, the gateway was only polling iMonnit Online for Control Commands on its Heartbeats. The Control Unit was then Polling the gateway every 1 minute for Control Commands. Therefore the Control Unit received the Control Command within 1 minute of the gateway’s Heartbeat where it received the Control Command from IMonnit Online.
Understanding Poll Intervals is critical to getting the expected response time for your Add-On devices such as Control Units and Local Alerts. If you have additional inquiries regarding the operation of Poll Intervals, feel free to contact Monnit Support.