Honeywell International Inc.
Cellular modem with dynamic low battery voltage threshold control

Abstract:

An industrial cellular modem includes a radio module powered by a battery, a battery voltage sensor, a transmitted power meter, and a temperature sensor, and a processor having a memory for executing program instructions for a method of dynamic low battery voltage threshold (LBVT) control. A current battery voltage is compared to a current LBVT (CLBVT), and the modem is turned on and a cellular data session begun with a host server if the current voltage is .gtoreq. the CLBVT, or if the current battery voltage is < the CLBVT and a value of the CLBVT is the same as in a previous cellular data session. Based on whether the current cellular session failed due to the battery voltage falling below the CLBVT, the value of the CLBVT is changed based on a current temperature, a received signal strength for a successful session, or a current transmit power.