Process variable measuring and display device and portable power supply
AssigneeHouston Digital Instruments, Inc.
InventorsRichard Colgate McLatchy, Jon Douglas de Silva
Life of this patent
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Abstract
This invention relates to the field of process variable measuring and display devices and portable power supplies for process variable display devices. This invention can be used to measure and display any process variable, including pressure, temperature, volume, and flow rate. Specifically, this invention relates to an electronic process variable measuring device electronically coupled to a battery powered process variable display device which displays both a bar graph trend indication of the process variable and a digital display of the process variable. In a preferred embodiment, the process variable display device is totally self-contained, including the battery operated power supply.
Claims20
A battery powered process variable display device capable of reading a process variable input signal from a process variable measuring device, comprising:
- a. a first ADC with digit drive capabilities configured to receive a process variable input signal from a process variable measuring device;
- b. a second ADC with bar graph driving capabilities configured to receive a process variable input signal from a process variable measuring device;
- c. a multi-digit LCD electronically coupled to receive an input signal from said first ADC;
- d. a multi-segment bar graph electronically coupled to receive an input signal from said second ADC;
- and
- e. a portable power supply operatively coupled to supply power to said first ADC, said second ADC, said multidigit LCD, and said multi-segment bar graph, said portable power supply comprising at least two battery assemblies arranged in parallel and further comprising a current limiting device connected in series with each of said battery assemblies, said current limiting devices capable of reducing the probability of explosion if said battery assemblies are short circuited.
A portable power supply capable of powering a process variable display device, comprising:
- a. a casing capable of protecting said portable power supply from adverse environmental conditions;
- b. two battery assemblies connected in parallel inside said casing;
- and
- c. two current limiting devices inside said casing, each of said current limiting devices connected in series with one of said battery assemblies, said current limiting devices being capable of reducing the probability of explosion if said battery assemblies are short circuited.
An intrinsically safe portable power supply comprising:
- a. a casing capable of protecting said portable power supply from adverse environmental conditions;
- b. two lithium battery assemblies connected in parallel inside said casing;
- and
- c. two current limiting devices housed in said casing, each of said current limiting devices connected in series with one of said battery assemblies, each of said current limiting devices comprising a diode and being capable of reducing the probability of explosion if said battery assemblies are short circuited.
Dependencies are inferred from the claim text.