3.
Reinstall the batteries.
•
When batteries are fully reinstalled, the normal power up sequence occurs.
6.8.3 Low Battery Voltage
The sensor has a built-in power supply that converts the battery voltage to that which is required by the internal circuitry.
The sensor is designed to operate with a battery voltage range of approximately 2.0 V to 3.7 V. If the battery volrage falls
below approximately 2.0 V (approximately 1.0 V on each cell), the batteries do not have enough capacity to support an RF
transmission and the voltage will collapse when this process is attempted.
If a sensor is operating with batteries in this state, the following sequence occurs:
1.
The sensor powers up as indicated by all three LEDs solidly displaying for three seconds.
2.
Depending on the battery capacity, the following scenarios may occur:
•
The sensor may join the network as indicated by two beeps and a solid blue LED for two seconds.
However, the sensor typically will not have enough capacity to transmit the first payload, which happens
five seconds after a successful join. At this point, a short green LED blip will occur as the sensor tries to
transmit the first payload but the battery voltage collapses enough to cause the processor to reset.
•
If the batteries are extremely low, the battery voltage will collapse while the sensor is trying to join the
network and cause the processor to reset. In this situation, the three LEDs come on solid, which is what
happens after a processor reset. The three LEDs may cause the battery voltage to sag or the subsequent
light strobing and sensor join process may cause the battery voltage to sag and the processor will reset.
•
This cycle of processor resets followed by some activity on the sensor continues until the batteries are
completely depleted.
6.9 FLEXio Interface
6.9.1 FLEXio Pin-Out
Figure 6.5 Pin-Out Diagram
Pin
Function
1
FLEXio 1—User programmable for digital/analog and input/output.
2
Flexio—Ground
3
Flexio—Ground
4
Flexio 2—User programmable for digital/analog and input/output.
Table 6.5 FLEXio Pin-Out Functions
6 Sensor
25
