Liquid Level Transmitter Utilizing Low Cost, Capacitive, Absolute Encoders

Abstract

A liquid level monitoring and transmission system includes a mechanical assembly in communication with the liquid in a container and a dual electronic encoder assembly in communication with the mechanical assembly for determining liquid level. The dual electronic encoder assembly includes a first encoder for encoding data indicative of fine level measurements and a second encoder for encoding data indicative of coarse level measurements. The system further includes at least one processor for controlling operation of the first and second encoders and for processing encoded data therefrom and a power control system.

1 . A process for controlling a liquid level monitoring and transmission system to determine liquid levels in multiple storage containers, the process comprising:
 interrogating, by a host server, a transmission gauge of each of the multiple storage containers periodically to obtain a composite level reading;   responsive to the interrogation by the host server, powering on a dual electronic absolute capacitive encoder assembly in communication with a mechanical assembly for determining a composite liquid level in each of the multiple storage containers;   deriving a current liquid level for each of the multiple storage containers by the host server in accordance with a filter algorithm, wherein for each of the multiple storage containers, the filter algorithm inserts successive composite level readings into an array having a predetermined number of slots, sorts the composite level readings from least to greatest value and selects a middle value in the sorted array as the current liquid level.   
     
     
         2 . The process of  claim 1 , wherein determining a composite liquid level in each of the multiple storage containers further comprises:
 powering up a first absolute capacitive encoder of the dual electronic absolute capacitive encoder assembly;   obtaining at least one fine level measurement from the first absolute capacitive encoder;   powering down the first absolute capacitive encoder;   powering up a second absolute capacitive encoder responsive to instructions;   obtaining at least one coarse level measurement from the second absolute capacitive encoder; and   powering down the second absolute capacitive encoder.   
     
     
         3 . The process of  claim 2 , wherein a time period for powering up the first absolute capacitive encoder and obtaining at least one fine level measurement is approximately  100 ms. 
     
     
         4 . The process of  claim 1 , wherein the host server interrogates the transmission gauge of each of the multiple storage containers two to three times a minute. 
     
     
         5 . The process of  claim 1 , wherein the host server interrogates the transmission gauge of each of the multiple storage containers every three to five seconds. 
     
     
         6 . The process of  claim 1 , wherein the predetermined number of slots in the array is  5 . 
     
     
         7 . A process for controlling a liquid level monitoring and transmission system to determine liquid levels in a storage container, the process comprising:
 powering on, by a processor associated with the storage container, a dual electronic absolute capacitive encoder assembly in communication with a mechanical assembly of the storage container for determining at least one composite liquid level reading for the liquid in the storage container;   transmitting, by a transmission gauge associated with the processor to a host server, the at least one composite level reading;   receiving the composite level reading by the host server,   deriving a current liquid level for the storage container by the host server in accordance with a filter algorithm, wherein the filter algorithm inserts successive composite level readings into an array having a predetermined number of slots, sorts the composite level readings from least to greatest value and selects a middle value in the sorted array as the current liquid level.   
     
     
         8 . The process of  claim 7 , wherein determining at least one composite liquid level reading in each of the storage containers further comprises:
 powering up a first absolute capacitive encoder of the dual electronic absolute capacitive encoder assembly;   obtaining at least one fine level measurement from the first absolute capacitive encoder;   powering down the first absolute capacitive encoder;   powering up a second absolute capacitive encoder responsive to instructions;   obtaining at least one coarse level measurement from the second absolute capacitive encoder; and   powering down the second absolute capacitive encoder.   
     
     
         9 . The process of  claim 8 , wherein a time period for powering up the first absolute capacitive encoder and obtaining at least one fine level measurement is approximately 100 ms. 
     
     
         10 . The process of  claim 7 , wherein the transmission gauge transmits a new at least one composite level reading for the storage container two to three times a minute. 
     
     
         11 . The process of  claim 7 , wherein the transmission gauge transmits a new at least one composite level reading for the storage container every three to five seconds. 
     
     
         12 . The process of  claim 7 , wherein the predetermined number of slots in the array is 5. 
     
     
         13 . A system for controlling a liquid level monitoring and transmission system to determine liquid levels in multiple storage containers, the system comprising:
 means for interrogating each of the multiple storage containers periodically to obtain a composite level reading;   means for determining a composite liquid level in each of the multiple storage containers;   means for deriving a current liquid level for each of the multiple storage containers including inserting successive composite level readings into an array having a predetermined number of slots, sorting the composite level readings from least to greatest value and selecting a middle value in the sorted array as the current liquid level.