LISA-U1 series - System Integration Manual
3G.G2-HW-10002-3
Preliminary
Features description
Page 114 of 125
The best solution is always to properly design the system where the module is integrated. Nevertheless an extra
check/security mechanism embedded into the module is a good solution to prevent operation of the device
outside of the specified range.
3.10.1
Smart Temperature Supervisor (STS)
The Smart Temperature Supervisor is activated and configured by a dedicated AT+USTS command. Please refer
to
u-blox AT Commands Manual
[2] for more details.
The wireless module measures the internal temperature (Ti) and its value is compared with predefined thresholds
to identify the actual working temperature range.
Temperature measurement is done inside the wireless module: the measured value could be different
from the environmental temperature (Ta).
Warning
area
t
-1
t
+1
t
+2
t
-2
Valid temperature range
Safe
area
Dangerous
area
Dangerous
area
Warning
area
Figure 61: Temperature range and limits
The entire temperature range is divided into sub-regions by limits (see Figure 61) named t
-2
, t
-1
, t
+1
and t
+2
.
Within the first limit, (t
-1
< Ti < t
+1
), the wireless module is in the normal working range, the Safe Area
In the Warning Area, (t
-2
< Ti < t
.1
) or (t
+1
< Ti < t
+2
), the wireless module is still inside the valid temperature
range, but the measured temperature approaches the limit (upper or lower). The module sends a warning to
the user (through the active AT communication interface), which can take, if possible, the necessary actions
to return to a safer temperature range or simply ignore the indication. The module is still in a valid and good
working condition
Outside the valid temperature range, (Ti < t
-2
) or (Ti > t
+2
), the device is working outside the specified range
and represents a dangerous working condition. This condition is indicated and the device shuts down to
avoid damage
For security reasons the shutdown is suspended in case an emergency call in progress. In this case the
device will switch off at call termination.
The user can decide at anytime to enable/disable the Smart Temperature Supervisor feature. If the
feature is disabled there is no embedded protection against disallowed temperature conditions.
Figure 62 shows the flow diagram implemented in the LISA-U1 series modules for the Smart Temperature
Supervisor.
