USER MANUAL
TYPE ML-2012/13
Manufacturers of low power instruments
page 16
4
Reference
4.1 Principle of Operation
Your ML-2012/13 Data logger is capable of collecting and storing data of multiple
sensors. To accomplish
this, many tasks are performed. These “tasks” are scheduled and executed on their specified time. The
timing of this process is very important and is determined by the internal scheduler. This scheduler keeps
track of all the internal states of the various tasks and assigns processor time to the different tasks. Each
task is executed on its own interval. To understand more about this, Fist we explain the different intervals.
There are three different intervals:
1) Sample Interval
2) Data Log Interval
3) Send Interval
4.1.1 Sample interval
The sample interval is the interval on which a sample from the sensor is taken
(expected).
So,
measurements from sensors are done at the sample interval. The sample interval is valid ONLY when the
device is in the active state. When the data logger is in sleep-mode, the tasks, triggered by the sample
interval will NOT execute.
4.1.2 Data logging interval
This interval determines when a data value, obtained by the sample interval-task, is stored onto the SD-
card. This type of interval is ALWAYS valid. So, even when the data logger is in sleep-mode, it will wake
up when the Data logging Interval has reached its count.
4.1.3 Send Interval
The send interval determines the interval on which data is send, via the internal modem. This interval is
ALWAYS valid, even if the data logger is in sleep-mode.
4.1.4 Example
Let’s evaluate the following settings of the data logger:
-
Sample Interval: 5 seconds
-
Data Log Interval: 10 minutes
-
Send Interval: 3 hours
When the configuration is ready and the user disconnects the USB-Cable;
1. Data logger is switched into sleep-mode, and current draw is reduced to a minimum level.
2. The Sample interval of 5 seconds is discarded, because this interval is only active when the data
logger is NOT in sleep-mode. So nothing happens until the Data Log interval has reached his count.
(So this happens on 0, 10, 20, 30, 40, 50 minutes every hour)
